From: Ken Raeburn <raeburn@mit.edu>
Date: Mon, 21 May 2007 21:44:40 +0000 (+0000)
Subject: Simplify UNIX krb5int_zap_data a little.  Omit volatile cast, just call memset,
X-Git-Tag: krb5-1.7-alpha1~1107
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=659539f21538312c0871ff42e31b826c3f99b72f;p=krb5.git

Simplify UNIX krb5int_zap_data a little.  Omit volatile cast, just call memset,
but for gcc, use a volatile asm afterwards to make the memory appear to be
referenced and deter optimizations that would remove the memset.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@19553 dc483132-0cff-0310-8789-dd5450dbe970
---

diff --git a/src/include/k5-int.h b/src/include/k5-int.h
index 93a0b1abb..0b01026ec 100644
--- a/src/include/k5-int.h
+++ b/src/include/k5-int.h
@@ -684,18 +684,14 @@ krb5_error_code krb5int_pbkdf2_hmac_sha1 (const krb5_data *, unsigned long,
 /* Make this a function eventually?  */
 #ifdef _WIN32
 # define krb5int_zap_data(ptr, len) SecureZeroMemory(ptr, len)
-#elif defined(__palmos__) && !defined(__GNUC__)
-/* CodeWarrior 8.3 complains about passing a pointer to volatile in to
-   memset.  On the other hand, we probably want it for gcc.  */
-# define krb5int_zap_data(ptr, len) memset(ptr, 0, len)
+#elif defined(__GNUC__)
+static inline void krb5int_zap_data(void *ptr, size_t len)
+{
+    memset(ptr, 0, len);
+    asm volatile ("" : : "g" (ptr), "g" (len));
+}
 #else
 # define krb5int_zap_data(ptr, len) memset((volatile void *)ptr, 0, len)
-# if defined(__GNUC__) && defined(__GLIBC__)
-/* GNU libc generates multiple bogus initialization warnings if we
-   pass memset a volatile pointer.  The compiler should do well enough
-   with memset even without GNU libc's attempt at optimization.  */
-# undef memset
-# endif
 #endif /* WIN32 */
 #define zap(p,l) krb5int_zap_data(p,l)