net: Fix incorrect address comparison when searching for a bind2 bucket

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.

Cc: Joanne Koong <joannelkoong@gmail.com>
Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Tested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/r/20220927002544.3381205-1-kafai@fb.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/include/net/inet_hashtables.h b/include/net/inet_hashtables.h
index 9121cca..3af1e92 100644 (file)
--- 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 74e64aa..49db8c5 100644 (file)
--- 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 &&