[Pcre-svn] [1167] code/trunk: Add underflow check in JIT.

Revision: 1167

          http://www.exim.org/viewvc/pcre2?view=rev&revision=1167
Author:   zherczeg
Date:     2019-09-09 08:12:00 +0100 (Mon, 09 Sep 2019)
Log Message:
-----------
Add underflow check in JIT.

Modified Paths:
--------------
    code/trunk/ChangeLog
    code/trunk/src/pcre2_jit_compile.c

Modified: code/trunk/ChangeLog
===================================================================
--- code/trunk/ChangeLog    2019-09-07 15:27:05 UTC (rev 1166)
+++ code/trunk/ChangeLog    2019-09-09 07:12:00 UTC (rev 1167)
@@ -146,7 +146,10 @@
 31. Installed a .gitignore file on a user's suggestion. When using the svn
 repository with git (through git svn) this helps keep it tidy.

+32. Add underflow check in JIT which may occure when the value of subject
+string pointer is close to 0.

+
Version 10.33 16-April-2019
---------------------------

Modified: code/trunk/src/pcre2_jit_compile.c
===================================================================
--- code/trunk/src/pcre2_jit_compile.c    2019-09-07 15:27:05 UTC (rev 1166)
+++ code/trunk/src/pcre2_jit_compile.c    2019-09-09 07:12:00 UTC (rev 1167)
@@ -5793,12 +5793,16 @@
   {
   OP1(SLJIT_MOV, TMP1, 0, SLJIT_MEM1(SLJIT_SP), common->match_end_ptr);
   OP1(SLJIT_MOV, TMP3, 0, STR_END, 0);
-  OP2(SLJIT_SUB, STR_END, 0, STR_END, 0, SLJIT_IMM, IN_UCHARS(max));
+  OP2(SLJIT_SUB | SLJIT_SET_LESS, STR_END, 0, STR_END, 0, SLJIT_IMM, IN_UCHARS(max));
+  add_jump(compiler, &common->failed_match, JUMP(SLJIT_LESS));
   OP2(SLJIT_SUB | SLJIT_SET_GREATER, SLJIT_UNUSED, 0, STR_END, 0, TMP1, 0);
   CMOV(SLJIT_GREATER, STR_END, TMP1, 0);
   }
 else
-  OP2(SLJIT_SUB, STR_END, 0, STR_END, 0, SLJIT_IMM, IN_UCHARS(max));
+  {
+  OP2(SLJIT_SUB | SLJIT_SET_LESS, STR_END, 0, STR_END, 0, SLJIT_IMM, IN_UCHARS(max));
+  add_jump(compiler, &common->failed_match, JUMP(SLJIT_LESS));
+  }

SLJIT_ASSERT(range_right >= 0);