The __is_valid_access() test for cb[] from 62c7989b24db ("bpf: allow
b/h/w/dw access for bpf's cb in ctx") was done unnecessarily complex,
we can just simplify it the same way as recent fix from 2d071c643f1c
("bpf, trace: make ctx access checks more robust") did. Overflow can
never happen as size is 1/2/4/8 depending on access.
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Acked-by: Alexei Starovoitov <a...@kernel.org>
---
net/core/filter.c | 15 ++-------------
1 file changed, 2 insertions(+), 13 deletions(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 9038386..883975f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2784,19 +2784,8 @@ static bool __is_valid_access(int off, int size)
switch (off) {
case offsetof(struct __sk_buff, cb[0]) ...
offsetof(struct __sk_buff, cb[4]) + sizeof(__u32) - 1:
- if (size == sizeof(__u16) &&
- off > offsetof(struct __sk_buff, cb[4]) + sizeof(__u16))
- return false;
- if (size == sizeof(__u32) &&
- off > offsetof(struct __sk_buff, cb[4]))
- return false;
- if (size == sizeof(__u64) &&
- off > offsetof(struct __sk_buff, cb[2]))
- return false;
- if (size != sizeof(__u8) &&
- size != sizeof(__u16) &&
- size != sizeof(__u32) &&
- size != sizeof(__u64))
+ if (off + size >
+ offsetof(struct __sk_buff, cb[4]) + sizeof(__u32))
return false;
break;
default:
--
1.9.3
