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Diffstat (limited to 'lib/isc/regex.c')
| -rw-r--r-- | lib/isc/regex.c | 436 |
1 files changed, 436 insertions, 0 deletions
diff --git a/lib/isc/regex.c b/lib/isc/regex.c new file mode 100644 index 0000000..f7a3f5e --- /dev/null +++ b/lib/isc/regex.c @@ -0,0 +1,436 @@ +/* + * Copyright (C) Internet Systems Consortium, Inc. ("ISC") + * + * SPDX-License-Identifier: MPL-2.0 + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, you can obtain one at https://mozilla.org/MPL/2.0/. + * + * See the COPYRIGHT file distributed with this work for additional + * information regarding copyright ownership. + */ + +#include <stdbool.h> + +#include <isc/file.h> +#include <isc/print.h> +#include <isc/regex.h> +#include <isc/string.h> + +#if VALREGEX_REPORT_REASON +#define FAIL(x) \ + do { \ + reason = (x); \ + goto error; \ + } while (0) +#else /* if VALREGEX_REPORT_REASON */ +#define FAIL(x) goto error +#endif /* if VALREGEX_REPORT_REASON */ + +/* + * Validate the regular expression 'C' locale. + */ +int +isc_regex_validate(const char *c) { + enum { + none, + parse_bracket, + parse_bound, + parse_ce, + parse_ec, + parse_cc + } state = none; + /* Well known character classes. */ + const char *cc[] = { ":alnum:", ":digit:", ":punct:", ":alpha:", + ":graph:", ":space:", ":blank:", ":lower:", + ":upper:", ":cntrl:", ":print:", ":xdigit:" }; + bool seen_comma = false; + bool seen_high = false; + bool seen_char = false; + bool seen_ec = false; + bool seen_ce = false; + bool have_atom = false; + int group = 0; + int range = 0; + int sub = 0; + bool empty_ok = false; + bool neg = false; + bool was_multiple = false; + unsigned int low = 0; + unsigned int high = 0; + const char *ccname = NULL; + int range_start = 0; +#if VALREGEX_REPORT_REASON + const char *reason = ""; +#endif /* if VALREGEX_REPORT_REASON */ + + if (c == NULL || *c == 0) { + FAIL("empty string"); + } + + while (c != NULL && *c != 0) { + switch (state) { + case none: + switch (*c) { + case '\\': /* make literal */ + ++c; + switch (*c) { + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': + case '8': + case '9': + if ((*c - '0') > sub) { + FAIL("bad back reference"); + } + have_atom = true; + was_multiple = false; + break; + case 0: + FAIL("escaped end-of-string"); + default: + goto literal; + } + ++c; + break; + case '[': /* bracket start */ + ++c; + neg = false; + was_multiple = false; + seen_char = false; + state = parse_bracket; + break; + case '{': /* bound start */ + switch (c[1]) { + case '0': + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': + case '8': + case '9': + if (!have_atom) { + FAIL("no atom"); + } + if (was_multiple) { + FAIL("was multiple"); + } + seen_comma = false; + seen_high = false; + low = high = 0; + state = parse_bound; + break; + default: + goto literal; + } + ++c; + have_atom = true; + was_multiple = true; + break; + case '}': + goto literal; + case '(': /* group start */ + have_atom = false; + was_multiple = false; + empty_ok = true; + ++group; + ++sub; + ++c; + break; + case ')': /* group end */ + if (group && !have_atom && !empty_ok) { + FAIL("empty alternative"); + } + have_atom = true; + was_multiple = false; + if (group != 0) { + --group; + } + ++c; + break; + case '|': /* alternative separator */ + if (!have_atom) { + FAIL("no atom"); + } + have_atom = false; + empty_ok = false; + was_multiple = false; + ++c; + break; + case '^': + case '$': + have_atom = true; + was_multiple = true; + ++c; + break; + case '+': + case '*': + case '?': + if (was_multiple) { + FAIL("was multiple"); + } + if (!have_atom) { + FAIL("no atom"); + } + have_atom = true; + was_multiple = true; + ++c; + break; + case '.': + default: + literal: + have_atom = true; + was_multiple = false; + ++c; + break; + } + break; + case parse_bound: + switch (*c) { + case '0': + case '1': + case '2': + case '3': + case '4': + case '5': + case '6': + case '7': + case '8': + case '9': + if (!seen_comma) { + low = low * 10 + *c - '0'; + if (low > 255) { + FAIL("lower bound too big"); + } + } else { + seen_high = true; + high = high * 10 + *c - '0'; + if (high > 255) { + FAIL("upper bound too big"); + } + } + ++c; + break; + case ',': + if (seen_comma) { + FAIL("multiple commas"); + } + seen_comma = true; + ++c; + break; + default: + case '{': + FAIL("non digit/comma"); + case '}': + if (seen_high && low > high) { + FAIL("bad parse bound"); + } + seen_comma = false; + state = none; + ++c; + break; + } + break; + case parse_bracket: + switch (*c) { + case '^': + if (seen_char || neg) { + goto inside; + } + neg = true; + ++c; + break; + case '-': + if (range == 2) { + goto inside; + } + if (!seen_char) { + goto inside; + } + if (range == 1) { + FAIL("bad range"); + } + range = 2; + ++c; + break; + case '[': + ++c; + switch (*c) { + case '.': /* collating element */ + if (range != 0) { + --range; + } + ++c; + state = parse_ce; + seen_ce = false; + break; + case '=': /* equivalence class */ + if (range == 2) { + FAIL("equivalence class in " + "range"); + } + ++c; + state = parse_ec; + seen_ec = false; + break; + case ':': /* character class */ + if (range == 2) { + FAIL("character class in " + "range"); + } + ccname = c; + ++c; + state = parse_cc; + break; + } + seen_char = true; + break; + case ']': + if (!c[1] && !seen_char) { + FAIL("unfinished brace"); + } + if (!seen_char) { + goto inside; + } + ++c; + range = 0; + have_atom = true; + state = none; + break; + default: + inside: + seen_char = true; + if (range == 2 && (*c & 0xff) < range_start) { + FAIL("out of order range"); + } + if (range != 0) { + --range; + } + range_start = *c & 0xff; + ++c; + break; + } + break; + case parse_ce: + switch (*c) { + case '.': + ++c; + switch (*c) { + case ']': + if (!seen_ce) { + FAIL("empty ce"); + } + ++c; + state = parse_bracket; + break; + default: + if (seen_ce) { + range_start = 256; + } else { + range_start = '.'; + } + seen_ce = true; + break; + } + break; + default: + if (seen_ce) { + range_start = 256; + } else { + range_start = *c; + } + seen_ce = true; + ++c; + break; + } + break; + case parse_ec: + switch (*c) { + case '=': + ++c; + switch (*c) { + case ']': + if (!seen_ec) { + FAIL("no ec"); + } + ++c; + state = parse_bracket; + break; + default: + seen_ec = true; + break; + } + break; + default: + seen_ec = true; + ++c; + break; + } + break; + case parse_cc: + switch (*c) { + case ':': + ++c; + switch (*c) { + case ']': { + unsigned int i; + bool found = false; + for (i = 0; + i < sizeof(cc) / sizeof(*cc); i++) + { + unsigned int len; + len = strlen(cc[i]); + if (len != + (unsigned int)(c - ccname)) + { + continue; + } + if (strncmp(cc[i], ccname, len)) + { + continue; + } + found = true; + } + if (!found) { + FAIL("unknown cc"); + } + ++c; + state = parse_bracket; + break; + } + default: + break; + } + break; + default: + ++c; + break; + } + break; + } + } + if (group != 0) { + FAIL("group open"); + } + if (state != none) { + FAIL("incomplete"); + } + if (!have_atom) { + FAIL("no atom"); + } + return (sub); + +error: +#if VALREGEX_REPORT_REASON + fprintf(stderr, "%s\n", reason); +#endif /* if VALREGEX_REPORT_REASON */ + return (-1); +} |