* [PATCH bpf] bpf: fix unpopulated name_len field in perf_event link info [not found] <ZvqLanKfaO9dLlf4@krava> @ 2024-09-30 23:59 ` tyrone-wu 2024-10-02 11:37 ` Jiri Olsa 0 siblings, 1 reply; 20+ messages in thread From: tyrone-wu @ 2024-09-30 23:59 UTC (permalink / raw) To: olsajiri, laoar.shao, andrii.nakryiko, wudevelops, bpf Cc: ast, daniel, john.fastabend, andrii, martin.lau, eddyz87, song, yonghong.song, kpsingh, sdf, haoluo, jolsa, mykolal, shuah, kernel-patches-bot, linux-kernel, linux-kselftest Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu <wudevelops@gmail.com> --- kernel/bpf/syscall.c | 25 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--- 2 files changed, 20 insertions(+), 11 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..90b6add4d0c9 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,7 +3565,7 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { @@ -3574,18 +3574,20 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, *ulen, len); if (err) return err; } else { @@ -3609,7 +3611,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3619,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3641,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3650,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3676,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again; -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH bpf] bpf: fix unpopulated name_len field in perf_event link info 2024-09-30 23:59 ` [PATCH bpf] bpf: fix unpopulated name_len field in perf_event link info tyrone-wu @ 2024-10-02 11:37 ` Jiri Olsa 2024-10-02 21:38 ` [PATCH bpf v2] " tyrone-wu 0 siblings, 1 reply; 20+ messages in thread From: Jiri Olsa @ 2024-10-02 11:37 UTC (permalink / raw) To: tyrone-wu Cc: olsajiri, laoar.shao, andrii.nakryiko, bpf, ast, daniel, john.fastabend, andrii, martin.lau, eddyz87, song, yonghong.song, kpsingh, sdf, haoluo, mykolal, shuah, kernel-patches-bot, linux-kernel, linux-kselftest On Mon, Sep 30, 2024 at 11:59:20PM +0000, tyrone-wu wrote: > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. The > relevant selftests have also been updated to assert that `name_len` > contains the correct size rather than 0. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") > Signed-off-by: tyrone-wu <wudevelops@gmail.com> > --- > kernel/bpf/syscall.c | 25 +++++++++++++------ > .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--- > 2 files changed, 20 insertions(+), 11 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a8f1808a1ca5..90b6add4d0c9 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3565,7 +3565,7 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > } > > static int bpf_perf_link_fill_common(const struct perf_event *event, > - char __user *uname, u32 ulen, > + char __user *uname, u32 *ulen, > u64 *probe_offset, u64 *probe_addr, > u32 *fd_type, unsigned long *missed) > { > @@ -3574,18 +3574,20 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, > size_t len; > int err; > > - if (!ulen ^ !uname) > + if (!(*ulen) ^ !uname) > return -EINVAL; > > err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > probe_offset, probe_addr, missed); > if (err) > return err; > + > + len = strlen(buf); > + *ulen = len + 1; I think before you overwrite *ulen with actual name lenth you should store its value and use it in bpf_copy_to_user, otherwise we could overwrite user space memory that we are not supposed to jirka > if (!uname) > return 0; > if (buf) { > - len = strlen(buf); > - err = bpf_copy_to_user(uname, buf, ulen, len); > + err = bpf_copy_to_user(uname, buf, *ulen, len); > if (err) > return err; > } else { > @@ -3609,7 +3611,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); > ulen = info->perf_event.kprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, &missed); > if (err) > return err; SNIP ^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH bpf v2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-02 11:37 ` Jiri Olsa @ 2024-10-02 21:38 ` tyrone-wu 2024-10-03 19:10 ` Jiri Olsa 0 siblings, 1 reply; 20+ messages in thread From: tyrone-wu @ 2024-10-02 21:38 UTC (permalink / raw) To: olsajiri, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu <wudevelops@gmail.com> --- V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen kernel/bpf/syscall.c | 29 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- 2 files changed, 23 insertions(+), 12 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..26cc18693924 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; u32 prog_id; - size_t len; + size_t len, name_len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + name_len = *ulen; + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, name_len, len); if (err) return err; } else { @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again; -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-02 21:38 ` [PATCH bpf v2] " tyrone-wu @ 2024-10-03 19:10 ` Jiri Olsa 2024-10-03 20:23 ` [PATCH bpf v3] " tyrone-wu 0 siblings, 1 reply; 20+ messages in thread From: Jiri Olsa @ 2024-10-03 19:10 UTC (permalink / raw) To: tyrone-wu Cc: olsajiri, andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song On Wed, Oct 02, 2024 at 09:38:39PM +0000, tyrone-wu wrote: > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. The > relevant selftests have also been updated to assert that `name_len` > contains the correct size rather than 0. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") > Signed-off-by: tyrone-wu <wudevelops@gmail.com> > --- > V1 -> V2: > Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ > - Use user set *ulen in bpf_copy_to_user before overwriting *ulen > > kernel/bpf/syscall.c | 29 +++++++++++++------ > .