From 4faf940dd869c36436ff6f0a0b20369fdf5da68b Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 24 Jan 2017 01:06:26 +0100 Subject: [PATCH] bpf: simplify __is_valid_access test on cb 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 Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- 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 90383860e224..883975fa4ed1 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: -- 2.30.2