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authorJan Kara <jack@suse.cz>2019-06-19 10:05:41 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-03 14:13:38 +0300
commite5fb2093f9e86abe7c742465a8e9908951c463d2 (patch)
treefa3ef7c2a2e424a1767f5570835f500ce09534e7
parentddae0798dd1183183694977c2632e686ed317b06 (diff)
downloadlinux-e5fb2093f9e86abe7c742465a8e9908951c463d2.tar.xz
scsi: vmw_pscsi: Fix use-after-free in pvscsi_queue_lck()
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>
-rw-r--r--drivers/scsi/vmw_pvscsi.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/scsi/vmw_pvscsi.c b/drivers/scsi/vmw_pvscsi.c
index ecee4b3ff073..377b07b2feeb 100644
--- a/drivers/scsi/vmw_pvscsi.c
+++ b/drivers/scsi/vmw_pvscsi.c
@@ -763,6 +763,7 @@ static int pvscsi_queue_lck(struct scsi_cmnd *cmd, void (*done)(struct scsi_cmnd
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_cmnd *cmd, void (*done)(struct scsi_cmnd
}
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;
}