* [bpf-next v9 1/2] bpf: Add bpf_copy_from_user_str kfunc
@ 2024-08-23 18:48 Jordan Rome
2024-08-23 18:48 ` [bpf-next v9 2/2] bpf: Add tests for " Jordan Rome
0 siblings, 1 reply; 6+ messages in thread
From: Jordan Rome @ 2024-08-23 18:48 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Kernel Team, sinquersw
This adds a kfunc wrapper around strncpy_from_user,
which can be called from sleepable BPF programs.
This matches the non-sleepable 'bpf_probe_read_user_str'
helper except it includes an additional 'flags'
param, which allows consumers to clear the entire
destination buffer on success or failure.
Signed-off-by: Jordan Rome <linux@jordanrome.com>
---
include/uapi/linux/bpf.h | 9 ++++++++
kernel/bpf/helpers.c | 42 ++++++++++++++++++++++++++++++++++
tools/include/uapi/linux/bpf.h | 9 ++++++++
3 files changed, 60 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index e05b39e39c3f..d015fdcdad3a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -7513,4 +7513,13 @@ struct bpf_iter_num {
__u64 __opaque[1];
} __attribute__((aligned(8)));
+/*
+ * Flags to control bpf_copy_from_user_str() behaviour.
+ * - BPF_F_PAD_ZEROS: Pad destination buffer with zeros. (See the respective
+ * helper documentation for details.)
+ */
+enum bpf_kfunc_flags {
+ BPF_F_PAD_ZEROS = (1ULL << 0),
+};
+
#endif /* _UAPI__LINUX_BPF_H__ */
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index d02ae323996b..5f065804c096 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2939,6 +2939,47 @@ __bpf_kfunc void bpf_iter_bits_destroy(struct bpf_iter_bits *it)
bpf_mem_free(&bpf_global_ma, kit->bits);
}
+/**
+ * bpf_copy_from_user_str() - Copy a string from an unsafe user address
+ * @dst: Destination address, in kernel space. This buffer must be at
+ * least @dst__sz bytes long.
+ * @dst__sz: Maximum number of bytes to copy, including the trailing NUL.
+ * @unsafe_ptr__ign: Source address, in user space.
+ * @flags: The only supported flag is BPF_F_PAD_ZEROS
+ *
+ * Copies a NUL-terminated string from userspace to BPF space. If user string is
+ * too long this will still ensure zero termination in the dst buffer unless
+ * buffer size is 0.
+ *
+ * If BPF_F_PAD_ZEROS flag is set, memset the tail of @dst to 0 on success and
+ * memset all of @dst on failure.
+ */
+__bpf_kfunc int bpf_copy_from_user_str(void *dst, u32 dst__sz, const void __user *unsafe_ptr__ign, u64 flags)
+{
+ int ret;
+
+ if (unlikely(flags & ~BPF_F_PAD_ZEROS))
+ return -EINVAL;
+
+ if (unlikely(!dst__sz))
+ return 0;
+
+ ret = strncpy_from_user(dst, unsafe_ptr__ign, dst__sz - 1);
+ if (ret < 0) {
+ if (flags & BPF_F_PAD_ZEROS)
+ memset((char *)dst, 0, dst__sz);
+
+ return ret;
+ }
+
+ if (flags & BPF_F_PAD_ZEROS)
+ memset((char *)dst + ret, 0, dst__sz - ret);
+ else
+ ((char *)dst)[ret] = '\0';
+
+ return ret + 1;
+}
+
__bpf_kfunc_end_defs();
BTF_KFUNCS_START(generic_btf_ids)
@@ -3024,6 +3065,7 @@ BTF_ID_FLAGS(func, bpf_preempt_enable)
BTF_ID_FLAGS(func, bpf_iter_bits_new, KF_ITER_NEW)
BTF_ID_FLAGS(func, bpf_iter_bits_next, KF_ITER_NEXT | KF_RET_NULL)
BTF_ID_FLAGS(func, bpf_iter_bits_destroy, KF_ITER_DESTROY)
+BTF_ID_FLAGS(func, bpf_copy_from_user_str, KF_SLEEPABLE)
BTF_KFUNCS_END(common_btf_ids)
static const struct btf_kfunc_id_set common_kfunc_set = {
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index e05b39e39c3f..d015fdcdad3a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -7513,4 +7513,13 @@ struct bpf_iter_num {
__u64 __opaque[1];
} __attribute__((aligned(8)));
+/*
+ * Flags to control bpf_copy_from_user_str() behaviour.