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- > 2 files changed, 23 insertions(+), 12 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a8f1808a1ca5..26cc18693924 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > } > > static int bpf_perf_link_fill_common(const struct perf_event *event, > - char __user *uname, u32 ulen, > + char __user *uname, u32 *ulen, > u64 *probe_offset, u64 *probe_addr, > u32 *fd_type, unsigned long *missed) > { > const char *buf; > u32 prog_id; > - size_t len; > + size_t len, name_len; > int err; > > - if (!ulen ^ !uname) > + if (!(*ulen) ^ !uname) > return -EINVAL; > > err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > probe_offset, probe_addr, missed); > if (err) > return err; > + > + name_len = *ulen; > + len = strlen(buf); > + *ulen = len + 1; > if (!uname) > return 0; > + > if (buf) { > - len = strlen(buf); > - err = bpf_copy_to_user(uname, buf, ulen, len); > + err = bpf_copy_to_user(uname, buf, name_len, len); > if (err) > return err; > } else { small nit.. up to you but I'd suggest bit different naming like below, otherwise looks good Acked-by: Jiri Olsa <jolsa@kernel.org> thanks, jirka --- diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..b637e9dced5a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,26 +3565,28 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulenp, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, ulen; size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulenp) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + ulen = *ulenp; + len = strlen(buf); + *ulenp = len + 1; if (!uname) return 0; if (buf) { - len = strlen(buf); err = bpf_copy_to_user(uname, buf, ulen, len); if (err) return err; ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH bpf v3] bpf: fix unpopulated name_len field in perf_event link info 2024-10-03 19:10 ` Jiri Olsa @ 2024-10-03 20:23 ` tyrone-wu 2024-10-04 11:19 ` Jiri Olsa 0 siblings, 1 reply; 20+ messages in thread From: tyrone-wu @ 2024-10-03 20:23 UTC (permalink / raw) To: olsajiri, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu <wudevelops@gmail.com> --- V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen kernel/bpf/syscall.c | 29 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- 2 files changed, 23 insertions(+), 12 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..56c556fcf325 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else { @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again; -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v3] bpf: fix unpopulated name_len field in perf_event link info 2024-10-03 20:23 ` [PATCH bpf v3] " tyrone-wu @ 2024-10-04 11:19 ` Jiri Olsa 2024-10-04 15:40 ` [PATCH bpf v4 1/2] " tyrone-wu 0 siblings, 1 reply; 20+ messages in thread From: Jiri Olsa @ 2024-10-04 11:19 UTC (permalink / raw) To: tyrone-wu Cc: olsajiri, andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song On Thu, Oct 03, 2024 at 08:23:00PM +0000, tyrone-wu wrote: > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. The > relevant selftests have also been updated to assert that `name_len` > contains the correct size rather than 0. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") > Signed-off-by: tyrone-wu <wudevelops@gmail.com> > --- > V2 -> V3: > Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ > - Use clearer variable name for user set/inputted name len (name_len -> input_len) > - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 looks good, I checked with Daniel and it's better to separate kernel and selftest changes, so it's easier to get this applied in stable branches could you split the change in 2 changes and repost? please keep my ack thanks, jirka > > V1 -> V2: > Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ > - Use user set *ulen in bpf_copy_to_user before overwriting *ulen > > kernel/bpf/syscall.c | 29 +++++++++++++------ > .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- > 2 files changed, 23 insertions(+), 12 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a8f1808a1ca5..56c556fcf325 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > } > > static int bpf_perf_link_fill_common(const struct perf_event *event, > - char __user *uname, u32 ulen, > + char __user *uname, u32 *ulen, > u64 *probe_offset, u64 *probe_addr, > u32 *fd_type, unsigned long *missed) > { > const char *buf; > - u32 prog_id; > + u32 prog_id, input_len; > size_t len; > int err; > > - if (!ulen ^ !uname) > + if (!(*ulen) ^ !uname) > return -EINVAL; > > err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > probe_offset, probe_addr, missed); > if (err) > return err; > + > + input_len = *ulen; > + len = strlen(buf); > + *ulen = len + 1; > if (!uname) > return 0; > + > if (buf) { > - len = strlen(buf); > - err = bpf_copy_to_user(uname, buf, ulen, len); > + err = bpf_copy_to_user(uname, buf, input_len, len); > if (err) > return err; > } else { > @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); > ulen = info->perf_event.kprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, &missed); > if (err) > return err; > @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_KPROBE; > - > + info->perf_event.kprobe.name_len = ulen; > info->perf_event.kprobe.offset = offset; > info->perf_event.kprobe.missed = missed; > if (!kallsyms_show_value(current_cred())) > @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); > ulen = info->perf_event.uprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, NULL); > if (err) > return err; > @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_URETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_UPROBE; > + info->perf_event.uprobe.name_len = ulen; > info->perf_event.uprobe.offset = offset; > info->perf_event.uprobe.cookie = event->bpf_cookie; > return 0; > @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, > { > char __user *uname; > u32 ulen; > + int err; > > uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); > ulen = info->perf_event.tracepoint.name_len; > + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); > + if (err) > + return err; > + > info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; > + info->perf_event.tracepoint.name_len = ulen; > info->perf_event.tracepoint.cookie = event->bpf_cookie; > - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); > + return 0; > } > > static int bpf_perf_link_fill_perf_event(const struct perf_event *event, > diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > index f3932941bbaa..59077f260404 100644 > --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add > > ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); > > + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); > if (!info.perf_event.kprobe.func_name) { > - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); > info.perf_event.kprobe.func_name = ptr_to_u64(&buf); > info.perf_event.kprobe.name_len = sizeof(buf); > goto again; > @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add > ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); > break; > case BPF_PERF_EVENT_TRACEPOINT: > + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); > if (!info.perf_event.tracepoint.tp_name) { > - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); > info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); > info.perf_event.tracepoint.name_len = sizeof(buf); > goto again; > @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add > case BPF_PERF_EVENT_URETPROBE: > ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); > > + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); > if (!info.perf_event.uprobe.file_name) { > - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); > info.perf_event.uprobe.file_name = ptr_to_u64(&buf); > info.perf_event.uprobe.name_len = sizeof(buf); > goto again; > -- > 2.43.0 > ^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH bpf v4 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-04 11:19 ` Jiri Olsa @ 2024-10-04 15:40 ` tyrone-wu 2024-10-04 15:40 ` [PATCH bpf v4 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu 2024-10-06 6:00 ` [PATCH bpf v4 1/2] bpf: fix unpopulated name_len field in perf_event link info Yafang Shao 0 siblings, 2 replies; 20+ messages in thread From: tyrone-wu @ 2024-10-04 15:40 UTC (permalink / raw) To: olsajiri, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song, Jiri Olsa Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> --- V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen kernel/bpf/syscall.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..56c556fcf325 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else { @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH bpf v4 2/2] selftests/bpf: fix perf_event link info name_len assertion 2024-10-04 15:40 ` [PATCH bpf v4 1/2] " tyrone-wu @ 2024-10-04 15:40 ` tyrone-wu 2024-10-06 6:00 ` [PATCH bpf v4 1/2] bpf: fix unpopulated name_len field in perf_event link info Yafang Shao 1 sibling, 0 replies; 20+ messages in thread From: tyrone-wu @ 2024-10-04 15:40 UTC (permalink / raw) To: olsajiri, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song, Jiri Olsa Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: tyrone-wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> --- V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again; -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v4 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-04 15:40 ` [PATCH bpf v4 1/2] " tyrone-wu 2024-10-04 15:40 ` [PATCH bpf v4 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu @ 2024-10-06 6:00 ` Yafang Shao 2024-10-06 19:51 ` [PATCH bpf v5 " tyrone-wu 1 sibling, 1 reply; 20+ messages in thread From: Yafang Shao @ 2024-10-06 6:00 UTC (permalink / raw) To: tyrone-wu Cc: olsajiri, andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song, Jiri Olsa On Fri, Oct 4, 2024 at 11:40 PM tyrone-wu <wudevelops@gmail.com> wrote: > > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") > Signed-off-by: tyrone-wu <wudevelops@gmail.com> > Acked-by: Jiri Olsa <jolsa@kernel.org> > --- > V3 -> V4: > Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ > - Split patch into separate kernel and selftest change > > V2 -> V3: > Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ > - Use clearer variable name for user set/inputted name len (name_len -> input_len) > - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 > > V1 -> V2: > Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ > - Use user set *ulen in bpf_copy_to_user before overwriting *ulen > > kernel/bpf/syscall.c | 29 ++++++++++++++++++++--------- > 1 file changed, 20 insertions(+), 9 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a8f1808a1ca5..56c556fcf325 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > } > > static int bpf_perf_link_fill_common(const struct perf_event *event, > - char __user *uname, u32 ulen, > + char __user *uname, u32 *ulen, > u64 *probe_offset, u64 *probe_addr, > u32 *fd_type, unsigned long *missed) > { > const char *buf; > - u32 prog_id; > + u32 prog_id, input_len; > size_t len; > int err; > > - if (!ulen ^ !uname) > + if (!