From 5e012aad85f2ee31d7de5c21d63ccd2702d63db2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 15 Apr 2014 12:24:55 +0200 Subject: [PATCH] [SCSI] don't reference freed command in scsi_init_sgtable Patch commit 0479633686d370303e3430256ace4bd5f7f138dc Author: Christoph Hellwig 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 Signed-off-by: Christoph Hellwig Signed-off-by: James Bottomley --- drivers/scsi/scsi_lib.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 65a123d9c676..54eff6a79fb8 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -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); -- 2.20.1