* [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC
@ 2023-05-25 22:13 Andrii Nakryiko
2023-05-25 22:13 ` [PATCH bpf-next 2/2] libbpf: ensure FD >= 3 during bpf_map__reuse_fd() Andrii Nakryiko
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: Andrii Nakryiko @ 2023-05-25 22:13 UTC (permalink / raw)
To: bpf, ast, daniel, martin.lau; +Cc: lennart, Andrii Nakryiko
Make sure that libbpf code always gets FD with O_CLOEXEC flag set,
regardless if file is open through open() or fopen(). For the latter
this means to add "e" to mode string, which is supported since pretty
ancient glibc v2.7.
I also dropped outdated TODO comment in usdt.c, which was already completed.
Suggested-by: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/btf.c | 2 +-
tools/lib/bpf/libbpf.c | 6 +++---
tools/lib/bpf/libbpf_probes.c | 2 +-
tools/lib/bpf/usdt.c | 5 ++---
4 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
index 0a2c079244b6..8484b563b53d 100644
--- a/tools/lib/bpf/btf.c
+++ b/tools/lib/bpf/btf.c
@@ -1064,7 +1064,7 @@ static struct btf *btf_parse_raw(const char *path, struct btf *base_btf)
int err = 0;
long sz;
- f = fopen(path, "rb");
+ f = fopen(path, "rbe");
if (!f) {
err = -errno;
goto err_out;
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 1ceb3a97dadc..60ef4c5e3bee 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4351,7 +4351,7 @@ static int bpf_get_map_info_from_fdinfo(int fd, struct bpf_map_info *info)
snprintf(file, sizeof(file), "/proc/%d/fdinfo/%d", getpid(), fd);
memset(info, 0, sizeof(*info));
- fp = fopen(file, "r");
+ fp = fopen(file, "re");
if (!fp) {
err = -errno;
pr_warn("failed to open %s: %d. No procfs support?\n", file,
@@ -7455,7 +7455,7 @@ int libbpf_kallsyms_parse(kallsyms_cb_t cb, void *ctx)
int ret, err = 0;
FILE *f;
- f = fopen("/proc/kallsyms", "r");
+ f = fopen("/proc/kallsyms", "re");
if (!f) {
err = -errno;
pr_warn("failed to open /proc/kallsyms: %d\n", err);
@@ -10075,7 +10075,7 @@ static int parse_uint_from_file(const char *file, const char *fmt)
int err, ret;
FILE *f;
- f = fopen(file, "r");
+ f = fopen(file, "re");
if (!f) {
err = -errno;
pr_debug("failed to open '%s': %s\n", file,
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 6065f408a59c..5f78a023b474 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -38,7 +38,7 @@ static __u32 get_ubuntu_kernel_version(void)
if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) != 0)
return 0;
- f = fopen(ubuntu_kver_file, "r");
+ f = fopen(ubuntu_kver_file, "re");
if (!f)
return 0;
diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c
index 086eef355ab3..f1a141555f08 100644
--- a/tools/lib/bpf/usdt.c
+++ b/tools/lib/bpf/usdt.c
@@ -466,7 +466,7 @@ static int parse_vma_segs(int pid, const char *lib_path, struct elf_seg **segs,
proceed:
sprintf(line, "/proc/%d/maps", pid);
- f = fopen(line, "r");
+ f = fopen(line, "re");
if (!f) {
err = -errno;
pr_warn("usdt: failed to open '%s' to get base addr of '%s': %d\n",
@@ -954,8 +954,7 @@ struct bpf_link *usdt_manager_attach_usdt(struct usdt_manager *man, const struct
spec_map_fd = bpf_map__fd(man->specs_map);
ip_map_fd = bpf_map__fd(man->ip_to_spec_id_map);
- /* TODO: perform path resolution similar to uprobe's */
- fd = open(path, O_RDONLY);
+ fd = open(path, O_RDONLY | O_CLOEXEC);
if (fd < 0) {
err = -errno;
pr_warn("usdt: failed to open ELF binary '%s': %d\n", path, err);
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH bpf-next 2/2] libbpf: ensure FD >= 3 during bpf_map__reuse_fd()
2023-05-25 22:13 [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC Andrii Nakryiko
@ 2023-05-25 22:13 ` Andrii Nakryiko
2023-05-26 8:19 ` [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC Lennart Poettering
2023-05-26 10:10 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: Andrii Nakryiko @ 2023-05-25 22:13 UTC (permalink / raw)
To: bpf, ast, daniel, martin.lau; +Cc: lennart, Andrii Nakryiko
Improve bpf_map__reuse_fd() logic and ensure that dup'ed map FD is
"good" (>= 3) and has O_CLOEXEC flags. Use fcntl(F_DUPFD_CLOEXEC) for
that, similarly to ensure_good_fd() helper we already use in low-level
APIs that work with bpf() syscall.
Suggested-by: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/libbpf.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 60ef4c5e3bee..47632606b06d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4414,18 +4414,17 @@ int bpf_map__reuse_fd(struct bpf_map *map, int fd)
if (!new_name)
return libbpf_err(-errno);
- new_fd = open("/", O_RDONLY | O_CLOEXEC);
+ /*
+ * Like dup(), but make sure new FD is >= 3 and has O_CLOEXEC set.
+ * This is similar to what we do in ensure_good_fd(), but without
+ * closing original FD.
