Re: [PATCH net-next] net: Fix incorrect address comparison when searching for a bind2 bucket
From: Andrei Vagin <hidden>
Date: 2023-09-08 21:54:17
On Mon, Sep 26, 2022 at 05:25:44PM -0700, Martin KaFai Lau wrote:
From: Martin KaFai Lau <martin.lau@kernel.org> The v6_rcv_saddr and rcv_saddr are inside a union in the 'struct inet_bind2_bucket'. When searching a bucket by following the bhash2 hashtable chain, eg. inet_bind2_bucket_match, it is only using the sk->sk_family and there is no way to check if the inet_bind2_bucket has a v6 or v4 address in the union. This leads to an uninit-value KMSAN report in [0] and also potentially incorrect matches. This patch fixes it by adding a family member to the inet_bind2_bucket and then tests 'sk->sk_family != tb->family' before matching the sk's address to the tb's address.
It seems this patch doesn't handle v4mapped addresses properly. One of
gVisor test started failing with this change:
socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
bind(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::ffff:0.0.0.0", &sin6_addr), sin6_scope_id=0}, 28) = 0
getsockname(3, {sa_family=AF_INET6, sin6_port=htons(33789), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::ffff:0.0.0.0", &sin6_addr), sin6_scope_id=0}, [28]) = 0
socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 4
bind(4, {sa_family=AF_INET6, sin6_port=htons(33789), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_scope_id=0}, 28) = 0
socket(AF_INET, SOCK_STREAM, IPPROTO_IP) = 5
bind(5, {sa_family=AF_INET, sin_port=htons(33789), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
The test expects that the second bind returns EADDRINUSE.
Thanks,
Andrei
quoted hunk ↗ jump to hunk
Cc: Joanne Koong <joannelkoong@gmail.com> Cc: Alexander Potapenko <glider@google.com> Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address") Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> --- include/net/inet_hashtables.h | 3 +++ net/ipv4/inet_hashtables.c | 10 ++++++++++ 2 files changed, 13 insertions(+)diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h index 9121ccab1fa1..3af1e927247d 100644 --- a/include/net/inet_hashtables.h +++ b/include/net/inet_hashtables.h@@ -95,6 +95,9 @@ struct inet_bind2_bucket { possible_net_t ib_net; int l3mdev; unsigned short port; +#if IS_ENABLED(CONFIG_IPV6) + unsigned short family; +#endif union { #if IS_ENABLED(CONFIG_IPV6) struct in6_addr v6_rcv_saddr;diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 74e64aad5114..49db8c597eea 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c@@ -109,6 +109,7 @@ static void inet_bind2_bucket_init(struct inet_bind2_bucket *tb, tb->l3mdev = l3mdev; tb->port = port; #if IS_ENABLED(CONFIG_IPV6) + tb->family = sk->sk_family; if (sk->sk_family == AF_INET6) tb->v6_rcv_saddr = sk->sk_v6_rcv_saddr; else@@ -146,6 +147,9 @@ static bool inet_bind2_bucket_addr_match(const struct inet_bind2_bucket *tb2, const struct sock *sk) { #if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family != tb2->family) + return false; + if (sk->sk_family == AF_INET6) return ipv6_addr_equal(&tb2->v6_rcv_saddr, &sk->sk_v6_rcv_saddr);@@ -791,6 +795,9 @@ static bool inet_bind2_bucket_match(const struct inet_bind2_bucket *tb, int l3mdev, const struct sock *sk) { #if IS_ENABLED(CONFIG_IPV6) + if (sk->sk_family != tb->family) + return false; + if (sk->sk_family == AF_INET6) return net_eq(ib2_net(tb), net) && tb->port == port && tb->l3mdev == l3mdev &&@@ -807,6 +814,9 @@ bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb, const #if IS_ENABLED(CONFIG_IPV6) struct in6_addr addr_any = {}; + if (sk->sk_family != tb->family) + return false; + if (sk->sk_family == AF_INET6) return net_eq(ib2_net(tb), net) && tb->port == port && tb->l3mdev == l3mdev &&-- 2.30.2