6.5-stable review patch. If anyone has any objections, please let me know.
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From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit aa99e5f87bd54db55dd37cb130bd5eb55933027f ]
Andrei Vagin reported bind() regression with strace logs.
If we bind() a TCPv6 socket to ::FFFF:0.0.0.0 and then bind() a TCPv4 socket to 127.0.0.1, the 2nd bind() should fail but now succeeds.
from socket import *
s1 = socket(AF_INET6, SOCK_STREAM) s1.bind(('::ffff:0.0.0.0', 0))
s2 = socket(AF_INET, SOCK_STREAM) s2.bind(('127.0.0.1', s1.getsockname()[1]))
During the 2nd bind(), if tb->family is AF_INET6 and sk->sk_family is AF_INET in inet_bind2_bucket_match_addr_any(), we still need to check if tb has the v4-mapped-v6 wildcard address.
The example above does not work after commit 5456262d2baa ("net: Fix incorrect address comparison when searching for a bind2 bucket"), but the blamed change is not the commit.
Before the commit, the leading zeros of ::FFFF:0.0.0.0 were treated as 0.0.0.0, and the sequence above worked by chance. Technically, this case has been broken since bhash2 was introduced.
Note that if we bind() two sockets to 127.0.0.1 and then ::FFFF:0.0.0.0, the 2nd bind() fails properly because we fall back to using bhash to detect conflicts for the v4-mapped-v6 address.
Fixes: 28044fc1d495 ("net: Add a bhash2 table hashed by port and address") Reported-by: Andrei Vagin avagin@google.com Closes: https://lore.kernel.org/netdev/ZPuYBOFC8zsK6r9T@google.com/ Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/ipv6.h | 5 +++++ net/ipv4/inet_hashtables.c | 3 ++- 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/net/ipv6.h b/include/net/ipv6.h index b08bd694385aa..a14ac821fb36f 100644 --- a/include/net/ipv6.h +++ b/include/net/ipv6.h @@ -784,6 +784,11 @@ static inline bool ipv6_addr_v4mapped(const struct in6_addr *a) cpu_to_be32(0x0000ffff))) == 0UL; }
+static inline bool ipv6_addr_v4mapped_any(const struct in6_addr *a) +{ + return ipv6_addr_v4mapped(a) && ipv4_is_zeronet(a->s6_addr32[3]); +} + static inline bool ipv6_addr_v4mapped_loopback(const struct in6_addr *a) { return ipv6_addr_v4mapped(a) && ipv4_is_loopback(a->s6_addr32[3]); diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 1ab81534f8c55..fb13a28577b01 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -819,7 +819,8 @@ bool inet_bind2_bucket_match_addr_any(const struct inet_bind2_bucket *tb, const #if IS_ENABLED(CONFIG_IPV6) if (sk->sk_family != tb->family) { if (sk->sk_family == AF_INET) - return ipv6_addr_any(&tb->v6_rcv_saddr); + return ipv6_addr_any(&tb->v6_rcv_saddr) || + ipv6_addr_v4mapped_any(&tb->v6_rcv_saddr);
return false; }