+ */
+ new_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
if (new_fd < 0) {
err = -errno;
goto err_free_new_name;
}
- new_fd = dup3(fd, new_fd, O_CLOEXEC);
- if (new_fd < 0) {
- err = -errno;
- goto err_close_new_fd;
- }
-
err = zclose(map->fd);
if (err) {
err = -errno;
--
2.34.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC
2023-05-25 22:13 [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC Andrii Nakryiko
2023-05-25 22:13 ` [PATCH bpf-next 2/2] libbpf: ensure FD >= 3 during bpf_map__reuse_fd() Andrii Nakryiko
@ 2023-05-26 8:19 ` Lennart Poettering
2023-05-26 9:19 ` Daniel Borkmann
2023-05-26 10:10 ` patchwork-bot+netdevbpf
2 siblings, 1 reply; 5+ messages in thread
From: Lennart Poettering @ 2023-05-26 8:19 UTC (permalink / raw)
To: Andrii Nakryiko; +Cc: bpf, ast, daniel, martin.lau
On Do, 25.05.23 15:13, Andrii Nakryiko (andrii@kernel.org) wrote:
> Make sure that libbpf code always gets FD with O_CLOEXEC flag set,
> regardless if file is open through open() or fopen(). For the latter
> this means to add "e" to mode string, which is supported since pretty
> ancient glibc v2.7.
>
> I also dropped outdated TODO comment in usdt.c, which was already completed.
>
> Suggested-by: Lennart Poettering <lennart@poettering.net>
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---
> tools/lib/bpf/btf.c | 2 +-
> tools/lib/bpf/libbpf.c | 6 +++---
> tools/lib/bpf/libbpf_probes.c | 2 +-
> tools/lib/bpf/usdt.c | 5 ++---
> 4 files changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
> index 0a2c079244b6..8484b563b53d 100644
> --- a/tools/lib/bpf/btf.c
> +++ b/tools/lib/bpf/btf.c
> @@ -1064,7 +1064,7 @@ static struct btf *btf_parse_raw(const char *path, struct btf *base_btf)
> int err = 0;
> long sz;
>
> - f = fopen(path, "rb");
> + f = fopen(path, "rbe");
You might as well drop the "b". That's a thing only on non-POSIX
systems. So unless you want to support windows with this, you can drop
it with zero effect.
Thanks for doing this, much appreciated!
Lennart
--
Lennart Poettering, Berlin
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC
2023-05-26 8:19 ` [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC Lennart Poettering
@ 2023-05-26 9:19 ` Daniel Borkmann
0 siblings, 0 replies; 5+ messages in thread
From: Daniel Borkmann @ 2023-05-26 9:19 UTC (permalink / raw)
To: Lennart Poettering, Andrii Nakryiko; +Cc: bpf, ast, martin.lau
On 5/26/23 10:19 AM, Lennart Poettering wrote:
> On Do, 25.05.23 15:13, Andrii Nakryiko (andrii@kernel.org) wrote:
>
>> Make sure that libbpf code always gets FD with O_CLOEXEC flag set,
>> regardless if file is open through open() or fopen(). For the latter
>> this means to add "e" to mode string, which is supported since pretty
>> ancient glibc v2.7.
>>
>> I also dropped outdated TODO comment in usdt.c, which was already completed.
>>
>> Suggested-by: Lennart Poettering <lennart@poettering.net>
>> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
>> ---
>> tools/lib/bpf/btf.c | 2 +-
>> tools/lib/bpf/libbpf.c | 6 +++---
>> tools/lib/bpf/libbpf_probes.c | 2 +-
>> tools/lib/bpf/usdt.c | 5 ++---
>> 4 files changed, 7 insertions(+), 8 deletions(-)
>>
>> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c
>> index 0a2c079244b6..8484b563b53d 100644
>> --- a/tools/lib/bpf/btf.c
>> +++ b/tools/lib/bpf/btf.c
>> @@ -1064,7 +1064,7 @@ static struct btf *btf_parse_raw(const char *path, struct btf *base_btf)
>> int err = 0;
>> long sz;
>>
>> - f = fopen(path, "rb");
>> + f = fopen(path, "rbe");
>
> You might as well drop the "b". That's a thing only on non-POSIX
> systems. So unless you want to support windows with this, you can drop
> it with zero effect.
Iiuc, the library is also imported by the 'ebpf for windows' project [0],
so we might need to keep the 'b' intact in that case.
Thanks,
Daniel
[0] https://github.com/microsoft/ebpf-for-windows/#architectural-overview
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC
2023-05-25 22:13 [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC Andrii Nakryiko
2023-05-25 22:13 ` [PATCH bpf-next 2/2] libbpf: ensure FD >= 3 during bpf_map__reuse_fd() Andrii Nakryiko
2023-05-26 8:19 ` [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC Lennart Poettering
@ 2023-05-26 10:10 ` patchwork-bot+netdevbpf
2 siblings, 0 replies; 5+ messages in thread
From: patchwork-bot+netdevbpf @ 2023-05-26 10:10 UTC (permalink / raw)
To: Andrii Nakryiko; +Cc: bpf, ast, daniel, martin.lau, lennart
Hello:
This series was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:
On Thu, 25 May 2023 15:13:10 -0700 you wrote:
> Make sure that libbpf code always gets FD with O_CLOEXEC flag set,
> regardless if file is open through open() or fopen(). For the latter
> this means to add "e" to mode string, which is supported since pretty
> ancient glibc v2.7.
>
> I also dropped outdated TODO comment in usdt.c, which was already completed.
>
> [...]
Here is the summary with links:
- [bpf-next,1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC
https://git.kernel.org/bpf/bpf-next/c/59842c5451fe
- [bpf-next,2/2] libbpf: ensure FD >= 3 during bpf_map__reuse_fd()
https://git.kernel.org/bpf/bpf-next/c/4aadd2920b81
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] 5+ messages in thread
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2023-05-26 8:19 ` [PATCH bpf-next 1/2] libbpf: ensure libbpf always opens files with O_CLOEXEC Lennart Poettering
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