mm/nommu.c: add additional check for vread() just like vwrite() has done

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 <[email protected]> Cc: Al Viro <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Rik van Riel <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
Baughn · Jul 3, 2013 · 9bde916 · 9bde916
1 parent dacbde0
commit 9bde916
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/mm/nommu.c b/mm/nommu.c
@@ -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;
 }