Add more assertions to esc_for_log to please the clangalyzer.

src/common/util.c

@@ -1208,9 +1208,14 @@ esc_for_log(const char *s)
     }
   }
 
+  tor_assert(len <= SSIZE_MAX);
+
   result = outp = tor_malloc(len);
   *outp++ = '\"';
   for (cp = s; *cp; ++cp) {
+    /* This assertion should always succeed, since we will write at least
+     * one char here, and two chars for closing quote and nul later */
+    tor_assert((outp-result) < (ssize_t)len-2);
     switch (*cp) {
       case '\\':
       case '\"':
@@ -1234,6 +1239,7 @@ esc_for_log(const char *s)
         if (TOR_ISPRINT(*cp) && ((uint8_t)*cp)<127) {
           *outp++ = *cp;
         } else {
+          tor_assert((outp-result) < (ssize_t)len-4);
           tor_snprintf(outp, 5, "\\%03o", (int)(uint8_t) *cp);
           outp += 4;
         }
@@ -1241,6 +1247,7 @@ esc_for_log(const char *s)
     }
   }
 
+  tor_assert((outp-result) <= (ssize_t)len-2);
   *outp++ = '\"';
   *outp++ = 0;