commit d03ee98d63748ba0e2225be221b45a250c8c5741
Author:     Fabian Greffrath <fabian@greffrath.com>
AuthorDate: Fri Mar 27 16:26:22 2015 +0100
Commit:     Fabian Greffrath <fabian@greffrath.com>
CommitDate: Fri Mar 27 16:30:46 2015 +0100

    Avoid calling strlen() on a potentially unterminated string

    The src string may be unterminated and the call to strncpy() be
    terminated by reaching dest_size. Instead of calling strlen() on the
    src string, check if it has a NUL byte at the same position as the
    dest string -- if not, the string was truncated.

    Valgrind now gives thumbs up!
---
 src/m_misc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/m_misc.c b/src/m_misc.c
index 2e363412..ab3c7009 100644
--- a/src/m_misc.c
+++ b/src/m_misc.c
@@ -372,12 +372,15 @@ char *M_StringReplace(const char *haystack, const char *needle,

 boolean M_StringCopy(char *dest, const char *src, size_t dest_size)
 {
+    size_t len;
+
     if (dest_size >= 1)
     {
         dest[dest_size - 1] = '\0';
         strncpy(dest, src, dest_size - 1);
     }
-    return strlen(dest) == strlen(src);
+    len = strlen(dest);
+    return src[len] == '\0';
 }

 // Safe string concat function that works like OpenBSD's strlcat().