+ * - BPF_F_PAD_ZEROS: Pad destination buffer with zeros. (See the respective
+ * helper documentation for details.)
+ */
+enum bpf_kfunc_flags {
+ BPF_F_PAD_ZEROS = (1ULL << 0),
+};
+
#endif /* _UAPI__LINUX_BPF_H__ */
--
2.43.5
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [bpf-next v9 2/2] bpf: Add tests for bpf_copy_from_user_str kfunc
2024-08-23 18:48 [bpf-next v9 1/2] bpf: Add bpf_copy_from_user_str kfunc Jordan Rome
@ 2024-08-23 18:48 ` Jordan Rome
2024-08-23 18:52 ` Alexei Starovoitov
2024-08-23 18:59 ` Andrii Nakryiko
0 siblings, 2 replies; 6+ messages in thread
From: Jordan Rome @ 2024-08-23 18:48 UTC (permalink / raw)
To: bpf
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Kernel Team, sinquersw
This adds tests for both the happy path and
the error path.
Signed-off-by: Jordan Rome <linux@jordanrome.com>
---
.../selftests/bpf/prog_tests/attach_probe.c | 8 ++-
.../selftests/bpf/prog_tests/read_vsyscall.c | 1 +
.../selftests/bpf/progs/read_vsyscall.c | 9 ++-
.../selftests/bpf/progs/test_attach_probe.c | 64 ++++++++++++++++++-
4 files changed, 75 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
index 7175af39134f..329c7862b52d 100644
--- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
+++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
@@ -283,9 +283,11 @@ static void test_uprobe_sleepable(struct test_attach_probe *skel)
trigger_func3();
ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res");
- ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res");
- ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res");
- ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res");
+ ASSERT_EQ(skel->bss->uprobe_byname3_str_sleepable_res, 10, "check_uprobe_byname3_str_sleepable_res");
+ ASSERT_EQ(skel->bss->uprobe_byname3_res, 11, "check_uprobe_byname3_res");
+ ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 12, "check_uretprobe_byname3_sleepable_res");
+ ASSERT_EQ(skel->bss->uretprobe_byname3_str_sleepable_res, 13, "check_uretprobe_byname3_str_sleepable_res");
+ ASSERT_EQ(skel->bss->uretprobe_byname3_res, 14, "check_uretprobe_byname3_res");
}
void test_attach_probe(void)
diff --git a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
index 3405923fe4e6..c7b9ba8b1d06 100644
--- a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
@@ -23,6 +23,7 @@ struct read_ret_desc {
{ .name = "probe_read_user_str", .ret = -EFAULT },
{ .name = "copy_from_user", .ret = -EFAULT },
{ .name = "copy_from_user_task", .ret = -EFAULT },
+ { .name = "copy_from_user_str", .ret = -EFAULT },
};
void test_read_vsyscall(void)
diff --git a/tools/testing/selftests/bpf/progs/read_vsyscall.c b/tools/testing/selftests/bpf/progs/read_vsyscall.c
index 986f96687ae1..39ebef430059 100644
--- a/tools/testing/selftests/bpf/progs/read_vsyscall.c
+++ b/tools/testing/selftests/bpf/progs/read_vsyscall.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2024. Huawei Technologies Co., Ltd */
+#include "vmlinux.h"
#include <linux/types.h>
#include <bpf/bpf_helpers.h>
@@ -7,10 +8,15 @@
int target_pid = 0;
void *user_ptr = 0;
-int read_ret[8];
+int read_ret[9];
char _license[] SEC("license") = "GPL";
+/*
+ * This is the only kfunc, the others are helpers
+ */
+int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym;
+
SEC("fentry/" SYS_PREFIX "sys_nanosleep")
int do_probe_read(void *ctx)
{
@@ -40,6 +46,7 @@ int do_copy_from_user(void *ctx)
read_ret[6] = bpf_copy_from_user(buf, sizeof(buf), user_ptr);
read_ret[7] = bpf_copy_from_user_task(buf, sizeof(buf), user_ptr,
bpf_get_current_task_btf(), 0);
+ read_ret[8] = bpf_copy_from_user_str((char *)buf, sizeof(buf), user_ptr, 0);
return 0;
}
diff --git a/tools/testing/selftests/bpf/progs/test_attach_probe.c b/tools/testing/selftests/bpf/progs/test_attach_probe.c
index 68466a6ad18c..0b16502726f8 100644
--- a/tools/testing/selftests/bpf/progs/test_attach_probe.c