(*ulen) ^ !uname) > return -EINVAL; > > err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > probe_offset, probe_addr, missed); > if (err) > return err; > + > + input_len = *ulen; > + len = strlen(buf); The buf might be NULL, so we should check it. > + *ulen = len + 1; > if (!uname) > return 0; > + > if (buf) { > - len = strlen(buf); > - err = bpf_copy_to_user(uname, buf, ulen, len); > + err = bpf_copy_to_user(uname, buf, input_len, len); > if (err) > return err; > } else { > @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); > ulen = info->perf_event.kprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, &missed); > if (err) > return err; > @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_KPROBE; > - > + info->perf_event.kprobe.name_len = ulen; > info->perf_event.kprobe.offset = offset; > info->perf_event.kprobe.missed = missed; > if (!kallsyms_show_value(current_cred())) > @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); > ulen = info->perf_event.uprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, NULL); > if (err) > return err; > @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_URETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_UPROBE; > + info->perf_event.uprobe.name_len = ulen; > info->perf_event.uprobe.offset = offset; > info->perf_event.uprobe.cookie = event->bpf_cookie; > return 0; > @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, > { > char __user *uname; > u32 ulen; > + int err; > > uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); > ulen = info->perf_event.tracepoint.name_len; > + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); > + if (err) > + return err; > + > info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; > + info->perf_event.tracepoint.name_len = ulen; > info->perf_event.tracepoint.cookie = event->bpf_cookie; > - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); > + return 0; > } > > static int bpf_perf_link_fill_perf_event(const struct perf_event *event, > -- > 2.43.0 > -- Regards Yafang ^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH bpf v5 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-06 6:00 ` [PATCH bpf v4 1/2] bpf: fix unpopulated name_len field in perf_event link info Yafang Shao @ 2024-10-06 19:51 ` tyrone-wu 2024-10-06 19:51 ` [PATCH bpf v5 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu ` (2 more replies) 0 siblings, 3 replies; 20+ messages in thread From: tyrone-wu @ 2024-10-06 19:51 UTC (permalink / raw) To: laoar.shao, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, jolsa, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> --- V4 -> V5: Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/ - Check that buf is not NULL before retrieving/using its length V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..3df192a6bdcc 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; - if (!uname) - return 0; + if (buf) { + input_len = *ulen; len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); - if (err) - return err; - } else { - char zero = '\0'; + *ulen = len + 1; + if (uname) { + err = bpf_copy_to_user(uname, buf, input_len, len); + if (err) + return err; + } + } else if (uname) { + char zero = '\0'; if (put_user(zero, uname)) return -EFAULT; } @@ -3609,7 +3612,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3620,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3642,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3651,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3677,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH bpf v5 2/2] selftests/bpf: fix perf_event link info name_len assertion 2024-10-06 19:51 ` [PATCH bpf v5 " tyrone-wu @ 2024-10-06 19:51 ` tyrone-wu 2024-10-07 2:09 ` Yafang Shao 2024-10-07 2:09 ` [PATCH bpf v5 1/2] bpf: fix unpopulated name_len field in perf_event link info Yafang Shao 2024-10-07 8:07 ` Jiri Olsa 2 siblings, 1 reply; 20+ messages in thread From: tyrone-wu @ 2024-10-06 19:51 UTC (permalink / raw) To: laoar.shao, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, jolsa, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: tyrone-wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> --- V4 -> V5: no change V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again; -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v5 2/2] selftests/bpf: fix perf_event link info name_len assertion 2024-10-06 19:51 ` [PATCH bpf v5 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu @ 2024-10-07 2:09 ` Yafang Shao 0 siblings, 0 replies; 20+ messages in thread From: Yafang Shao @ 2024-10-07 2:09 UTC (permalink / raw) To: tyrone-wu Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, jolsa, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song On Mon, Oct 7, 2024 at 3:51 AM tyrone-wu <wudevelops@gmail.com> wrote: > > Fix `name_len` field assertions in `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint to validate correct name size instead of 0. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") > Signed-off-by: tyrone-wu <wudevelops@gmail.com> > Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Yafang Shao <laoar.shao@gmail.com> > --- > V4 -> V5: no change > > V3 -> V4: > Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ > - Split patch into separate kernel and selftest change > > tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > index f3932941bbaa..59077f260404 100644 > --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c > @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add > > ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); > > + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); > if (!info.perf_event.kprobe.func_name) { > - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); > info.perf_event.kprobe.func_name = ptr_to_u64(&buf); > info.perf_event.kprobe.name_len = sizeof(buf); > goto again; > @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add > ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); > break; > case BPF_PERF_EVENT_TRACEPOINT: > + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); > if (!info.perf_event.tracepoint.tp_name) { > - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); > info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); > info.perf_event.tracepoint.name_len = sizeof(buf); > goto again; > @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add > case BPF_PERF_EVENT_URETPROBE: > ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); > > + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); > if (!info.perf_event.uprobe.file_name) { > - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); > info.perf_event.uprobe.file_name = ptr_to_u64(&buf); > info.perf_event.uprobe.name_len = sizeof(buf); > goto again; > -- > 2.43.0 > -- Regards Yafang ^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v5 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-06 19:51 ` [PATCH bpf v5 " tyrone-wu 2024-10-06 19:51 ` [PATCH bpf v5 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu @ 2024-10-07 2:09 ` Yafang Shao 2024-10-07 8:07 ` Jiri Olsa 2 siblings, 0 replies; 20+ messages in thread From: Yafang Shao @ 2024-10-07 2:09 UTC (permalink / raw) To: tyrone-wu Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, jolsa, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song On Mon, Oct 7, 2024 at 3:51 AM tyrone-wu <wudevelops@gmail.com> wrote: > > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") > Signed-off-by: tyrone-wu <wudevelops@gmail.com> > Acked-by: Jiri Olsa <jolsa@kernel.org> LGTM Acked-by: Yafang Shao <laoar.shao@gmail.com> > --- > V4 -> V5: > Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/ > - Check that buf is not NULL before retrieving/using its length > > V3 -> V4: > Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ > - Split patch into separate kernel and selftest change > > V2 -> V3: > Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ > - Use clearer variable name for user set/inputted name len (name_len -> input_len) > - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 > > V1 -> V2: > Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ > - Use user set *ulen in bpf_copy_to_user before overwriting *ulen > > kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++-------------- > 1 file changed, 24 insertions(+), 14 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a8f1808a1ca5..3df192a6bdcc 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > } > > static int bpf_perf_link_fill_common(const struct perf_event *event, > - char __user *uname, u32 ulen, > + char __user *uname, u32 *ulen, > u64 *probe_offset, u64 *probe_addr, > u32 *fd_type, unsigned long *missed) > { > const char *buf; > - u32 prog_id; > + u32 prog_id, input_len; > size_t len; > int err; > > - if (!ulen ^ !uname) > + if (!(*ulen) ^ !uname) > return -EINVAL; > > err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > probe_offset, probe_addr, missed); > if (err) > return err; > - if (!uname) > - return 0; > + > if (buf) { > + input_len = *ulen; > len = strlen(buf); > - err = bpf_copy_to_user(uname, buf, ulen, len); > - if (err) > - return err; > - } else { > - char zero = '\0'; > + *ulen = len + 1; > > + if (uname) { > + err = bpf_copy_to_user(uname, buf, input_len, len); > + if (err) > + return err; > + } > + } else if (uname) { > + char zero = '\0'; > if (put_user(zero, uname)) > return -EFAULT; > } > @@ -3609,7 +3612,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); > ulen = info->perf_event.kprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, &missed); > if (err) > return err; > @@ -3617,7 +3620,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_KPROBE; > - > + info->perf_event.kprobe.name_len = ulen; > info->perf_event.kprobe.offset = offset; > info->perf_event.kprobe.missed = missed; > if (!kallsyms_show_value(current_cred())) > @@ -3639,7 +3642,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); > ulen = info->perf_event.uprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, NULL); > if (err) > return err; > @@ -3648,6 +3651,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_URETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_UPROBE; > + info->perf_event.uprobe.name_len = ulen; > info->perf_event.uprobe.offset = offset; > info->perf_event.uprobe.cookie = event->bpf_cookie; > return 0; > @@ -3673,12 +3677,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, > { > char __user *uname; > u32 ulen; > + int err; > > uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); > ulen = info->perf_event.tracepoint.name_len; > + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); > + if (err) > + return err; > + > info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; > + info->perf_event.tracepoint.name_len = ulen; > info->perf_event.tracepoint.cookie = event->bpf_cookie; > - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); > + return 0; > } > > static int bpf_perf_link_fill_perf_event(const struct perf_event *event, > -- > 2.43.0 > -- Regards Yafang ^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v5 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-06 19:51 ` [PATCH bpf v5 " tyrone-wu 2024-10-06 19:51 ` [PATCH bpf v5 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu 2024-10-07 2:09 ` [PATCH bpf v5 1/2] bpf: fix unpopulated name_len field in perf_event link info Yafang Shao @ 2024-10-07 8:07 ` Jiri Olsa 2024-10-07 18:29 ` [PATCH bpf v6 " Tyrone Wu 2 siblings, 1 reply; 20+ messages in thread From: Jiri Olsa @ 2024-10-07 8:07 UTC (permalink / raw) To: tyrone-wu Cc: laoar.shao, andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song On Sun, Oct 06, 2024 at 07:51:30PM +0000, tyrone-wu wrote: > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") > Signed-off-by: tyrone-wu <wudevelops@gmail.com> > Acked-by: Jiri Olsa <jolsa@kernel.org> > --- > V4 -> V5: > Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/ > - Check that buf is not NULL before retrieving/using its length > > V3 -> V4: > Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ > - Split patch into separate kernel and selftest change > > V2 -> V3: > Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ > - Use clearer variable name for user set/inputted name len (name_len -> input_len) > - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 > > V1 -> V2: > Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ > - Use user set *ulen in bpf_copy_to_user before overwriting *ulen > > kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++-------------- > 1 file changed, 24 insertions(+), 14 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a8f1808a1ca5..3df192a6bdcc 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > } > > static int bpf_perf_link_fill_common(const struct perf_event *event, > - char __user *uname, u32 ulen, > + char __user *uname, u32 *ulen, > u64 *probe_offset, u64 *probe_addr, > u32 *fd_type, unsigned long *missed) > { > const char *buf; > - u32 prog_id; > + u32 prog_id, input_len; > size_t len; > int err; > > - if (!ulen ^ !uname) > + if (!