From: Christoph Hellwig <hch@lst.de>
Date: Tue, 25 Apr 2017 11:39:54 +0000 (+0200)
Subject: libata: reject passthrough WRITE SAME requests
X-Git-Tag: v3.2.92~16
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4d34a500e77add127cdee5b4778079596a9ebabe;p=pandora-kernel.git

libata: reject passthrough WRITE SAME requests

commit c6ade20f5e50e188d20b711a618b20dd1d50457e upstream.

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>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
[bwh: Backported to 3.2:
 - Open-code blk_rq_is_passthrough()
 - We don't distinguish which field is invaid so goto invalid_fld
 - Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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