[SRU][B/C/D][PATCH] Bluetooth: hidp: fix buffer overflow

[Connor Kuehl]

From: Young Xiao <YangX92 at hotmail.com>

CVE-2019-11884

Struct ca is copied from userspace. It is not checked whether the "name"
field is NULL terminated, which allows local users to obtain potentially
sensitive information from kernel stack memory, via a HIDPCONNADD command.

This vulnerability is similar to CVE-2011-1079.

Signed-off-by: Young Xiao <YangX92 at hotmail.com>
Signed-off-by: Marcel Holtmann <marcel at holtmann.org>
Cc: stable at vger.kernel.org
(cherry picked from commit a1616a5ac99ede5d605047a9012481ce7ff18b16)
Signed-off-by: Connor Kuehl <connor.kuehl at canonical.com>
---
 net/bluetooth/hidp/sock.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/bluetooth/hidp/sock.c b/net/bluetooth/hidp/sock.c
index 9f85a1943be9..2151913892ce 100644
--- a/net/bluetooth/hidp/sock.c
+++ b/net/bluetooth/hidp/sock.c
@@ -75,6 +75,7 @@ static int do_hidp_sock_ioctl(struct socket *sock, unsigned int cmd, void __user
 			sockfd_put(csock);
 			return err;
 		}
+		ca.name[sizeof(ca.name)-1] = 0;
 
 		err = hidp_connection_add(&ca, csock, isock);
 		if (!err && copy_to_user(argp, &ca, sizeof(ca)))
-- 
2.20.1