6.4-stable review patch. If anyone has any objections, please let me know.
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From: Lorenz Bauer lmb@isovalent.com
[ Upstream commit 8897562f67b3e61ad736cd5c9f307447d33280e4 ]
Kumar reported a KASAN splat in tcp_v6_rcv:
bash-5.2# ./test_progs -t btf_skc_cls_ingress ... [ 51.810085] BUG: KASAN: slab-out-of-bounds in tcp_v6_rcv+0x2d7d/0x3440 [ 51.810458] Read of size 2 at addr ffff8881053f038c by task test_progs/226
The problem is that inet[6]_steal_sock accesses sk->sk_protocol without accounting for request or timewait sockets. To fix this we can't just check sock_common->skc_reuseport since that flag is present on timewait sockets.
Instead, add a fullsock check to avoid the out of bands access of sk_protocol.
Fixes: 9c02bec95954 ("bpf, net: Support SO_REUSEPORT sockets with bpf_sk_assign") Reported-by: Kumar Kartikeya Dwivedi memxor@gmail.com Signed-off-by: Lorenz Bauer lmb@isovalent.com Link: https://lore.kernel.org/r/20230815-bpf-next-v2-1-95126eaa4c1b@isovalent.com Signed-off-by: Martin KaFai Lau martin.lau@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/inet6_hashtables.h | 2 +- include/net/inet_hashtables.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/net/inet6_hashtables.h b/include/net/inet6_hashtables.h index 475e672b4facc..12780b8fb5630 100644 --- a/include/net/inet6_hashtables.h +++ b/include/net/inet6_hashtables.h @@ -107,7 +107,7 @@ struct sock *inet6_steal_sock(struct net *net, struct sk_buff *skb, int doff, if (!sk) return NULL;
- if (!prefetched) + if (!prefetched || !sk_fullsock(sk)) return sk;
if (sk->sk_protocol == IPPROTO_TCP) { diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h index a1b8eb147ce73..9414cb4e6e624 100644 --- a/include/net/inet_hashtables.h +++ b/include/net/inet_hashtables.h @@ -455,7 +455,7 @@ struct sock *inet_steal_sock(struct net *net, struct sk_buff *skb, int doff, if (!sk) return NULL;
- if (!prefetched) + if (!prefetched || !sk_fullsock(sk)) return sk;
if (sk->sk_protocol == IPPROTO_TCP) {