[Pcre-svn] [1590] code/trunk: Add an internal error if handl…

          http://vcs.pcre.org/viewvc?view=rev&revision=1590
Author:   ph10
Date:     2015-08-10 15:38:34 +0100 (Mon, 10 Aug 2015)
Log Message:
-----------
Add an internal error if handling forward referencing recursion calls has gone 
wrong.

Modified Paths:
--------------
    code/trunk/ChangeLog
    code/trunk/pcre_compile.c

Modified: code/trunk/ChangeLog
===================================================================
--- code/trunk/ChangeLog    2015-08-10 14:19:06 UTC (rev 1589)
+++ code/trunk/ChangeLog    2015-08-10 14:38:34 UTC (rev 1590)
@@ -120,6 +120,11 @@
 31. Added a check for integer overflow in conditions (?(<digits>) and
     (?(R<digits>). This omission was discovered by Karl Skomski with the LLVM
     fuzzer.
+    
+32. Handling recursive references such as (?2) when the reference is to a group 
+    later in the pattern uses code that is very hacked about and error-prone.
+    It has been re-written for PCRE2. Here in PCRE1, a check has been added to
+    give an internal error if it is obvious that compiling has gone wrong.

Modified: code/trunk/pcre_compile.c
===================================================================
--- code/trunk/pcre_compile.c    2015-08-10 14:19:06 UTC (rev 1589)
+++ code/trunk/pcre_compile.c    2015-08-10 14:38:34 UTC (rev 1590)
@@ -464,7 +464,7 @@
   "range out of order in character class\0"
   "nothing to repeat\0"
   /* 10 */
-  "operand of unlimited repeat could match the empty string\0"  /** DEAD **/
+  "internal error: invalid forward reference offset\0"
   "internal error: unexpected repeat\0"
   "unrecognized character after (? or (?-\0"
   "POSIX named classes are supported only within a class\0"
@@ -9434,6 +9434,16 @@
     int offset, recno;
     cd->hwm -= LINK_SIZE;
     offset = GET(cd->hwm, 0);
+    
+    /* Check that the hwm handling hasn't gone wrong. This whole area is
+    rewritten in PCRE2 because there are some obscure cases. */ 
+     
+    if (offset == 0 || codestart[offset-1] != OP_RECURSE)
+      {
+      errorcode = ERR10; 
+      break;
+      }  
+ 
     recno = GET(codestart, offset);
     if (recno != prev_recno)
       {