mm/nommu.c: add additional check for vread() just like vwrite() has done
authorChen Gang <gang.chen@asianux.com>
Wed, 3 Jul 2013 22:02:36 +0000 (15:02 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 3 Jul 2013 23:07:31 +0000 (16:07 -0700)
vwrite() checks for overflow. vread() should do the same thing.

Since vwrite() checks the source buffer address, vread() should check
the destination buffer address.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Michel Lespinasse <walken@google.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/nommu.c

index 298884dcd6e71e4723a203a82f1613cbfcec19ec..1898b2fe9da5eefdc3b33823a3cd23d2a401118f 100644 (file)
@@ -282,6 +282,10 @@ EXPORT_SYMBOL(vmalloc_to_pfn);
 
 long vread(char *buf, char *addr, unsigned long count)
 {
+       /* Don't allow overflow */
+       if ((unsigned long) buf + count < count)
+               count = -(unsigned long) buf;
+
        memcpy(buf, addr, count);
        return count;
 }