From: Andrei Vagin <avagin@gmail•com>
To: Martin KaFai Lau <kafai@fb•com>
Cc: netdev@vger•kernel.org, David Miller <davem@davemloft•net>,
Eric Dumazet <edumazet@google•com>,
Jakub Kicinski <kuba@kernel•org>,
kernel-team@fb•com, Paolo Abeni <pabeni@redhat•com>,
Joanne Koong <joannelkoong@gmail•com>,
Alexander Potapenko <glider@google•com>,
Martin KaFai Lau <martin.lau@kernel•org>
Subject: Re: [PATCH net-next] net: Fix incorrect address comparison when searching for a bind2 bucket
Date: Fri, 8 Sep 2023 14:54:12 -0700 [thread overview]
Message-ID: <ZPuYBOFC8zsK6r9T@google.com> (raw)
In-Reply-To: <20220927002544.3381205-1-kafai@fb.com>
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
>
> 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
>
next prev parent reply other threads:[~2023-09-08 21:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-27 0:25 [PATCH net-next] net: Fix incorrect address comparison when searching for a bind2 bucket Martin KaFai Lau
2022-09-28 3:49 ` Eric Dumazet
2022-09-28 4:46 ` Martin KaFai Lau
2022-09-28 5:07 ` Eric Dumazet
2022-09-28 11:15 ` Alexander Potapenko
2022-09-29 2:20 ` patchwork-bot+netdevbpf
2023-09-08 21:54 ` Andrei Vagin [this message]
2023-09-09 7:05 ` Kuniyuki Iwashima
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