diff -upk.orig zlib-1.2.3.orig/gzio.c zlib-1.2.3/gzio.c

--- zlib-1.2.3.orig/gzio.c	2005-07-02 15:37:21 +0000

+++ zlib-1.2.3/gzio.c	2005-07-02 15:48:46 +0000

@@ -41,7 +41,7 @@ extern void   free   OF((voidpf ptr));

 #endif

 #define ALLOC(size) malloc(size)

-#define TRYFREE(p) {if (p) free(p);}

+#define TRYFREE(p) {if (p) {free(p); (p) = NULL;}}

 static int const gz_magic[2] = {0x1f, 0x8b}; /* gzip magic header */

@@ -1006,11 +1006,15 @@ const char * ZEXPORT gzerror (file, errn

     if (m == NULL || *m == '\0') m = (char*)ERR_MSG(s->z_err);

     TRYFREE(s->msg);

-    s->msg = (char*)ALLOC(strlen(s->path) + strlen(m) + 3);

+    s->msg = (char*)ALLOC((s->path ? strlen(s->path) + 2 : 0) + strlen(m) + 1);

     if (s->msg == Z_NULL) return (const char*)ERR_MSG(Z_MEM_ERROR);

-    strcpy(s->msg, s->path);

-    strcat(s->msg, ": ");

-    strcat(s->msg, m);

+    if (s->path) {

+        strcpy(s->msg, s->path);

+        strcat(s->msg, ": ");

+        strcat(s->msg, m);

+    } else {

+        strcpy(s->msg, m);

+    }

     return (const char*)s->msg;

 }