| Message ID | 20190619070541.30070-1-jack@suse.cz (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 240b4cc8fd5db138b675297d4226ec46594d9b3b |
| Headers | show |
| Series | scsi: vmw_pscsi: Fix use-after-free in pvscsi_queue_lck() | expand |
On Wed, 2019-06-19 at 09:05 +0200, Jan Kara wrote: > 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> > --- > drivers/scsi/vmw_pvscsi.c | 6 ++++-- > 1 file 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; > } Reviewed-by: Ewan D. Milne <emilne@redhat.com>
Jan, > 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. Applied to 5.2/scsi-fixes. Thanks!
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; }
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> --- drivers/scsi/vmw_pvscsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)