[PATCH 5.8 04/16] net: qrtr: fix usage of idr in port assignment to socket

Greg Kroah-Hartman
2020-08-26T12:04:46Z

From: Necip Fazil Yildiran <necip@google.com>

[ Upstream commit 8dfddfb79653df7c38a9c8c4c034f242a36acee9 ]

Passing large uint32 sockaddr_qrtr.port numbers for port allocation
triggers a warning within idr_alloc() since the port number is cast
to int, and thus interpreted as a negative number. This leads to
the rejection of such valid port numbers in qrtr_port_assign() as
idr_alloc() fails.

To avoid the problem, switch to idr_alloc_u32() instead.

Fixes: bdabad3e363d ("net: Add Qualcomm IPC router")
Reported-by: syzbot+f31428628ef672716ea8@syzkaller.appspotmail.com
Signed-off-by: Necip Fazil Yildiran <necip@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/qrtr/qrtr.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -692,23 +692,25 @@ static void qrtr_port_remove(struct qrtr
*/
static int qrtr_port_assign(struct qrtr_sock *ipc, int *port)
{
+ u32 min_port;
int rc;

mutex_lock(&qrtr_port_lock);
if (!*port) {
- rc = idr_alloc(&qrtr_ports, ipc,
- QRTR_MIN_EPH_SOCKET, QRTR_MAX_EPH_SOCKET + 1,
- GFP_ATOMIC);
- if (rc >= 0)
- *port = rc;
+ min_port = QRTR_MIN_EPH_SOCKET;
+ rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, QRTR_MAX_EPH_SOCKET, GFP_ATOMIC);
+ if (!rc)
+ *port = min_port;
} else if (*port < QRTR_MIN_EPH_SOCKET && !capable(CAP_NET_ADMIN)) {
rc = -EACCES;
} else if (*port == QRTR_PORT_CTRL) {
- rc = idr_alloc(&qrtr_ports, ipc, 0, 1, GFP_ATOMIC);
+ min_port = 0;
+ rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, 0, GFP_ATOMIC);
} else {
- rc = idr_alloc(&qrtr_ports, ipc, *port, *port + 1, GFP_ATOMIC);
- if (rc >= 0)
- *port = rc;
+ min_port = *port;
+ rc = idr_alloc_u32(&qrtr_ports, ipc, &min_port, *port, GFP_ATOMIC);
+ if (!rc)
+ *port = min_port;
}
mutex_unlock(&qrtr_port_lock);