[PATCH AUTOSEL 5.1 08/95] bpf: fix out-of-bounds read in __bpf_skc_lookup
From: Sasha Levin <sashal@kernel.org>
Date: 2019-06-27 00:30:53
Also in:
bpf, lkml, stable
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [networking] (tcx & tc bpf, sock_addr), networking [general], the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Lorenz Bauer <redacted>
[ Upstream commit 9b28ae243ef3b13d8a88b5451d025475c75ebdef ]
__bpf_skc_lookup takes a socket tuple and the length of the
tuple as an argument. Based on the length, it decides which
address family to pass to the helper function sk_lookup.
In case of AF_INET6, it fails to verify that the length
of the tuple is long enough. sk_lookup may therefore access
data past the end of the tuple.
Fixes: 6acc9b432e67 ("bpf: Add helper to retrieve socket in BPF")
Signed-off-by: Lorenz Bauer <redacted>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/filter.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/net/core/filter.c b/net/core/filter.c
index 27e61ffd9039..85f9e960588b 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c@@ -5173,7 +5173,13 @@ __bpf_sk_lookup(struct sk_buff *skb, struct bpf_sock_tuple *tuple, u32 len, struct net *net; int sdif; - family = len == sizeof(tuple->ipv4) ? AF_INET : AF_INET6; + if (len == sizeof(tuple->ipv4)) + family = AF_INET; + else if (len == sizeof(tuple->ipv6)) + family = AF_INET6; + else + return NULL; + if (unlikely(family == AF_UNSPEC || flags || !((s32)netns_id < 0 || netns_id <= S32_MAX))) goto out;
--
2.20.1