+++ b/tools/testing/selftests/bpf/progs/test_attach_probe.c
@@ -5,6 +5,7 @@
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_core_read.h>
+#include <errno.h>
#include "bpf_misc.h"
int kprobe2_res = 0;
@@ -14,10 +15,15 @@ int uretprobe_byname_res = 0;
int uprobe_byname2_res = 0;
int uretprobe_byname2_res = 0;
int uprobe_byname3_sleepable_res = 0;
+int uprobe_byname3_str_sleepable_res = 0;
int uprobe_byname3_res = 0;
int uretprobe_byname3_sleepable_res = 0;
+int uretprobe_byname3_str_sleepable_res = 0;
int uretprobe_byname3_res = 0;
void *user_ptr = 0;
+u32 dynamic_sz = 1;
+
+int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym;
SEC("ksyscall/nanosleep")
int BPF_KSYSCALL(handle_kprobe_auto, struct __kernel_timespec *req, struct __kernel_timespec *rem)
@@ -87,11 +93,61 @@ static __always_inline bool verify_sleepable_user_copy(void)
return bpf_strncmp(data, sizeof(data), "test_data") == 0;
}
+static __always_inline bool verify_sleepable_user_copy_str(void)
+{
+ int ret;
+ char data_long[20];
+ char data_long_pad[20];
+ char data_long_err[20];
+ char data_short[4];
+ char data_short_pad[4];
+
+ ret = bpf_copy_from_user_str(data_short, sizeof(data_short), user_ptr, 0);
+
+ if (bpf_strncmp(data_short, 4, "tes\0") != 0 || ret != 4)
+ return false;
+
+ ret = bpf_copy_from_user_str(data_short_pad, sizeof(data_short_pad), user_ptr, BPF_F_PAD_ZEROS);
+
+ if (bpf_strncmp(data_short, 4, "tes\0") != 0 || ret != 4)
+ return false;
+
+ // Make sure this passes the verifier
+ ret = bpf_copy_from_user_str(data_long, dynamic_sz &= sizeof(data_long), user_ptr, 0);
+
+ if (ret != 0)
+ return false;
+
+ ret = bpf_copy_from_user_str(data_long, sizeof(data_long), user_ptr, 0);
+
+ if (bpf_strncmp(data_long, 10, "test_data\0") != 0 || ret != 10)
+ return false;
+
+ ret = bpf_copy_from_user_str(data_long_pad, sizeof(data_long_pad), user_ptr, BPF_F_PAD_ZEROS);
+
+ if (bpf_strncmp(data_long_pad, 10, "test_data\0") != 0 || ret != 10 || data_long_pad[19] != '\0')
+ return false;
+
+ ret = bpf_copy_from_user_str(data_long_err, sizeof(data_long_err), (void *)data_long, BPF_F_PAD_ZEROS);
+
+ if (ret > 0 || data_long_err[19] != '\0')
+ return false;
+
+ ret = bpf_copy_from_user_str(data_long, sizeof(data_long), user_ptr, 2);
+
+ if (ret != -EINVAL)
+ return false;
+
+ return true;
+}
+
SEC("uprobe.s//proc/self/exe:trigger_func3")
int handle_uprobe_byname3_sleepable(struct pt_regs *ctx)
{
if (verify_sleepable_user_copy())
uprobe_byname3_sleepable_res = 9;
+ if (verify_sleepable_user_copy_str())
+ uprobe_byname3_str_sleepable_res = 10;
return 0;
}
@@ -102,7 +158,7 @@ int handle_uprobe_byname3_sleepable(struct pt_regs *ctx)
SEC("uprobe//proc/self/exe:trigger_func3")
int handle_uprobe_byname3(struct pt_regs *ctx)
{
- uprobe_byname3_res = 10;
+ uprobe_byname3_res = 11;
return 0;
}
@@ -110,14 +166,16 @@ SEC("uretprobe.s//proc/self/exe:trigger_func3")
int handle_uretprobe_byname3_sleepable(struct pt_regs *ctx)
{
if (verify_sleepable_user_copy())
- uretprobe_byname3_sleepable_res = 11;
+ uretprobe_byname3_sleepable_res = 12;
+ if (verify_sleepable_user_copy_str())
+ uretprobe_byname3_str_sleepable_res = 13;
return 0;
}
SEC("uretprobe//proc/self/exe:trigger_func3")
int handle_uretprobe_byname3(struct pt_regs *ctx)
{
- uretprobe_byname3_res = 12;
+ uretprobe_byname3_res = 14;
return 0;
}
--
2.43.5
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [bpf-next v9 2/2] bpf: Add tests for bpf_copy_from_user_str kfunc
2024-08-23 18:48 ` [bpf-next v9 2/2] bpf: Add tests for " Jordan Rome
@ 2024-08-23 18:52 ` Alexei Starovoitov
2024-08-23 18:55 ` Jordan Rome
2024-08-23 18:59 ` Andrii Nakryiko
1 sibling, 1 reply; 6+ messages in thread
From: Alexei Starovoitov @ 2024-08-23 18:52 UTC (permalink / raw)
To: Jordan Rome
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Kernel Team, Kui-Feng Lee
On Fri, Aug 23, 2024 at 11:49 AM Jordan Rome <linux@jordanrome.com> wrote:
>
> +u32 dynamic_sz = 1;
..
