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| author | Joanne Koong <joannelkoong@gmail.com> | 2022-05-24 00:07:11 +0300 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2022-05-24 00:31:28 +0300 |
| commit | 34d4ef5775f776ec4b0d53a02d588bf3195cada6 (patch) | |
| tree | 4d71bdf2f9ea5fafa45995ae59d4893eebd1c26c /include/uapi | |
| parent | 13bbbfbea7598ea9f8d9c3d73bf053bb57f9c4b2 (diff) | |
| download | linux-34d4ef5775f776ec4b0d53a02d588bf3195cada6.tar.xz | |
bpf: Add dynptr data slices
This patch adds a new helper function
void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len);
which returns a pointer to the underlying data of a dynptr. *len*
must be a statically known value. The bpf program may access the returned
data slice as a normal buffer (eg can do direct reads and writes), since
the verifier associates the length with the returned pointer, and
enforces that no out of bounds accesses occur.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220523210712.3641569-6-joannelkoong@gmail.com
Diffstat (limited to 'include/uapi')
| -rw-r--r-- | include/uapi/linux/bpf.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index efe2505650e6..f4009dbdf62d 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5238,6 +5238,17 @@ union bpf_attr { * 0 on success, -E2BIG if *offset* + *len* exceeds the length * of *dst*'s data, -EINVAL if *dst* is an invalid dynptr or if *dst* * is a read-only dynptr. + * + * void *bpf_dynptr_data(struct bpf_dynptr *ptr, u32 offset, u32 len) + * Description + * Get a pointer to the underlying dynptr data. + * + * *len* must be a statically known value. The returned data slice + * is invalidated whenever the dynptr is invalidated. + * Return + * Pointer to the underlying dynptr data, NULL if the dynptr is + * read-only, if the dynptr is invalid, or if the offset and length + * is out of bounds. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -5443,6 +5454,7 @@ union bpf_attr { FN(ringbuf_discard_dynptr), \ FN(dynptr_read), \ FN(dynptr_write), \ + FN(dynptr_data), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper |