+ lib-scatterlist-error-handling-in-__sg_alloc_table.patch added to -mm tree

+ lib-scatterlist-error-handling-in-__sg_alloc_table.patch added to -mm tree

[akpm]

Subject: + lib-scatterlist-error-handling-in-__sg_alloc_table.patch added to -mm tree
To: dan.carpenter@oracle.com,akinobu.mita@gmail.com,daniel.vetter@ffwll.ch,imre.deak@intel.com,maximlevitsky@gmail.com,tj@kernel.org
From: akpm@linux-foundation.org
Date: Wed, 26 Jun 2013 14:33:01 -0700


The patch titled
     Subject: lib/scatterlist: error handling in __sg_alloc_table()
has been added to the -mm tree.  Its filename is
     lib-scatterlist-error-handling-in-__sg_alloc_table.patch

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------------------------------------------------------
From: Dan Carpenter <dan.carpenter@oracle.com>
Subject: lib/scatterlist: error handling in __sg_alloc_table()

I was reviewing code which I suspected might allocate a zero size SG
table.  That will cause memory corruption.  Also we can't return before
doing the memset or we could end up using uninitialized memory in the
cleanup path.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/scatterlist.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff -puN lib/scatterlist.c~lib-scatterlist-error-handling-in-__sg_alloc_table lib/scatterlist.c
--- a/lib/scatterlist.c~lib-scatterlist-error-handling-in-__sg_alloc_table
+++ a/lib/scatterlist.c
@@ -247,13 +247,15 @@ int __sg_alloc_table(struct sg_table *ta
 	struct scatterlist *sg, *prv;
 	unsigned int left;
 
+	memset(table, 0, sizeof(*table));
+
+	if (nents == 0)
+		return -EINVAL;
 #ifndef ARCH_HAS_SG_CHAIN
 	if (WARN_ON_ONCE(nents > max_ents))
 		return -EINVAL;
 #endif
 
-	memset(table, 0, sizeof(*table));