(*ulen) ^ !uname) > return -EINVAL; > > err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > probe_offset, probe_addr, missed); > if (err) > return err; > - if (!uname) > - return 0; > + > if (buf) { > + input_len = *ulen; > len = strlen(buf); > - err = bpf_copy_to_user(uname, buf, ulen, len); > - if (err) > - return err; > - } else { > - char zero = '\0'; > + *ulen = len + 1; > > + if (uname) { > + err = bpf_copy_to_user(uname, buf, input_len, len); > + if (err) > + return err; > + } > + } else if (uname) { > + char zero = '\0'; > if (put_user(zero, uname)) > return -EFAULT; > } hm, why not just simple check buf for and keep the rest? seems less complicated.. jirka --- diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..e393b94b90ec 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + if (buf) { + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; + } if (!uname) return 0; if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else { ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH bpf v6 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-07 8:07 ` Jiri Olsa @ 2024-10-07 18:29 ` Tyrone Wu 2024-10-07 18:29 ` [PATCH bpf v6 2/2] selftests/bpf: fix perf_event link info name_len assertion Tyrone Wu 2024-10-08 4:04 ` [PATCH bpf v6 1/2] bpf: fix unpopulated name_len field in perf_event link info Andrii Nakryiko 0 siblings, 2 replies; 20+ messages in thread From: Tyrone Wu @ 2024-10-07 18:29 UTC (permalink / raw) To: olsajiri, laoar.shao, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song, Jiri Olsa From: tyrone-wu <wudevelops@gmail.com> Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: Tyrone Wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Yafang Shao <laoar.shao@gmail.com> --- V5 -> V6: Link: https://lore.kernel.org/bpf/ZwOWs_XrBtlTGE24@krava/ - Use simpler buf check while keeping V4 - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username V4 -> V5: Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/ - Check that buf is not NULL before retrieving/using its length V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen kernel/bpf/syscall.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..b5a7e428ac16 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,33 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err; - if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + if (buf) { + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; + } if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else { @@ -3609,7 +3615,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3623,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3645,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3654,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3680,19 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, + NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH bpf v6 2/2] selftests/bpf: fix perf_event link info name_len assertion 2024-10-07 18:29 ` [PATCH bpf v6 " Tyrone Wu @ 2024-10-07 18:29 ` Tyrone Wu 2024-10-08 4:04 ` [PATCH bpf v6 1/2] bpf: fix unpopulated name_len field in perf_event link info Andrii Nakryiko 1 sibling, 0 replies; 20+ messages in thread From: Tyrone Wu @ 2024-10-07 18:29 UTC (permalink / raw) To: olsajiri, laoar.shao, wudevelops Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song, Jiri Olsa From: tyrone-wu <wudevelops@gmail.com> Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0. Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: Tyrone Wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Yafang Shao <laoar.shao@gmail.com> --- V5 -> V6: - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username V4 -> V5: no change V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..745c5ada4c4b 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, + "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +80,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, + "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +98,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, + "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again; -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v6 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-07 18:29 ` [PATCH bpf v6 " Tyrone Wu 2024-10-07 18:29 ` [PATCH bpf v6 2/2] selftests/bpf: fix perf_event link info name_len assertion Tyrone Wu @ 2024-10-08 4:04 ` Andrii Nakryiko 2024-10-08 16:43 ` [PATCH bpf v7 " Tyrone Wu 1 sibling, 1 reply; 20+ messages in thread From: Andrii Nakryiko @ 2024-10-08 4:04 UTC (permalink / raw) To: Tyrone Wu Cc: olsajiri, laoar.shao, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, kernel-patches-bot, kpsingh, linux-kernel, linux-kselftest, martin.lau, mykolal, sdf, shuah, song, yonghong.song, Jiri Olsa On Mon, Oct 7, 2024 at 11:29 AM Tyrone Wu <wudevelops@gmail.com> wrote: > > From: tyrone-wu <wudevelops@gmail.com> > > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. > > Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snztmtg@mail.gmail.com/ > Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") > Signed-off-by: Tyrone Wu <wudevelops@gmail.com> > Acked-by: Jiri Olsa <jolsa@kernel.org> > Acked-by: Yafang Shao <laoar.shao@gmail.com> > --- > V5 -> V6: > Link: https://lore.kernel.org/bpf/ZwOWs_XrBtlTGE24@krava/ > - Use simpler buf check while keeping V4 > - Fix netdev/checkpatch warning for 80 cols exceeded > - Fix Signed-off-by to