Fix callout string read overrun; do better with catching these when using

zero-terminated patterns under valgrind.

ChangeLog

@@ -21,15 +21,23 @@ some minor bugs and Perl incompatibilities were fixed, including:
 
   (a) \Q\E in the middle of a quantifier such as A+\Q\E+ is now ignored instead
       of giving an invalid quantifier error.
+
   (b) {0} can now be used after a group in a lookbehind assertion; previously
       this caused an "assertion is not fixed length" error.
+
   (c) Perl always treats (?(DEFINE) as a "define" group, even if a group with 
       the name "DEFINE" exists. PCRE2 now does likewise.
+
   (d) A recursion condition test such as (?(R2)...) must now refer to an 
       existing subpattern.
+
   (e) A conditional recursion test such as (?(R)...) misbehaved if there was a 
       group whose name began with "R".
 
+  (f) When testing zero-terminated patterns under valgrind, the terminating 
+      zero is now marked "no access". This catches bugs that would otherwise
+      show up only with non-zero-terminated patterns.
+       
 One effect of the refactoring is that some error numbers and messages have 
 changed, and the pattern offset given for compiling errors is not always the
 right-most character that has been read. In particular, for a variable-length
@@ -64,6 +72,9 @@ Some bugs in the refactored code were subsequently fixed before release:
   (f) An unterminated repeat at the end of a non-zero-terminated pattern (e.g.
       "{2,2") could cause reading beyond the pattern.
       
+  (g) When reading a callout string, if the end delimiter was at the end of the 
+      pattern one further code unit was read.
+
 4. Back references are now permitted in lookbehind assertions when there are 
 no duplicated group numbers (that is, (?| has not been used), and, if the 
 reference is by name, there is only one group of that name. The referenced

src/pcre2_compile.c

@@ -3436,7 +3436,8 @@ while (ptr < ptrend)
             ptr = startptr;   /* To give a more useful message */
             goto FAILED;
             }
-          if (*ptr == delimiter && (++ptr > ptrend || *ptr != delimiter)) break;
+          if (*ptr == delimiter && (++ptr >= ptrend || *ptr != delimiter)) 
+            break;
           }
 
         calloutlength = (PCRE2_SIZE)(ptr - startptr);
@@ -8827,6 +8828,7 @@ pcre2_compile(PCRE2_SPTR pattern, PCRE2_SIZE patlen, uint32_t options,
 {
 BOOL utf;                             /* Set TRUE for UTF mode */
 BOOL has_lookbehind;                  /* Set TRUE if a lookbehind is found */
+BOOL zero_terminated;                 /* Set TRUE for zero-terminated pattern */
 pcre2_real_code *re = NULL;           /* What we will return */
 compile_block cb;                     /* "Static" compile-time data */
 const uint8_t *tables;                /* Char tables base pointer */
@@ -8901,13 +8903,19 @@ if (ccontext == NULL)
 /* A zero-terminated pattern is indicated by the special length value
 PCRE2_ZERO_TERMINATED. Check for an overlong pattern. */
 
-if (patlen == PCRE2_ZERO_TERMINATED) patlen = PRIV(strlen)(pattern);
+if ((zero_terminated = (patlen == PCRE2_ZERO_TERMINATED)))
+  patlen = PRIV(strlen)(pattern);
+
 if (patlen > ccontext->max_pattern_length)
   {
   *errorptr = ERR88;
   return NULL;
   }
 
+/* From here on, all returns from this function should end up going via the
+EXIT label. */
+
+
 /* ------------ Initialize the "static" compile data -------------- */
 
 tables = (ccontext->tables != NULL)? ccontext->tables : PRIV(default_tables);
@@ -8966,7 +8974,13 @@ for (i = 0; i < 10; i++) cb.small_ref_offset[i] = PCRE2_UNSET;
 /* --------------- Start looking at the pattern --------------- */
 
 /* Check for global one-time option settings at the start of the pattern, and
-remember the offset to the actual regex. */
+remember the offset to the actual regex. With valgrind support, make the
+terminator of a zero-terminated pattern inaccessible. This catches bugs that
+would otherwise only show up for non-zero-terminated patterns. */
+
+#ifdef SUPPORT_VALGRIND
+if (zero_terminated) VALGRIND_MAKE_MEM_NOACCESS(pattern + patlen, CU2BYTES(1));
+#endif
 
 ptr = pattern;
 skipatstart = 0;
@@ -9148,14 +9162,14 @@ if ((options & PCRE2_AUTO_CALLOUT) != 0)
 
 if (parsed_size_needed >= PARSED_PATTERN_DEFAULT_SIZE)
   {
-  cb.parsed_pattern = ccontext->memctl.malloc(
-    (parsed_size_needed + 1) * sizeof(uint32_t),
-      ccontext->memctl.memory_data);
-  if (cb.parsed_pattern == NULL)
+  uint32_t *heap_parsed_pattern = ccontext->memctl.malloc(
+    (parsed_size_needed + 1) * sizeof(uint32_t), ccontext->memctl.memory_data);
+  if (heap_parsed_pattern == NULL)
     {
     *errorptr = ERR21;
-    return NULL;
+    goto EXIT;
     }
+  cb.parsed_pattern = heap_parsed_pattern;
   }
 
 /* Do the parsing scan. */
@@ -9547,12 +9561,16 @@ if ((re->overall_options & PCRE2_NO_START_OPTIMIZE) == 0 &&
   goto HAD_CB_ERROR;
   }
 
-/* Control ends up here in all cases. If memory was obtained for the parsed
+/* Control ends up here in all cases. When running under valgrind, make a 
+pattern's terminating zero defined again. If memory was obtained for the parsed
 version of the pattern, free it before returning. Also free the list of named
 groups if a larger one had to be obtained, and likewise the group information
 vector. */
 
 EXIT:
+#ifdef SUPPORT_VALGRIND
+if (zero_terminated) VALGRIND_MAKE_MEM_DEFINED(pattern + patlen, CU2BYTES(1));
+#endif
 if (cb.parsed_pattern != stack_parsed_pattern)
   ccontext->memctl.free(cb.parsed_pattern, ccontext->memctl.memory_data);
 if (cb.named_group_list_size > NAMED_GROUP_LIST_SIZE)