From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B8E922F24 for ; Wed, 12 Apr 2023 08:48:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C34DC433EF; Wed, 12 Apr 2023 08:48:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681289308; bh=I44o5K3/fVFmDAqmxZRhB37N9DMHiXe/wyi0gEi+8v0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Fnw7vppEgeLIHn1L6QhvcH5kBGW5hGmjZBNrj0i/Tmq1Z51y+tWZ4xf9dY3WuFv6x EBFdqmPBQyLD2P2yRE44cBIyKsWaYBXujDm+EghMKvlsXNb+ngBhPHvnG8XOi3HFBU vpBa8i9y7ru2hk8xuXsWDGGjAJm3psXPAua1EJW8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuniyuki Iwashima , Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.2 049/173] ping: Fix potentail NULL deref for /proc/net/icmp. Date: Wed, 12 Apr 2023 10:32:55 +0200 Message-Id: <20230412082840.097638160@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230412082838.125271466@linuxfoundation.org> References: <20230412082838.125271466@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Kuniyuki Iwashima [ Upstream commit ab5fb73ffa01072b4d8031cc05801fa1cb653bee ] After commit dbca1596bbb0 ("ping: convert to RCU lookups, get rid of rwlock"), we use RCU for ping sockets, but we should use spinlock for /proc/net/icmp to avoid a potential NULL deref mentioned in the previous patch. Let's go back to using spinlock there. Note we can convert ping sockets to use hlist instead of hlist_nulls because we do not use SLAB_TYPESAFE_BY_RCU for ping sockets. Fixes: dbca1596bbb0 ("ping: convert to RCU lookups, get rid of rwlock") Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/ping.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c index 409ec2a1f95b0..5178a3f3cb537 100644 --- a/net/ipv4/ping.c +++ b/net/ipv4/ping.c @@ -1089,13 +1089,13 @@ static struct sock *ping_get_idx(struct seq_file *seq, loff_t pos) } void *ping_seq_start(struct seq_file *seq, loff_t *pos, sa_family_t family) - __acquires(RCU) + __acquires(ping_table.lock) { struct ping_iter_state *state = seq->private; state->bucket = 0; state->family = family; - rcu_read_lock(); + spin_lock(&ping_table.lock); return *pos ? ping_get_idx(seq, *pos-1) : SEQ_START_TOKEN; } @@ -1121,9 +1121,9 @@ void *ping_seq_next(struct seq_file *seq, void *v, loff_t *pos) EXPORT_SYMBOL_GPL(ping_seq_next); void ping_seq_stop(struct seq_file *seq, void *v) - __releases(RCU) + __releases(ping_table.lock) { - rcu_read_unlock(); + spin_unlock(&ping_table.lock); } EXPORT_SYMBOL_GPL(ping_seq_stop); -- 2.39.2