use real name instead of git username > > V4 -> V5: > Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZp-Q@mail.gmail.com/ > - Check that buf is not NULL before retrieving/using its length > > V3 -> V4: > Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ > - Split patch into separate kernel and selftest change > > V2 -> V3: > Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ > - Use clearer variable name for user set/inputted name len (name_len -> input_len) > - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 > > V1 -> V2: > Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ Please drop all the Link: tags, our scripts will accumulate all of them in the final commit and it becomes very confusing. Our script will add the final Link: for your latest applied version anyways. Also, git still shows: Author: tyrone-wu <wudevelops@gmail.com> So please try to fix that. But generally, looks good and I almost applied, but see one small issue below, which I think needs fixing. pw-bot: cr > - Use user set *ulen in bpf_copy_to_user before overwriting *ulen > > kernel/bpf/syscall.c | 32 +++++++++++++++++++++++--------- > 1 file changed, 23 insertions(+), 9 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index a8f1808a1ca5..b5a7e428ac16 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -3565,27 +3565,33 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) > } > > static int bpf_perf_link_fill_common(const struct perf_event *event, > - char __user *uname, u32 ulen, > + char __user *uname, u32 *ulen, nit: I'd do what Jiri suggested, use `u32 *ulenp` here > u64 *probe_offset, u64 *probe_addr, > u32 *fd_type, unsigned long *missed) > { > const char *buf; > - u32 prog_id; > + u32 prog_id, input_len; and then just `u32 ulen;` here. > size_t len; > int err; > start with just ulen = *ulenp; > - if (!ulen ^ !uname) > + if (!(*ulen) ^ !uname) and remove all the `*ulen` uses except the final assignment > return -EINVAL; > > err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, > probe_offset, probe_addr, missed); > if (err) > return err; > + > + if (buf) { > + input_len = *ulen; > + len = strlen(buf); > + *ulen = len + 1; > + } don't we need } else { *ulen = 1; } for cases when we don't have buf returned from bpf_get_perf_event_info()? Though I don't think it can happen currently, existing code is clearly ready to handle that case, so let's keep it consistent. > if (!uname) > return 0; > + > if (buf) { > - len = strlen(buf); > - err = bpf_copy_to_user(uname, buf, ulen, len); > + err = bpf_copy_to_user(uname, buf, input_len, len); > if (err) > return err; > } else { > @@ -3609,7 +3615,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); > ulen = info->perf_event.kprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, &missed); > if (err) > return err; > @@ -3617,7 +3623,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_KPROBE; > - > + info->perf_event.kprobe.name_len = ulen; > info->perf_event.kprobe.offset = offset; > info->perf_event.kprobe.missed = missed; > if (!kallsyms_show_value(current_cred())) > @@ -3639,7 +3645,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > > uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); > ulen = info->perf_event.uprobe.name_len; > - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, > + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, > &type, NULL); > if (err) > return err; > @@ -3648,6 +3654,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, > info->perf_event.type = BPF_PERF_EVENT_URETPROBE; > else > info->perf_event.type = BPF_PERF_EVENT_UPROBE; > + info->perf_event.uprobe.name_len = ulen; > info->perf_event.uprobe.offset = offset; > info->perf_event.uprobe.cookie = event->bpf_cookie; > return 0; > @@ -3673,12 +3680,19 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, > { > char __user *uname; > u32 ulen; > + int err; > > uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); > ulen = info->perf_event.tracepoint.name_len; > + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, > + NULL); nit: keep it on a single line > + if (err) > + return err; > + > info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; > + info->perf_event.tracepoint.name_len = ulen; > info->perf_event.tracepoint.cookie = event->bpf_cookie; > - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); > + return 0; > } > > static int bpf_perf_link_fill_perf_event(const struct perf_event *event, > -- > 2.43.0 > ^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH bpf v7 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-08 4:04 ` [PATCH bpf v6 1/2] bpf: fix unpopulated name_len field in perf_event link info Andrii Nakryiko @ 2024-10-08 16:43 ` Tyrone Wu 2024-10-08 16:43 ` [PATCH bpf v7 2/2] selftests/bpf: fix perf_event link info name_len assertion Tyrone Wu 2024-10-10 1:20 ` [PATCH bpf v7 1/2] bpf: fix unpopulated name_len field in perf_event link info patchwork-bot+netdevbpf 0 siblings, 2 replies; 20+ messages in thread From: Tyrone Wu @ 2024-10-08 16:43 UTC (permalink / raw) To: andrii.nakryiko, wudevelops Cc: andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, jolsa, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`). This patch fills `name_len` with the actual size of the string name. Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: Tyrone Wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Yafang Shao <laoar.shao@gmail.com> --- V6 -> V7: - Use *ulenp suggestion from Jiri for user name_len - Set user name_len to 1 when buf returned from bpf_get_perf_event_info() is NULL V5 -> V6: - Use simpler buf check while keeping V4 - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username V4 -> V5: - Check that buf is not NULL before retrieving/using its length V3 -> V4: - Split patch into separate kernel and selftest change V2 -> V3: - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32 V1 -> V2: - Use user set *ulen in bpf_copy_to_user before overwriting *ulen kernel/bpf/syscall.