diff options
| author | Phil Sutter <phil@nwl.cc> | 2023-12-05 21:58:12 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-12-13 18:18:12 +0100 |
| commit | 69431f609bf37311fbf90c507f8540f9ddf667c1 (patch) | |
| tree | 0c7326bcc5ac33e4e89df739cc26f818aff2397a | |
| parent | c61c61d7e7de951d585db4809544f3cc876ef4a7 (diff) | |
netfilter: xt_owner: Fix for unsafe access of sk->sk_socket
[ Upstream commit 7ae836a3d630e146b732fe8ef7d86b243748751f ]
A concurrently running sock_orphan() may NULL the sk_socket pointer in
between check and deref. Follow other users (like nft_meta.c for
instance) and acquire sk_callback_lock before dereferencing sk_socket.
Fixes: 0265ab44bacc ("[NETFILTER]: merge ipt_owner/ip6t_owner in xt_owner")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | net/netfilter/xt_owner.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/net/netfilter/xt_owner.c b/net/netfilter/xt_owner.c index e85ce69924ae..50332888c8d2 100644 --- a/net/netfilter/xt_owner.c +++ b/net/netfilter/xt_owner.c @@ -76,18 +76,23 @@ owner_mt(const struct sk_buff *skb, struct xt_action_param *par) */ return false; - filp = sk->sk_socket->file; - if (filp == NULL) + read_lock_bh(&sk->sk_callback_lock); + filp = sk->sk_socket ? sk->sk_socket->file : NULL; + if (filp == NULL) { + read_unlock_bh(&sk->sk_callback_lock); return ((info->match ^ info->invert) & (XT_OWNER_UID | XT_OWNER_GID)) == 0; + } if (info->match & XT_OWNER_UID) { kuid_t uid_min = make_kuid(net->user_ns, info->uid_min); kuid_t uid_max = make_kuid(net->user_ns, info->uid_max); if ((uid_gte(filp->f_cred->fsuid, uid_min) && uid_lte(filp->f_cred->fsuid, uid_max)) ^ - !(info->invert & XT_OWNER_UID)) + !(info->invert & XT_OWNER_UID)) { + read_unlock_bh(&sk->sk_callback_lock); return false; + } } if (info->match & XT_OWNER_GID) { @@ -112,10 +117,13 @@ owner_mt(const struct sk_buff *skb, struct xt_action_param *par) } } - if (match ^ !(info->invert & XT_OWNER_GID)) + if (match ^ !(info->invert & XT_OWNER_GID)) { + read_unlock_bh(&sk->sk_callback_lock); return false; + } } + read_unlock_bh(&sk->sk_callback_lock); return true; } |