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authorChristoph Hellwig <hch@lst.de>2017-04-25 13:39:54 +0200
committerTejun Heo <tj@kernel.org>2017-04-28 18:08:21 -0400
commitc6ade20f5e50e188d20b711a618b20dd1d50457e (patch)
treea6b882286df26b634acaf06a4a27639287b92fee /drivers
parent1a92e99a55e2689f9c13770fe0068b24476268ef (diff)
libata: reject passthrough WRITE SAME requests
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 Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/ata/libata-scsi.c8
1 files changed, 8 insertions, 0 deletions
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;