| From ae4d37b5df749926891583d42a6801b5da11e3c1 Mon Sep 17 00:00:00 2001 |
| From: Xiaomeng Tong <xiam0nd.tong@gmail.com> |
| Date: Wed, 6 Apr 2022 21:04:44 +0200 |
| Subject: drbd: fix an invalid memory access caused by incorrect use of list iterator |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
| Content-Transfer-Encoding: 8bit |
| |
| From: Xiaomeng Tong <xiam0nd.tong@gmail.com> |
| |
| commit ae4d37b5df749926891583d42a6801b5da11e3c1 upstream. |
| |
| The bug is here: |
| idr_remove(&connection->peer_devices, vnr); |
| |
| If the previous for_each_connection() don't exit early (no goto hit |
| inside the loop), the iterator 'connection' after the loop will be a |
| bogus pointer to an invalid structure object containing the HEAD |
| (&resource->connections). As a result, the use of 'connection' above |
| will lead to a invalid memory access (including a possible invalid free |
| as idr_remove could call free_layer). |
| |
| The original intention should have been to remove all peer_devices, |
| but the following lines have already done the work. So just remove |
| this line and the unneeded label, to fix this bug. |
| |
| Cc: stable@vger.kernel.org |
| Fixes: c06ece6ba6f1b ("drbd: Turn connection->volumes into connection->peer_devices") |
| Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com> |
| Reviewed-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> |
| Reviewed-by: Lars Ellenberg <lars.ellenberg@linbit.com> |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/block/drbd/drbd_main.c | 6 ++---- |
| 1 file changed, 2 insertions(+), 4 deletions(-) |
| |
| --- a/drivers/block/drbd/drbd_main.c |
| +++ b/drivers/block/drbd/drbd_main.c |
| @@ -2791,12 +2791,12 @@ enum drbd_ret_code drbd_create_device(st |
| |
| if (init_submitter(device)) { |
| err = ERR_NOMEM; |
| - goto out_idr_remove_vol; |
| + goto out_idr_remove_from_resource; |
| } |
| |
| err = add_disk(disk); |
| if (err) |
| - goto out_idr_remove_vol; |
| + goto out_idr_remove_from_resource; |
| |
| /* inherit the connection state */ |
| device->state.conn = first_connection(resource)->cstate; |
| @@ -2810,8 +2810,6 @@ enum drbd_ret_code drbd_create_device(st |
| drbd_debugfs_device_add(device); |
| return NO_ERROR; |
| |
| -out_idr_remove_vol: |
| - idr_remove(&connection->peer_devices, vnr); |
| out_idr_remove_from_resource: |
| for_each_connection(connection, resource) { |
| peer_device = idr_remove(&connection->peer_devices, vnr); |