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..8cfa7183d2ef 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,15 +3565,16 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulenp, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, ulen; size_t len; int err; + ulen = *ulenp; if (!ulen ^ !uname) return -EINVAL; @@ -3581,10 +3582,17 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, probe_offset, probe_addr, missed); if (err) return err; + + if (buf) { + len = strlen(buf); + *ulenp = len + 1; + } else { + *ulenp = 1; + } if (!uname) return 0; + if (buf) { - len = strlen(buf); err = bpf_copy_to_user(uname, buf, ulen, len); if (err) return err; @@ -3609,7 +3617,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3625,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3647,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3656,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3682,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; } static int bpf_perf_link_fill_perf_event(const struct perf_event *event, -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH bpf v7 2/2] selftests/bpf: fix perf_event link info name_len assertion 2024-10-08 16:43 ` [PATCH bpf v7 " Tyrone Wu @ 2024-10-08 16:43 ` Tyrone Wu 2024-10-10 1:20 ` [PATCH bpf v7 1/2] bpf: fix unpopulated name_len field in perf_event link info patchwork-bot+netdevbpf 1 sibling, 0 replies; 20+ messages in thread From: Tyrone Wu @ 2024-10-08 16:43 UTC (permalink / raw) To: andrii.nakryiko, wudevelops Cc: andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, jolsa, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0. Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: Tyrone Wu <wudevelops@gmail.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Yafang Shao <laoar.shao@gmail.com> --- V6 -> V7: no change V5 -> V6: - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username V4 -> V5: no change V3 -> V4: - Split patch into separate kernel and selftest change tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..745c5ada4c4b 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie"); + ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, + "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +80,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, + "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +98,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset"); + ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, + "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again; -- 2.43.0 ^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH bpf v7 1/2] bpf: fix unpopulated name_len field in perf_event link info 2024-10-08 16:43 ` [PATCH bpf v7 " Tyrone Wu 2024-10-08 16:43 ` [PATCH bpf v7 2/2] selftests/bpf: fix perf_event link info name_len assertion Tyrone Wu @ 2024-10-10 1:20 ` patchwork-bot+netdevbpf 1 sibling, 0 replies; 20+ messages in thread From: patchwork-bot+netdevbpf @ 2024-10-10 1:20 UTC (permalink / raw) To: Tyrone Wu Cc: andrii.nakryiko, andrii, ast, bpf, daniel, eddyz87, haoluo, john.fastabend, jolsa, kernel-patches-bot, kpsingh, laoar.shao, linux-kernel, linux-kselftest, martin.lau, mykolal, olsajiri, sdf, shuah, song, yonghong.song Hello: This series was applied to bpf/bpf.git (master) by Alexei Starovoitov <ast@kernel.org>: On Tue, 8 Oct 2024 16:43:11 +0000 you wrote: > Previously when retrieving `bpf_link_info.perf_event` for > kprobe/uprobe/tracepoint, the `name_len` field was not populated by the > kernel, leaving it to reflect the value initially set by the user. This > behavior was inconsistent with how other input/output string buffer > fields function (e.g. `raw_tracepoint.tp_name_len`). > > This patch fills `name_len` with the actual size of the string name. > > [...] Here is the summary with links: - [bpf,v7,1/2] bpf: fix unpopulated name_len field in perf_event link info https://git.kernel.org/bpf/bpf/c/4deecdd29cf2 - [bpf,v7,2/2] selftests/bpf: fix perf_event link info name_len assertion https://git.kernel.org/bpf/bpf/c/4538a38f654a You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html ^ permalink raw reply [flat|nested] 20+ messages in thread
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Thread overview: 20+ messages (download: mbox.gz follow: Atom feed
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2024-09-30 23:59 ` [PATCH bpf] bpf: fix unpopulated name_len field in perf_event link info tyrone-wu
2024-10-02 11:37 ` Jiri Olsa
2024-10-02 21:38 ` [PATCH bpf v2] " tyrone-wu
2024-10-03 19:10 ` Jiri Olsa
2024-10-03 20:23 ` [PATCH bpf v3] " tyrone-wu
2024-10-04 11:19 ` Jiri Olsa
2024-10-04 15:40 ` [PATCH bpf v4 1/2] " tyrone-wu
2024-10-04 15:40 ` [PATCH bpf v4 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu
2024-10-06 6:00 ` [PATCH bpf v4 1/2] bpf: fix unpopulated name_len field in perf_event link info Yafang Shao
2024-10-06 19:51 ` [PATCH bpf v5 " tyrone-wu
2024-10-06 19:51 ` [PATCH bpf v5 2/2] selftests/bpf: fix perf_event link info name_len assertion tyrone-wu
2024-10-07 2:09 ` Yafang Shao
2024-10-07 2:09 ` [PATCH bpf v5 1/2] bpf: fix unpopulated name_len field in perf_event link info Yafang Shao
2024-10-07 8:07 ` Jiri Olsa
2024-10-07 18:29 ` [PATCH bpf v6 " Tyrone Wu
2024-10-07 18:29 ` [PATCH bpf v6 2/2] selftests/bpf: fix perf_event link info name_len assertion Tyrone Wu
2024-10-08 4:04 ` [PATCH bpf v6 1/2] bpf: fix unpopulated name_len field in perf_event link info Andrii Nakryiko
2024-10-08 16:43 ` [PATCH bpf v7 " Tyrone Wu
2024-10-08 16:43 ` [PATCH bpf v7 2/2] selftests/bpf: fix perf_event link info name_len assertion Tyrone Wu
2024-10-10 1:20 ` [PATCH bpf v7 1/2] bpf: fix unpopulated name_len field in perf_event link info patchwork-bot+netdevbpf
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