+ mm-mempolicy-require-at-least-one-nodeid-for-mpol_preferred.patch added to -mm tree

+ mm-mempolicy-require-at-least-one-nodeid-for-mpol_preferred.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: mempolicy: require at least one nodeid for MPOL_PREFERRED
has been added to the -mm tree.  Its filename is
     mm-mempolicy-require-at-least-one-nodeid-for-mpol_preferred.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-mempolicy-require-at-least-one-nodeid-for-mpol_preferred.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-mempolicy-require-at-least-one-nodeid-for-mpol_preferred.patch

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------------------------------------------------------
From: Randy Dunlap <rdunlap@infradead.org>
Subject: mm: mempolicy: require at least one nodeid for MPOL_PREFERRED

Using an empty (malformed) nodelist that is not caught during mount option
parsing leads to a stack-out-of-bounds access.

The option string that was used was: "mpol=prefer:,".  However,
MPOL_PREFERRED requires a single node number, which is not being provided
here.

Add a check that 'nodes' is not empty after parsing for MPOL_PREFERRED's
nodeid.

Link: http://lkml.kernel.org/r/89526377-7eb6-b662-e1d8-4430928abde9@infradead.org
Fixes: 095f1fc4ebf3 ("mempolicy: rework shmem mpol parsing and display")
Reported-by: Entropy Moe <3ntr0py1337@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mempolicy.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/mm/mempolicy.c~mm-mempolicy-require-at-least-one-nodeid-for-mpol_preferred
+++ a/mm/mempolicy.c
@@ -2897,7 +2897,9 @@ int mpol_parse_str(char *str, struct mem
 	switch (mode) {
 	case MPOL_PREFERRED:
 		/*
-		 * Insist on a nodelist of one node only
+		 * Insist on a nodelist of one node only, although later
+		 * we use first_node(nodes) to grab a single node, so here
+		 * nodelist (or nodes) cannot be empty.
 		 */
 		if (nodelist) {
 			char *rest = nodelist;
@@ -2905,6 +2907,8 @@ int mpol_parse_str(char *str, struct mem
 				rest++;
 			if (*rest)
 				goto out;
+			if (nodes_empty(nodes))
+				goto out;
 		}
 		break;
 	case MPOL_INTERLEAVE:
_

Patches currently in -mm which might be from rdunlap@infradead.org are

mm-mempolicy-require-at-least-one-nodeid-for-mpol_preferred.patch
mm-hugetlbc-fix-printk-format-warning-for-32-bit-phys_addr_t.patch
bus-mhi-fix-printk-format-for-size_t.patch