> +
> + // Make sure this passes the verifier
> + ret = bpf_copy_from_user_str(data_long, dynamic_sz &= sizeof(data_long), user_ptr, 0);
Did you really mean to &= into the global variable while passing it as
an argument?
And the compiler didn't warn?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [bpf-next v9 2/2] bpf: Add tests for bpf_copy_from_user_str kfunc
2024-08-23 18:52 ` Alexei Starovoitov
@ 2024-08-23 18:55 ` Jordan Rome
0 siblings, 0 replies; 6+ messages in thread
From: Jordan Rome @ 2024-08-23 18:55 UTC (permalink / raw)
To: Alexei Starovoitov
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Kernel Team, Kui-Feng Lee
On Fri, Aug 23, 2024 at 2:52 PM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Fri, Aug 23, 2024 at 11:49 AM Jordan Rome <linux@jordanrome.com> wrote:
> >
> > +u32 dynamic_sz = 1;
>
> ..
>
> > +
> > + // Make sure this passes the verifier
> > + ret = bpf_copy_from_user_str(data_long, dynamic_sz &= sizeof(data_long), user_ptr, 0);
>
> Did you really mean to &= into the global variable while passing it as
> an argument?
>
> And the compiler didn't warn?
The compiler didn't warn but no, I meant to do just '&' - here comes v10!
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [bpf-next v9 2/2] bpf: Add tests for bpf_copy_from_user_str kfunc
2024-08-23 18:48 ` [bpf-next v9 2/2] bpf: Add tests for " Jordan Rome
2024-08-23 18:52 ` Alexei Starovoitov
@ 2024-08-23 18:59 ` Andrii Nakryiko
2024-08-23 19:05 ` Jordan Rome
1 sibling, 1 reply; 6+ messages in thread
From: Andrii Nakryiko @ 2024-08-23 18:59 UTC (permalink / raw)
To: Jordan Rome
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Kernel Team, sinquersw
On Fri, Aug 23, 2024 at 11:49 AM Jordan Rome <linux@jordanrome.com> wrote:
>
> This adds tests for both the happy path and
> the error path.
>
> Signed-off-by: Jordan Rome <linux@jordanrome.com>
> ---
> .../selftests/bpf/prog_tests/attach_probe.c | 8 ++-
> .../selftests/bpf/prog_tests/read_vsyscall.c | 1 +
> .../selftests/bpf/progs/read_vsyscall.c | 9 ++-
> .../selftests/bpf/progs/test_attach_probe.c | 64 ++++++++++++++++++-
> 4 files changed, 75 insertions(+), 7 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> index 7175af39134f..329c7862b52d 100644
> --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> @@ -283,9 +283,11 @@ static void test_uprobe_sleepable(struct test_attach_probe *skel)
> trigger_func3();
>
> ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res");
> - ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res");
> - ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res");
> - ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res");
> + ASSERT_EQ(skel->bss->uprobe_byname3_str_sleepable_res, 10, "check_uprobe_byname3_str_sleepable_res");
> + ASSERT_EQ(skel->bss->uprobe_byname3_res, 11, "check_uprobe_byname3_res");
> + ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 12, "check_uretprobe_byname3_sleepable_res");
> + ASSERT_EQ(skel->bss->uretprobe_byname3_str_sleepable_res, 13, "check_uretprobe_byname3_str_sleepable_res");
> + ASSERT_EQ(skel->bss->uretprobe_byname3_res, 14, "check_uretprobe_byname3_res");
> }
>
> void test_attach_probe(void)
> diff --git a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
> index 3405923fe4e6..c7b9ba8b1d06 100644
> --- a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
> +++ b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
> @@ -23,6 +23,7 @@ struct read_ret_desc {
> { .name = "probe_read_user_str", .ret = -EFAULT },
> { .name = "copy_from_user", .ret = -EFAULT },
> { .name = "copy_from_user_task", .ret = -EFAULT },
> + { .name = "copy_from_user_str", .ret = -EFAULT },
> };
>
> void test_read_vsyscall(void)
> diff --git a/tools/testing/selftests/bpf/progs/read_vsyscall.c b/tools/testing/selftests/bpf/progs/read_vsyscall.c
> index 986f96687ae1..39ebef430059 100644
> --- a/tools/testing/selftests/bpf/progs/read_vsyscall.c
> +++ b/tools/testing/selftests/bpf/progs/read_vsyscall.c
> @@ -1,5 +1,6 @@
> // SPDX-License-Identifier: GPL-2.0
> /* Copyright (C) 2024. Huawei Technologies Co., Ltd */
> +#include "vmlinux.h"
> #include <linux/types.h>
> #include <bpf/bpf_helpers.h>
>
> @@ -7,10 +8,15 @@
>
> int target_pid = 0;
> void *user_ptr = 0;
> -int read_ret[8];
> +int read_ret[9];
>
> char _license[] SEC("license") = "GPL";
>
> +/*
> + * This is the only kfunc, the others are helpers
> + */
> +int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym;
> +
> SEC("fentry/" SYS_PREFIX "sys_nanosleep")
> int do_probe_read(void *ctx)
> {
> @@ -40,6 +46,7 @@ int do_copy_from_user(void *ctx)
> read_ret[6] = bpf_copy_from_user(buf, sizeof(buf), user_ptr);
> read_ret[7] = bpf_copy_from_user_task(buf, sizeof(buf), user_ptr,
> bpf_get_current_task_btf(), 0);
> + read_ret[8] = bpf_copy_from_user_str((char *)buf, sizeof(buf), user_ptr, 0);
>
> return 0;
> }
> diff --git a/tools/testing/selftests/bpf/progs/test_attach_probe.c b/tools/testing/selftests/bpf/progs/test_attach_probe.c
> index 68466a6ad18c..0b16502726f8 100644
> --- a/tools/testing/selftests/bpf/progs/test_attach_probe.c
> +++ b/tools/testing/selftests/bpf/progs/test_attach_probe.c
> @@ -5,6 +5,7 @@
> #include <bpf/bpf_helpers.h>
> #include <bpf/bpf_tracing.h>
> #include <bpf/bpf_core_read.h>
> +#include <errno.h>
> #include "bpf_misc.h"
>
> int kprobe2_res = 0;
> @@ -14,10 +15,15 @@ int uretprobe_byname_res = 0;
> int uprobe_byname2_res = 0;
> int uretprobe_byname2_res = 0;
> int uprobe_byname3_sleepable_res = 0;
> +int uprobe_byname3_str_sleepable_res = 0;
> int uprobe_byname3_res = 0;
