[tor-commits] [tor/release-0.2.7] Refine the memwipe() arguments check for 18089 a little more.

[nickm at torproject.org]

commit e2efa9e321972709933b6b9a68da035e1a91aa08
Author: Nick Mathewson <nickm at torproject.org>
Date:   Tue Jan 19 08:28:58 2016 -0500

    Refine the memwipe() arguments check for 18089 a little more.
    
    We still silently ignore
         memwipe(NULL, ch, 0);
    and
         memwipe(ptr, ch, 0);  /* for ptr != NULL */
    
    But we now assert on:
         memwipe(NULL, ch, 30);
---
 src/common/crypto.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/common/crypto.c b/src/common/crypto.c
index 4e0b383..8402ca0 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -3030,9 +3030,11 @@ base32_decode(char *dest, size_t destlen, const char *src, size_t srclen)
 void
 memwipe(void *mem, uint8_t byte, size_t sz)
 {
-  if (mem == NULL || sz == 0) {
+  if (sz == 0) {
     return;
   }
+  /* If sz is nonzero, then mem must not be NULL. */
+  tor_assert(mem != NULL);
 
   /* Data this large is likely to be an underflow. */
   tor_assert(sz < SIZE_T_CEILING);