| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.1 20/55] scsi: vmw_pscsi: Fix use-after-free in pvscsi_queue_lck() | Date | Tue, 2 Jul 2019 10:01:28 +0200 |
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From: Jan Kara <jack@suse.cz>
commit 240b4cc8fd5db138b675297d4226ec46594d9b3b upstream.
Once we unlock adapter->hw_lock in pvscsi_queue_lck() nothing prevents just queued scsi_cmnd from completing and freeing the request. Thus cmd->cmnd[0] dereference can dereference already freed request leading to kernel crashes or other issues (which one of our customers observed). Store cmd->cmnd[0] in a local variable before unlocking adapter->hw_lock to fix the issue.
CC: <stable@vger.kernel.org> Signed-off-by: Jan Kara <jack@suse.cz> Reviewed-by: Ewan D. Milne <emilne@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/scsi/vmw_pvscsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/scsi/vmw_pvscsi.c +++ b/drivers/scsi/vmw_pvscsi.c @@ -763,6 +763,7 @@ static int pvscsi_queue_lck(struct scsi_ struct pvscsi_adapter *adapter = shost_priv(host); struct pvscsi_ctx *ctx; unsigned long flags; + unsigned char op; spin_lock_irqsave(&adapter->hw_lock, flags); @@ -775,13 +776,14 @@ static int pvscsi_queue_lck(struct scsi_ } cmd->scsi_done = done; + op = cmd->cmnd[0]; dev_dbg(&cmd->device->sdev_gendev, - "queued cmd %p, ctx %p, op=%x\n", cmd, ctx, cmd->cmnd[0]); + "queued cmd %p, ctx %p, op=%x\n", cmd, ctx, op); spin_unlock_irqrestore(&adapter->hw_lock, flags); - pvscsi_kick_io(adapter, cmd->cmnd[0]); + pvscsi_kick_io(adapter, op); return 0; }
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