| Message ID | 20170425113954.23121-1-hch@lst.de |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
Christoph, > The WRITE SAME to TRIM translation rewrites the DATA OUT buffer. While > the SCSI code accomodates for this by passing a read-writable buffer > userspace applications don't cater for this behavior. In fact it can > be used to rewrite e.g. a readonly file through mmap and should be > considered as a security fix. Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
On Tue, Apr 25, 2017 at 01:39:54PM +0200, Christoph Hellwig wrote: > The WRITE SAME to TRIM translation rewrites the DATA OUT buffer. While > the SCSI code accomodates for this by passing a read-writable buffer > userspace applications don't cater for this behavior. In fact it can > be used to rewrite e.g. a readonly file through mmap and should be > considered as a security fix. > > Signed-off-by: Christoph Hellwig <hch@lst.de> > Cc: stable@vger.kernel.org Applied to libata/for-4.12, assuming we aren't doing rc9. Thanks.
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 1ac70744ae7b..50f56d066936 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -3462,6 +3462,14 @@ static unsigned int ata_scsi_write_same_xlat(struct ata_queued_cmd *qc) if (unlikely(!dev->dma_mode)) goto invalid_opcode; + /* + * We only allow sending this command through the block layer, + * as it modifies the DATA OUT buffer, which would corrupt user + * memory for SG_IO commands. + */ + if (unlikely(blk_rq_is_passthrough(scmd->request))) + goto invalid_opcode; + if (unlikely(scmd->cmd_len < 16)) { fp = 15; goto invalid_fld;
The WRITE SAME to TRIM translation rewrites the DATA OUT buffer. While the SCSI code accomodates for this by passing a read-writable buffer userspace applications don't cater for this behavior. In fact it can be used to rewrite e.g. a readonly file through mmap and should be considered as a security fix. Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: stable@vger.kernel.org --- drivers/ata/libata-scsi.c | 8 ++++++++ 1 file changed, 8 insertions(+)