File memcached-CVE-2019-15026.patch of Package memcached.11123

Index: memcached-1.5.6/memcached.c
===================================================================
--- memcached-1.5.6.orig/memcached.c	2019-09-03 12:01:54.762376784 +0200
+++ memcached-1.5.6/memcached.c	2019-09-03 12:24:51.486326057 +0200
@@ -3273,6 +3273,7 @@ static void conn_to_str(const conn *c, c
         struct sockaddr *addr = (void *)&c->request_addr;
         int af;
         unsigned short port = 0;
+        size_t pathlen = 0;
 
         /* For listen ports and idle UDP ports, show listen address */
         if (c->state == conn_listening ||
@@ -3314,10 +3315,27 @@ static void conn_to_str(const conn *c, c
                 break;
 
             case AF_UNIX:
+                // this strncpy call originally could piss off an address
+                // sanitizer; we supplied the size of the dest buf as a limiter,
+                // but optimized versions of strncpy could read past the end of
+                // *src while looking for a null terminator. Since buf and
+                // sun_path here are both on the stack they could even overlap,
+                // which is "undefined". In all OSS versions of strncpy I could
+                // find this has no effect; it'll still only copy until the first null
+                // terminator is found. Thus it's possible to get the OS to
+                // examine past the end of sun_path but it's unclear to me if this
+                // can cause any actual problem.
+                //
+                // We need a safe_strncpy util function but I'll punt on figuring
+                // that out for now.
+                pathlen = sizeof(((struct sockaddr_un *)addr)->sun_path);
+                if (MAXPATHLEN <= pathlen) {
+                    pathlen = MAXPATHLEN - 1;
+                }
                 strncpy(addr_text,
                         ((struct sockaddr_un *)addr)->sun_path,
-                        sizeof(addr_text) - 1);
-                addr_text[sizeof(addr_text)-1] = '\0';
+                        pathlen);
+                addr_text[pathlen] = '\0';
                 protoname = "unix";
                 break;
         }