> int uretprobe_byname3_sleepable_res = 0;
> +int uretprobe_byname3_str_sleepable_res = 0;
> int uretprobe_byname3_res = 0;
> void *user_ptr = 0;
> +u32 dynamic_sz = 1;
> +
> +int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym;
>
> SEC("ksyscall/nanosleep")
> int BPF_KSYSCALL(handle_kprobe_auto, struct __kernel_timespec *req, struct __kernel_timespec *rem)
> @@ -87,11 +93,61 @@ static __always_inline bool verify_sleepable_user_copy(void)
> return bpf_strncmp(data, sizeof(data), "test_data") == 0;
> }
>
> +static __always_inline bool verify_sleepable_user_copy_str(void)
> +{
> + int ret;
> + char data_long[20];
> + char data_long_pad[20];
> + char data_long_err[20];
> + char data_short[4];
> + char data_short_pad[4];
> +
> + ret = bpf_copy_from_user_str(data_short, sizeof(data_short), user_ptr, 0);
> +
> + if (bpf_strncmp(data_short, 4, "tes\0") != 0 || ret != 4)
> + return false;
> +
> + ret = bpf_copy_from_user_str(data_short_pad, sizeof(data_short_pad), user_ptr, BPF_F_PAD_ZEROS);
> +
> + if (bpf_strncmp(data_short, 4, "tes\0") != 0 || ret != 4)
> + return false;
> +
> + // Make sure this passes the verifier
also please don't use C++-style comments
> + ret = bpf_copy_from_user_str(data_long, dynamic_sz &= sizeof(data_long), user_ptr, 0);
> +
> + if (ret != 0)
> + return false;
> +
> + ret = bpf_copy_from_user_str(data_long, sizeof(data_long), user_ptr, 0);
> +
> + if (bpf_strncmp(data_long, 10, "test_data\0") != 0 || ret != 10)
> + return false;
> +
> + ret = bpf_copy_from_user_str(data_long_pad, sizeof(data_long_pad), user_ptr, BPF_F_PAD_ZEROS);
> +
> + if (bpf_strncmp(data_long_pad, 10, "test_data\0") != 0 || ret != 10 || data_long_pad[19] != '\0')
> + return false;
> +
> + ret = bpf_copy_from_user_str(data_long_err, sizeof(data_long_err), (void *)data_long, BPF_F_PAD_ZEROS);
> +
> + if (ret > 0 || data_long_err[19] != '\0')
> + return false;
> +
> + ret = bpf_copy_from_user_str(data_long, sizeof(data_long), user_ptr, 2);
> +
> + if (ret != -EINVAL)
> + return false;
> +
> + return true;
> +}
> +
> SEC("uprobe.s//proc/self/exe:trigger_func3")
> int handle_uprobe_byname3_sleepable(struct pt_regs *ctx)
> {
> if (verify_sleepable_user_copy())
> uprobe_byname3_sleepable_res = 9;
> + if (verify_sleepable_user_copy_str())
> + uprobe_byname3_str_sleepable_res = 10;
> return 0;
> }
>
> @@ -102,7 +158,7 @@ int handle_uprobe_byname3_sleepable(struct pt_regs *ctx)
> SEC("uprobe//proc/self/exe:trigger_func3")
> int handle_uprobe_byname3(struct pt_regs *ctx)
> {
> - uprobe_byname3_res = 10;
> + uprobe_byname3_res = 11;
> return 0;
> }
>
> @@ -110,14 +166,16 @@ SEC("uretprobe.s//proc/self/exe:trigger_func3")
> int handle_uretprobe_byname3_sleepable(struct pt_regs *ctx)
> {
> if (verify_sleepable_user_copy())
> - uretprobe_byname3_sleepable_res = 11;
> + uretprobe_byname3_sleepable_res = 12;
> + if (verify_sleepable_user_copy_str())
> + uretprobe_byname3_str_sleepable_res = 13;
> return 0;
> }
>
> SEC("uretprobe//proc/self/exe:trigger_func3")
> int handle_uretprobe_byname3(struct pt_regs *ctx)
> {
> - uretprobe_byname3_res = 12;
> + uretprobe_byname3_res = 14;
> return 0;
> }
>
> --
> 2.43.5
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [bpf-next v9 2/2] bpf: Add tests for bpf_copy_from_user_str kfunc
2024-08-23 18:59 ` Andrii Nakryiko
@ 2024-08-23 19:05 ` Jordan Rome
0 siblings, 0 replies; 6+ messages in thread
From: Jordan Rome @ 2024-08-23 19:05 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: bpf, Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Kernel Team, sinquersw
On Fri, Aug 23, 2024 at 3:00 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Fri, Aug 23, 2024 at 11:49 AM Jordan Rome <linux@jordanrome.com> wrote:
> >
> > This adds tests for both the happy path and
> > the error path.
