Problem reported by Hanno Böck in: http://bugs.gnu.org/21513 * lib/regcomp.c (parse_reg_exp): While parsing alternatives, keep track of the set of previously-completed subexpressions available before the first alternative, and restore this set just before parsing each subsequent alternative. This lets us diagnose the invalid back-reference in the ERE '()|\1'. --- ChangeLog | 8 ++++++++ lib/regcomp.c | 4 ++++ 2 files changed, 12 insertions(+)
diff --git a/ChangeLog b/ChangeLog index f846aac..7c83566 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,13 @@ 2015-09-19 Paul Eggert <egg...@cs.ucla.edu> + Diagnose ERE '()|\1' + Problem reported by Hanno Böck in: http://bugs.gnu.org/21513 + * lib/regcomp.c (parse_reg_exp): While parsing alternatives, keep + track of the set of previously-completed subexpressions available + before the first alternative, and restore this set just before + parsing each subsequent alternative. This lets us diagnose the + invalid back-reference in the ERE '()|\1'. + regex: merge patches from libc 2015-09-08 Joseph Myers <jos...@codesourcery.com> diff --git a/lib/regcomp.c b/lib/regcomp.c index f50afb4..4cbb1b2 100644 --- a/lib/regcomp.c +++ b/lib/regcomp.c @@ -2191,6 +2191,7 @@ parse_reg_exp (re_string_t *regexp, regex_t *preg, re_token_t *token, { re_dfa_t *dfa = preg->buffer; bin_tree_t *tree, *branch = NULL; + bitset_word_t initial_bkref_map = dfa->completed_bkref_map; tree = parse_branch (regexp, preg, token, syntax, nest, err); if (BE (*err != REG_NOERROR && tree == NULL, 0)) return NULL; @@ -2201,6 +2202,8 @@ parse_reg_exp (re_string_t *regexp, regex_t *preg, re_token_t *token, if (token->type != OP_ALT && token->type != END_OF_RE && (nest == 0 || token->type != OP_CLOSE_SUBEXP)) { + bitset_word_t accumulated_bkref_map = dfa->completed_bkref_map; + dfa->completed_bkref_map = initial_bkref_map; branch = parse_branch (regexp, preg, token, syntax, nest, err); if (BE (*err != REG_NOERROR && branch == NULL, 0)) { @@ -2208,6 +2211,7 @@ parse_reg_exp (re_string_t *regexp, regex_t *preg, re_token_t *token, postorder (tree, free_tree, NULL); return NULL; } + dfa->completed_bkref_map |= accumulated_bkref_map; } else branch = NULL; -- 2.1.0
