scsi: scsi_debug: Fix possible UAF in sdebug_add_host_helper()

[ Upstream commit e208a1d795a08d1ac0398c79ad9c58106531bcc5 ]

If device_register() fails in sdebug_add_host_helper(), it will goto clean
and sdbg_host will be freed, but sdbg_host->host_list will not be removed
from sdebug_host_list, then list traversal may cause UAF. Fix it.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Yuan Can <yuancan@huawei.com>
Link: https://lore.kernel.org/r/20221117084421.58918-1-yuancan@huawei.com
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 747e1cb..2b5e249 100644 (file)
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -7132,8 +7132,12 @@ static int sdebug_add_host_helper(int per_host_idx)
        dev_set_name(&sdbg_host->dev, "adapter%d", sdebug_num_hosts);
 
        error = device_register(&sdbg_host->dev);
-       if (error)
+       if (error) {
+               spin_lock(&sdebug_host_list_lock);
+               list_del(&sdbg_host->host_list);
+               spin_unlock(&sdebug_host_list_lock);
                goto clean;
+       }
 
        ++sdebug_num_hosts;
        return 0;