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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        syzbot <syzbot+0049bebbf3042dbd2e8f@syzkaller.appspotmail.com>,
        syzbot <syzbot+915c9f99f3dbc4bd6cd1@syzkaller.appspotmail.com>,
        Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
        Santosh Shilimkar <santosh.shilimkar@oracle.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.0 62/89] net/rds: Check address length before reading address family
Date:   Tue, 30 Apr 2019 13:38:53 +0200
Message-Id: <20190430113612.606541047@linuxfoundation.org>
In-Reply-To: <20190430113609.741196396@linuxfoundation.org>
References: <20190430113609.741196396@linuxfoundation.org>
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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

commit dd3ac9a684358b8c1d5c432ca8322aaf5e4f28ee upstream.

syzbot is reporting uninitialized value at rds_connect() [1] and
rds_bind() [2]. This is because syzbot is passing ulen == 0 whereas
these functions expect that it is safe to access sockaddr->family field
in order to determine minimal address length for validation.

[1] https://syzkaller.appspot.com/bug?id=f4e61c010416c1e6f0fa3ffe247561b60a50ad71
[2] https://syzkaller.appspot.com/bug?id=a4bf9e41b7e055c3823fdcd83e8c58ca7270e38f

Reported-by: syzbot <syzbot+0049bebbf3042dbd2e8f@syzkaller.appspotmail.com>
Reported-by: syzbot <syzbot+915c9f99f3dbc4bd6cd1@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/rds/af_rds.c |    3 +++
 net/rds/bind.c   |    2 ++
 2 files changed, 5 insertions(+)

--- a/net/rds/af_rds.c
+++ b/net/rds/af_rds.c
@@ -506,6 +506,9 @@ static int rds_connect(struct socket *so
 	struct rds_sock *rs = rds_sk_to_rs(sk);
 	int ret = 0;
 
+	if (addr_len < offsetofend(struct sockaddr, sa_family))
+		return -EINVAL;
+
 	lock_sock(sk);
 
 	switch (uaddr->sa_family) {
--- a/net/rds/bind.c
+++ b/net/rds/bind.c
@@ -173,6 +173,8 @@ int rds_bind(struct socket *sock, struct
 	/* We allow an RDS socket to be bound to either IPv4 or IPv6
 	 * address.
 	 */
+	if (addr_len < offsetofend(struct sockaddr, sa_family))
+		return -EINVAL;
 	if (uaddr->sa_family == AF_INET) {
 		struct sockaddr_in *sin = (struct sockaddr_in *)uaddr;