> >
> > Signed-off-by: Jordan Rome <linux@jordanrome.com>
> > ---
> > .../selftests/bpf/prog_tests/attach_probe.c | 8 ++-
> > .../selftests/bpf/prog_tests/read_vsyscall.c | 1 +
> > .../selftests/bpf/progs/read_vsyscall.c | 9 ++-
> > .../selftests/bpf/progs/test_attach_probe.c | 64 ++++++++++++++++++-
> > 4 files changed, 75 insertions(+), 7 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> > index 7175af39134f..329c7862b52d 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> > @@ -283,9 +283,11 @@ static void test_uprobe_sleepable(struct test_attach_probe *skel)
> > trigger_func3();
> >
> > ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res");
> > - ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res");
> > - ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res");
> > - ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res");
> > + ASSERT_EQ(skel->bss->uprobe_byname3_str_sleepable_res, 10, "check_uprobe_byname3_str_sleepable_res");
> > + ASSERT_EQ(skel->bss->uprobe_byname3_res, 11, "check_uprobe_byname3_res");
> > + ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 12, "check_uretprobe_byname3_sleepable_res");
> > + ASSERT_EQ(skel->bss->uretprobe_byname3_str_sleepable_res, 13, "check_uretprobe_byname3_str_sleepable_res");
> > + ASSERT_EQ(skel->bss->uretprobe_byname3_res, 14, "check_uretprobe_byname3_res");
> > }
> >
> > void test_attach_probe(void)
> > diff --git a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
> > index 3405923fe4e6..c7b9ba8b1d06 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c
> > @@ -23,6 +23,7 @@ struct read_ret_desc {
> > { .name = "probe_read_user_str", .ret = -EFAULT },
> > { .name = "copy_from_user", .ret = -EFAULT },
> > { .name = "copy_from_user_task", .ret = -EFAULT },
> > + { .name = "copy_from_user_str", .ret = -EFAULT },
> > };
> >
> > void test_read_vsyscall(void)
> > diff --git a/tools/testing/selftests/bpf/progs/read_vsyscall.c b/tools/testing/selftests/bpf/progs/read_vsyscall.c
> > index 986f96687ae1..39ebef430059 100644
> > --- a/tools/testing/selftests/bpf/progs/read_vsyscall.c
> > +++ b/tools/testing/selftests/bpf/progs/read_vsyscall.c
> > @@ -1,5 +1,6 @@
> > // SPDX-License-Identifier: GPL-2.0
> > /* Copyright (C) 2024. Huawei Technologies Co., Ltd */
> > +#include "vmlinux.h"
> > #include <linux/types.h>
> > #include <bpf/bpf_helpers.h>
> >
> > @@ -7,10 +8,15 @@
> >
> > int target_pid = 0;
> > void *user_ptr = 0;
> > -int read_ret[8];
> > +int read_ret[9];
> >
> > char _license[] SEC("license") = "GPL";
> >
> > +/*
> > + * This is the only kfunc, the others are helpers
> > + */
> > +int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym;
> > +
> > SEC("fentry/" SYS_PREFIX "sys_nanosleep")
> > int do_probe_read(void *ctx)
> > {
> > @@ -40,6 +46,7 @@ int do_copy_from_user(void *ctx)
> > read_ret[6] = bpf_copy_from_user(buf, sizeof(buf), user_ptr);
> > read_ret[7] = bpf_copy_from_user_task(buf, sizeof(buf), user_ptr,
> > bpf_get_current_task_btf(), 0);
> > + read_ret[8] = bpf_copy_from_user_str((char *)buf, sizeof(buf), user_ptr, 0);
> >
> > return 0;
> > }
> > diff --git a/tools/testing/selftests/bpf/progs/test_attach_probe.c b/tools/testing/selftests/bpf/progs/test_attach_probe.c
> > index 68466a6ad18c..0b16502726f8 100644
> > --- a/tools/testing/selftests/bpf/progs/test_attach_probe.c
> > +++ b/tools/testing/selftests/bpf/progs/test_attach_probe.c
> > @@ -5,6 +5,7 @@
> > #include <bpf/bpf_helpers.h>
> > #include <bpf/bpf_tracing.h>
> > #include <bpf/bpf_core_read.h>
> > +#include <errno.h>
> > #include "bpf_misc.h"
> >
> > int kprobe2_res = 0;
> > @@ -14,10 +15,15 @@ int uretprobe_byname_res = 0;
> > int uprobe_byname2_res = 0;
> > int uretprobe_byname2_res = 0;
> > int uprobe_byname3_sleepable_res = 0;
> > +int uprobe_byname3_str_sleepable_res = 0;
> > int uprobe_byname3_res = 0;
> > int uretprobe_byname3_sleepable_res = 0;
> > +int uretprobe_byname3_str_sleepable_res = 0;
> > int uretprobe_byname3_res = 0;
> > void *user_ptr = 0;
> > +u32 dynamic_sz = 1;
> > +
> > +int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym;
> >
> > SEC("ksyscall/nanosleep")
> > int BPF_KSYSCALL(handle_kprobe_auto, struct __kernel_timespec *req, struct __kernel_timespec *rem)
> > @@ -87,11 +93,61 @@ static __always_inline bool verify_sleepable_user_copy(void)
> > return bpf_strncmp(data, sizeof(data), "test_data") == 0;
> > }
> >
> > +static __always_inline bool verify_sleepable_user_copy_str(void)
> > +{
> > + int ret;
> > + char data_long[20];
> > + char data_long_pad[20];
> > + char data_long_err[20];
> > + char data_short[4];
> > + char data_short_pad[4];
> > +
> > + ret = bpf_copy_from_user_str(data_short, sizeof(data_short), user_ptr, 0);
> > +
> > + if (bpf_strncmp(data_short, 4, "tes\0") != 0 || ret != 4)
> > + return false;
> > +
> > + ret = bpf_copy_from_user_str(data_short_pad, sizeof(data_short_pad), user_ptr, BPF_F_PAD_ZEROS);
> > +
> > + if (bpf_strncmp(data_short, 4, "tes\0") != 0 || ret != 4)
> > + return false;
> > +
> > + // Make sure this passes the verifier
>
> also please don't use C++-style comments
>
Good catch. Will fix.
