[SCSI] don't reference freed command in scsi_init_sgtable
Patch
commit 0479633686d370303e3430256ace4bd5f7f138dc
Author: Christoph Hellwig <hch@infradead.org>
Date: Thu Feb 20 14:20:55 2014 -0800
[SCSI] do not manipulate device reference counts in scsi_get/put_command
Introduced a use after free: when scsi_init_io fails we have to release our
device reference, but we do this trying to reference the just freed command.
Add a local scsi_device pointer to fix this.
Fixes: 0479633686d370303e3430256ace4bd5f7f138dc
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 65a123d..54eff6a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1044,6 +1044,7 @@
*/
int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
{
+ struct scsi_device *sdev = cmd->device;
struct request *rq = cmd->request;
int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask);
@@ -1091,7 +1092,7 @@
scsi_release_buffers(cmd);
cmd->request->special = NULL;
scsi_put_command(cmd);
- put_device(&cmd->device->sdev_gendev);
+ put_device(&sdev->sdev_gendev);
return error;
}
EXPORT_SYMBOL(scsi_init_io);