Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

[karo-tx-linux.git] / lib / string.c

diff --git a/lib/string.c b/lib/string.c
index 2fc20aa06f848fcebd8aa30d238942f5ec399690..ce81aaec38391b0fb68cef2f5ba070c9a520e49e 100644 (file)
--- a/lib/string.c
+++ b/lib/string.c
@@ -58,14 +58,6 @@ int strncasecmp(const char *s1, const char *s2, size_t len)
 }
 EXPORT_SYMBOL(strncasecmp);
 #endif
-#ifndef __HAVE_ARCH_STRNICMP
-#undef strnicmp
-int strnicmp(const char *s1, const char *s2, size_t len)
-{
-       return strncasecmp(s1, s2, len);
-}
-EXPORT_SYMBOL(strnicmp);
-#endif
 
 #ifndef __HAVE_ARCH_STRCASECMP
 int strcasecmp(const char *s1, const char *s2)
@@ -321,12 +313,12 @@ EXPORT_SYMBOL(strchrnul);
  */
 char *strrchr(const char *s, int c)
 {
-       const char *p = s + strlen(s);
-       do {
-           if (*p == (char)c)
-               return (char *)p;
-       } while (--p >= s);
-       return NULL;
+       const char *last = NULL;
+       do {
+               if (*s == (char)c)
+                       last = s;
+       } while (*s++);
+       return (char *)last;
 }
 EXPORT_SYMBOL(strrchr);
 #endif
@@ -598,6 +590,27 @@ void *memset(void *s, int c, size_t count)
 EXPORT_SYMBOL(memset);
 #endif
 
+/**
+ * memzero_explicit - Fill a region of memory (e.g. sensitive
+ *                   keying data) with 0s.
+ * @s: Pointer to the start of the area.
+ * @count: The size of the area.
+ *
+ * Note: usually using memset() is just fine (!), but in cases
+ * where clearing out _local_ data at the end of a scope is
+ * necessary, memzero_explicit() should be used instead in
+ * order to prevent the compiler from optimising away zeroing.
+ *
+ * memzero_explicit() doesn't need an arch-specific version as
+ * it just invokes the one of memset() implicitly.
+ */
+void memzero_explicit(void *s, size_t count)
+{
+       memset(s, 0, count);
+       OPTIMIZER_HIDE_VAR(s);
+}
+EXPORT_SYMBOL(memzero_explicit);
+
 #ifndef __HAVE_ARCH_MEMCPY
 /**
  * memcpy - Copy one area of memory to another