> > + ret = bpf_copy_from_user_str(data_long, dynamic_sz &= sizeof(data_long), user_ptr, 0);
> > +
> > + if (ret != 0)
> > + return false;
> > +
> > + ret = bpf_copy_from_user_str(data_long, sizeof(data_long), user_ptr, 0);
> > +
> > + if (bpf_strncmp(data_long, 10, "test_data\0") != 0 || ret != 10)
> > + return false;
> > +
> > + ret = bpf_copy_from_user_str(data_long_pad, sizeof(data_long_pad), user_ptr, BPF_F_PAD_ZEROS);
> > +
> > + if (bpf_strncmp(data_long_pad, 10, "test_data\0") != 0 || ret != 10 || data_long_pad[19] != '\0')
> > + return false;
> > +
> > + ret = bpf_copy_from_user_str(data_long_err, sizeof(data_long_err), (void *)data_long, BPF_F_PAD_ZEROS);
> > +
> > + if (ret > 0 || data_long_err[19] != '\0')
> > + return false;
> > +
> > + ret = bpf_copy_from_user_str(data_long, sizeof(data_long), user_ptr, 2);
> > +
> > + if (ret != -EINVAL)
> > + return false;
> > +
> > + return true;
> > +}
> > +
> > SEC("uprobe.s//proc/self/exe:trigger_func3")
> > int handle_uprobe_byname3_sleepable(struct pt_regs *ctx)
> > {
> > if (verify_sleepable_user_copy())
> > uprobe_byname3_sleepable_res = 9;
> > + if (verify_sleepable_user_copy_str())
> > + uprobe_byname3_str_sleepable_res = 10;
> > return 0;
> > }
> >
> > @@ -102,7 +158,7 @@ int handle_uprobe_byname3_sleepable(struct pt_regs *ctx)
> > SEC("uprobe//proc/self/exe:trigger_func3")
> > int handle_uprobe_byname3(struct pt_regs *ctx)
> > {
> > - uprobe_byname3_res = 10;
> > + uprobe_byname3_res = 11;
> > return 0;
> > }
> >
> > @@ -110,14 +166,16 @@ SEC("uretprobe.s//proc/self/exe:trigger_func3")
> > int handle_uretprobe_byname3_sleepable(struct pt_regs *ctx)
> > {
> > if (verify_sleepable_user_copy())
> > - uretprobe_byname3_sleepable_res = 11;
> > + uretprobe_byname3_sleepable_res = 12;
> > + if (verify_sleepable_user_copy_str())
> > + uretprobe_byname3_str_sleepable_res = 13;
> > return 0;
> > }
> >
> > SEC("uretprobe//proc/self/exe:trigger_func3")
> > int handle_uretprobe_byname3(struct pt_regs *ctx)
> > {
> > - uretprobe_byname3_res = 12;
> > + uretprobe_byname3_res = 14;
> > return 0;
> > }
> >
> > --
> > 2.43.5
> >
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-08-23 19:05 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2024-08-23 18:48 [bpf-next v9 1/2] bpf: Add bpf_copy_from_user_str kfunc Jordan Rome
2024-08-23 18:48 ` [bpf-next v9 2/2] bpf: Add tests for " Jordan Rome
2024-08-23 18:52 ` Alexei Starovoitov
2024-08-23 18:55 ` Jordan Rome
2024-08-23 18:59 ` Andrii Nakryiko
2024-08-23 19:05 ` Jordan Rome
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