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[SCSI] don't reference freed command in scsi_init_sgtable

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commit 0479633686
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: 0479633686
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Christoph Hellwig 2014-04-15 12:24:55 +02:00 committed by James Bottomley
parent 67c99a72e3
commit 5e012aad85
1 changed files with 2 additions and 1 deletions
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3
drivers/scsi/scsi_lib.c
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@ -1044,6 +1044,7 @@ static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
*/
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 @@ err_exit:
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);