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-rw-r--r--src/regex/regcomp.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/src/regex/regcomp.c b/src/regex/regcomp.c
index ac207c89..078f657c 100644
--- a/src/regex/regcomp.c
+++ b/src/regex/regcomp.c
@@ -837,6 +837,10 @@ static reg_errcode_t parse_atom(tre_parse_ctx_t *ctx, const char *s)
node = tre_ast_new_literal(ctx->mem, v, v, ctx->position++);
s--;
break;
+ case '{':
+ /* reject repetitions after empty expression in BRE */
+ if (!ere)
+ return REG_BADRPT;
default:
if (!ere && (unsigned)*s-'1' < 9) {
/* back reference */
@@ -880,10 +884,14 @@ static reg_errcode_t parse_atom(tre_parse_ctx_t *ctx, const char *s)
s++;
break;
case '*':
- case '|':
+ return REG_BADPAT;
case '{':
case '+':
case '?':
+ /* reject repetitions after empty expression in ERE */
+ if (ere)
+ return REG_BADRPT;
+ case '|':
if (!ere)
goto parse_literal;
case 0:
@@ -964,8 +972,9 @@ static reg_errcode_t tre_parse(tre_parse_ctx_t *ctx)
}
parse_iter:
- /* extension: repetitions are accepted after an empty node
- eg. (+), ^*, a$?, a|{2} */
+ /* extension: repetitions are rejected after an empty node
+ eg. (+), |*, {2}, but assertions are not treated as empty
+ so ^* or $? are accepted currently. */
switch (*s) {
case '+':
case '?':