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Date: Tue, 21 May 2019 08:52:38 +0100 From: Lorenz Bauer <lmb@...udflare.com> To: netdev@...r.kernel.org, bpf@...r.kernel.org, ast@...nel.org, daniel@...earbox.com Cc: joe@...valent.com, Lorenz Bauer <lmb@...udflare.com> Subject: [PATCH bpf] bpf: fix out-of-bounds read in __bpf_skc_lookup __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 <lmb@...udflare.com> --- 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 55bfc941d17a..76f1d99640e2 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -5304,7 +5304,13 @@ __bpf_skc_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; -- 2.19.1
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