[PATCH] sys_mbind sanity checking

Make sure maxnodes is safe size before calculating nlongs in
get_nodes().

Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[chrisw: fix units, pointed out by Andi]
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 72f402cc9c9af77f6d6c765c166e35d0bb4764ae..6e870ba707c7e1b514bde2c7b4020405dbfa91af 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -524,6 +524,8 @@ static int get_nodes(nodemask_t *nodes, unsigned long __user *nmask,
        nodes_clear(*nodes);
        if (maxnode == 0 || !nmask)
                return 0;
+       if (maxnode > PAGE_SIZE*BITS_PER_BYTE)
+               return -EINVAL;
 
        nlongs = BITS_TO_LONGS(maxnode);
        if ((maxnode % BITS_PER_LONG) == 0)