[PATCH 235/379][SRU][OEM-5.6] net: qrtr: fix usage of idr in port assignment to socket

[You-Sheng Yang]

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

BugLink: https://bugs.launchpad.net/bugs/1879633

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 at syzkaller.appspotmail.com
Signed-off-by: Necip Fazil Yildiran <necip at google.com>
Reviewed-by: Dmitry Vyukov <dvyukov at google.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
(cherry picked from commit 8dfddfb79653df7c38a9c8c4c034f242a36acee9)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 net/qrtr/qrtr.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 300a104b9a0f..85ab4559f057 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -692,23 +692,25 @@ static void qrtr_port_remove(struct qrtr_sock *ipc)
  */
 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);
 
-- 
2.29.2