diff options
| -rw-r--r-- | server/util_pcre.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/server/util_pcre.c b/server/util_pcre.c index 53096ea69c..e3ee455837 100644 --- a/server/util_pcre.c +++ b/server/util_pcre.c @@ -484,6 +484,32 @@ AP_DECLARE(int) ap_regexec_len(const ap_regex_t *preg, const char *buff, match_vector_pt ovector = NULL; apr_uint32_t ncaps = (apr_uint32_t)preg->re_nsub + 1; +#ifndef HAVE_PCRE2 + /* This is fine if pcre_exec() gets a vector size smaller than the + * number of capturing groups (it will treat the remaining ones as + * non-capturing), but if the vector is too small to keep track of + * the potential backrefs within the pattern, it will temporarily + * malloc()ate the necessary space anyway. So let's provide a vector + * of at least PCRE_INFO_BACKREFMAX entries (likely zero, otherwise + * the vector is most likely cached already anyway). + * Note that if no captures are to be used by the caller, passing an + * nmatch of zero (thus forcing all groups to be non-capturing) may + * allow for some optimizations and/or less recursion (stack usage) + * with PCRE1, unless backrefs.. + */ + if (ncaps > nmatch) { + int backrefmax = 0; + pcre_fullinfo((const pcre *)preg->re_pcre, NULL, + PCRE_INFO_BACKREFMAX, &backrefmax); + if (backrefmax > 0 && (apr_uint32_t)backrefmax >= nmatch) { + ncaps = (apr_uint32_t)backrefmax + 1; + } + else { + ncaps = nmatch; + } + } +#endif + if (!setup_state(&state, ncaps)) { return AP_REG_ESPACE; } |