PATCH: [perl #131551] Too deep regex compilation recursion

This patch, started by Yves Orton, and refined in consultation with Tony
Cook, imposes a maximum depth of unclosed left parentheses, at which
point it croaks.  This is to prevent the segfault in the ticket.

The patch adds a variable that can be set to increase or decrease this
limit at run time (actually regex compilation time) should this be
desired, and hence our pre-determined limit of 1000 can be changed if
necessary.

1 files changed, 3 insertions, 0 deletions

diff --git a/regcomp.h b/regcomp.h
index 7a4432e3d6..5002e2b38d 100644
--- a/regcomp.h
+++ b/regcomp.h
@@ -946,6 +946,9 @@ typedef struct _reg_ac_data reg_ac_data;
 #define RE_TRIE_MAXBUF_NAME "\022E_TRIE_MAXBUF"
 #define RE_DEBUG_FLAGS "\022E_DEBUG_FLAGS"
 
+#define RE_COMPILE_RECURSION_INIT 1000
+#define RE_COMPILE_RECURSION_LIMIT "\022E_COMPILE_RECURSION_LIMIT"
+
 /*
 
 RE_DEBUG_FLAGS is used to control what debug output is emitted