From: Xiaomeng Tong Date: Wed, 6 Apr 2022 19:04:44 +0000 (+0200) Subject: drbd: fix an invalid memory access caused by incorrect use of list iterator X-Git-Tag: v5.16.20~46 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b1fe4eb2e9c14b8a0bda2f06c373049880514380;p=thirdparty%2Fkernel%2Fstable.git drbd: fix an invalid memory access caused by incorrect use of list iterator 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 Reviewed-by: Christoph Böhmwalder Reviewed-by: Lars Ellenberg Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 53ba2dddba6e6..b1676c6329962 100644 --- 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(struct drbd_config_context *adm_ctx, unsig 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(struct drbd_config_context *adm_ctx, unsig 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);