Re: [PATCH v2 net-next] bluetooth: unregister correct BTPROTO for CMTP

From: Chenyuan Mi
Date: Mon Apr 03 2023 - 21:53:12 EST


On error unregister BTPROTO_CMTP to match the registration earlier in
the same code-path. Without this change BTPROTO_HIDP is incorrectly
unregistered.

This bug does not appear to cause serious security problem.

The function 'bt_sock_unregister' takes its parameter as an index and
NULLs the corresponding element of 'bt_proto' which is an array of
pointers. When 'bt_proto' dereferences each element, it would check
whether the element is empty or not. Therefore, the problem of null
pointer deference does not occur.

Found by inspection.

Fixes: 8c8de589cedd ("Bluetooth: Added /proc/net/cmtp via bt_procfs_init()")
Signed-off-by: Chenyuan Mi <michenyuan@xxxxxxxxxx>
---
net/bluetooth/cmtp/sock.c | 2 +-
1 files changed, 1 insertions(+), 1 deletion(-)

diff --git a/net/bluetooth/cmtp/sock.c b/net/bluetooth/cmtp/sock.c
index 96d49d9fae96..cf4370055ce2 100644
--- a/net/bluetooth/cmtp/sock.c
+++ b/net/bluetooth/cmtp/sock.c
@@ -250,7 +250,7 @@ int cmtp_init_sockets(void)
err = bt_procfs_init(&init_net, "cmtp", &cmtp_sk_list, NULL);
if (err < 0) {
BT_ERR("Failed to create CMTP proc file");
- bt_sock_unregister(BTPROTO_HIDP);
+ bt_sock_unregister(BTPROTO_CMTP);
goto error;
}

--
2.25.1