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Description: PCRE Call Stack Overflow Vulnerability
Fix compile-time loop for recursive reference within a group
with an indefinite repeat.
Origin: backport, http://vcs.pcre.org/pcre?view=revision&revision=1498
Bug: https://bugs.exim.org/show_bug.cgi?id=1515
Forwarded: not-needed
Last-Update: 2015-09-10
Applied-Upstream: 8.36
--- a/pcre_compile.c
+++ b/pcre_compile.c
@@ -2367,6 +2367,7 @@ for (code = first_significant_code(code
if (c == OP_RECURSE)
{
const pcre_uchar *scode = cd->start_code + GET(code, 1);
+ const pcre_uchar *endgroup = scode;
BOOL empty_branch;
/* Test for forward reference or uncompleted reference. This is disabled
@@ -2381,24 +2382,20 @@ for (code = first_significant_code(code
if (GET(scode, 1) == 0) return TRUE; /* Unclosed */
}
- /* If we are scanning a completed pattern, there are no forward references
- and all groups are complete. We need to detect whether this is a recursive
- call, as otherwise there will be an infinite loop. If it is a recursion,
- just skip over it. Simple recursions are easily detected. For mutual
- recursions we keep a chain on the stack. */
+ /* If the reference is to a completed group, we need to detect whether this
+ is a recursive call, as otherwise there will be an infinite loop. If it is
+ a recursion, just skip over it. Simple recursions are easily detected. For
+ mutual recursions we keep a chain on the stack. */
+ do endgroup += GET(endgroup, 1); while (*endgroup == OP_ALT);
+ if (code >= scode && code <= endgroup) continue; /* Simple recursion */
else
- {
+ {
recurse_check *r = recurses;
- const pcre_uchar *endgroup = scode;
-
- do endgroup += GET(endgroup, 1); while (*endgroup == OP_ALT);
- if (code >= scode && code <= endgroup) continue; /* Simple recursion */
-
for (r = recurses; r != NULL; r = r->prev)
if (r->group == scode) break;
if (r != NULL) continue; /* Mutual recursion */
- }
+ }
/* Completed reference; scan the referenced group, remembering it on the
stack chain to detect mutual recursions. */
--- a/testdata/testinput1
+++ b/testdata/testinput1
@@ -4937,6 +4937,12 @@ however, we need the complication for Pe
/((?(R1)a+|(?1)b))/
aaaabcde
+
+/((?(R)a|(?1)))*/
+ aaa
+
+/((?(R)a|(?1)))+/
+ aaa
/a(*:any
name)/K
--- a/testdata/testoutput1
+++ b/testdata/testoutput1
@@ -8234,6 +8234,16 @@ MK: M
aaaabcde
0: aaaab
1: aaaab
+
+/((?(R)a|(?1)))*/
+ aaa
+ 0: aaa
+ 1: a
+
+/((?(R)a|(?1)))+/
+ aaa
+ 0: aaa
+ 1: a
/a(*:any
name)/K
|
