Make strlncpy() and strlncat() use strlncat() instead of strlen().

This fixes a possible crash when using RPC with unix domain sockets,
reported by Valware.

This also adds a configure check so we use our own strlncat if the
C library does not have one, e.g. some non-Linux.

configure

@@ -6357,6 +6357,19 @@ $as_echo "#define HAVE_SYSLOG /**/" >>confdefs.h
 fi
 done
 
+for ac_func in strnlen
+do :
+  ac_fn_c_check_func "$LINENO" "strnlen" "ac_cv_func_strnlen"
+if test "x$ac_cv_func_strnlen" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_STRNLEN 1
+_ACEOF
+
+$as_echo "#define HAVE_STRNLEN /**/" >>confdefs.h
+
+fi
+done
+
 
 
 

configure.ac

@@ -405,6 +405,7 @@ AC_CHECK_FUNCS([setproctitle],
 
 AC_CHECK_FUNCS(explicit_bzero,AC_DEFINE([HAVE_EXPLICIT_BZERO], [], [Define if you have explicit_bzero]))
 AC_CHECK_FUNCS(syslog,AC_DEFINE([HAVE_SYSLOG], [], [Define if you have syslog]))
+AC_CHECK_FUNCS(strnlen,AC_DEFINE([HAVE_STRNLEN], [], [Define if you have strnlen]))
 AC_SUBST(CRYPTOLIB)
 AC_SUBST(MODULEFLAGS)
 AC_SUBST(DYNAMIC_LDFLAGS)

include/h.h

@@ -454,6 +454,9 @@ extern MODVAR long SNO_SNOTICE;
 extern MODVAR long SNO_SPAMF;
 extern MODVAR long SNO_OPER;
 
+#ifndef HAVE_STRNLEN
+extern size_t strnlen(const char *s, size_t maxlen);
+#endif
 #ifndef HAVE_STRLCPY
 extern size_t strlcpy(char *dst, const char *src, size_t size);
 #endif

include/setup.h.in

@@ -121,6 +121,9 @@
 /* Define to 1 if you have the `strlncpy' function. */
 #undef HAVE_STRLNCPY
 
+/* Define to 1 if you have the `strnlen' function. */
+#undef HAVE_STRNLEN
+
 /* Define to 1 if you have the `syslog' function. */
 #undef HAVE_SYSLOG
 

src/support.c

@@ -155,6 +155,14 @@ void stripcrlf(char *c)
 	}
 }
 
+#ifndef HAVE_STRNLEN
+size_t strnlen(const char *s, size_t maxlen)
+{
+	const char *end = memchr (s, 0, maxlen);
+	return end ? (size_t)(end - s) : maxlen;
+}
+#endif
+
 #ifndef HAVE_STRLCPY
 /** BSD'ish strlcpy().
  * The strlcpy() function copies up to size-1 characters from the
@@ -182,13 +190,11 @@ size_t strlcpy(char *dst, const char *src, size_t size)
  */
 size_t strlncpy(char *dst, const char *src, size_t size, size_t n)
 {
-	size_t len = strlen(src);
+	size_t len = strnlen(src, n);
 	size_t ret = len;
 
 	if (size <= 0)
 		return 0;
-	if (len > n)
-		len = n;
 	if (len >= size)
 		len = size - 1;
 	memcpy(dst, src, len);
@@ -230,15 +236,12 @@ size_t strlcat(char *dst, const char *src, size_t size)
 size_t strlncat(char *dst, const char *src, size_t size, size_t n)
 {
 	size_t len1 = strlen(dst);
-	size_t len2 = strlen(src);
+	size_t len2 = strnlen(src, n);
 	size_t ret = len1 + len2;
 
 	if (size <= len1)
 		return size;
 		
-	if (len2 > n)
-		len2 = n;
-
 	if (len1 + len2 >= size)
 		len2 = size - (len1 + 1);