diff options
| author |   John Fastabend <john.fastabend@gmail.com> | 2018-12-20 11:35:31 -0800 |
|---|---|---|
| committer |   Daniel Borkmann <daniel@iogearbox.net> | 2018-12-20 23:47:09 +0100 |
| commit | 7a69c0f250568e6ab72f401b2c69aa0e666c94f2 (patch) | |
| tree | 8f3fb3338a0cb3d296dc33f49d821b64e8ae12be | |
| parent | bpf: sk_msg, improve offset chk in _is_valid_access (diff) | |
| download | linux-dev-7a69c0f250568e6ab72f401b2c69aa0e666c94f2.tar.xz linux-dev-7a69c0f250568e6ab72f401b2c69aa0e666c94f2.zip | |
bpf: skmsg, replace comments with BUILD bug
Enforce comment on structure layout dependency with a BUILD_BUG_ON
to ensure the condition is maintained.
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | include/linux/skmsg.h | 4 | ||||
| -rw-r--r-- | net/core/filter.c | 3 |
2 files changed, 4 insertions, 3 deletions
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h index eb8f6cb84c10..dd57e6f408b1 100644 --- a/include/linux/skmsg.h +++ b/include/linux/skmsg.h @@ -36,9 +36,7 @@ struct sk_msg_sg { struct scatterlist data[MAX_MSG_FRAGS + 1]; }; -/* UAPI in filter.c depends on struct sk_msg_sg being first element. If - * this is moved filter.c also must be updated. - */ +/* UAPI in filter.c depends on struct sk_msg_sg being first element. */ struct sk_msg { struct sk_msg_sg sg; void *data; diff --git a/net/core/filter.c b/net/core/filter.c index 6bd9f08f6162..447dd1bad31f 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -7425,6 +7425,9 @@ static u32 sk_msg_convert_ctx_access(enum bpf_access_type type, int off; #endif + /* convert ctx uses the fact sg element is first in struct */ + BUILD_BUG_ON(offsetof(struct sk_msg, sg) != 0); + switch (si->off) { case offsetof(struct sk_msg_md, data): *insn++ = BPF_LDX_MEM(BPF_FIELD_SIZEOF(struct sk_msg, data), |