dlmalloc: Fix integer overflow in request2size()

req is of type size_t, casting it to long opens the door
for an integer overflow.
Values between LONG_MAX - (SIZE_SZ + MALLOC_ALIGN_MASK) - 1 and LONG_MAX
cause and overflow such that request2size() returns MINSIZE.

Fix by removing the cast.
The origin of the cast is unclear, it's in u-boot and ppcboot since ever
and predates the CVS history.
Doug Lea's original dlmalloc implementation also doesn't have it.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/common/dlmalloc.c b/common/dlmalloc.c
index 1e1602a24decb3ba28154def2de05ab25f8a23b6..48e83da6cbceb394c8381134e235bad6b0252353 100644 (file)
--- a/common/dlmalloc.c
+++ b/common/dlmalloc.c
@@ -386,8 +386,8 @@ nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 /* pad request bytes into a usable size */
 
 #define request2size(req) \
- (((long)((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
-  (long)(MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
+ ((((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) < \
+  (MINSIZE + MALLOC_ALIGN_MASK)) ? MINSIZE : \
    (((req) + (SIZE_SZ + MALLOC_ALIGN_MASK)) & ~(MALLOC_ALIGN_MASK)))
 
 /* Check if m has acceptable alignment */