diff options
Diffstat (limited to '')
| -rw-r--r-- | src/lib/regex.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/src/lib/regex.c b/src/lib/regex.c new file mode 100644 index 0000000..64a6dbe --- /dev/null +++ b/src/lib/regex.c @@ -0,0 +1,390 @@ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA + */ + +/** + * @file lib/regex.c + * @brief regex abstraction functions + * + * @copyright 2014 The FreeRADIUS server project + * @copyright 2014 Arran Cudbard-Bell <a.cudbardb@freeradius.org> + */ + +#ifdef HAVE_REGEX +#include <freeradius-devel/libradius.h> +#include <freeradius-devel/regex.h> + +/* + * Wrapper functions for libpcre. Much more powerful, and guaranteed + * to be binary safe but require libpcre. + */ +# ifdef HAVE_PCRE +/** Free regex_t structure + * + * Calls libpcre specific free functions for the expression and study. + * + * @param preg to free. + */ +static int _regex_free(regex_t *preg) +{ + if (preg->compiled) { + pcre_free(preg->compiled); + preg->compiled = NULL; + } + + if (preg->extra) { +#ifdef PCRE_CONFIG_JIT + pcre_free_study(preg->extra); +#else + pcre_free(preg->extra); +#endif + preg->extra = NULL; + } + + return 0; +} + +/* + * Replace the libpcre malloc and free functions with + * talloc wrappers. This allows us to use the subcapture copy + * functions and just reparent the memory allocated. + */ +static void *_pcre_malloc(size_t to_alloc) +{ + return talloc_array(NULL, uint8_t, to_alloc); +} + +static void _pcre_free(void *to_free) +{ + talloc_free(to_free); +} + +/** Wrapper around pcre_compile + * + * Allows the rest of the code to do compilations using one function signature. + * + * @note Compiled expression must be freed with talloc_free. + * + * @param out Where to write out a pointer to the structure containing the compiled expression. + * @param pattern to compile. + * @param len of pattern. + * @param ignore_case whether to do case insensitive matching. + * @param multiline If true $ matches newlines. + * @param subcaptures Whether to compile the regular expression to store subcapture + * data. + * @param runtime If false run the pattern through the PCRE JIT to convert it to machine code. + * This trades startup time (longer) for runtime performance (better). + * @return >= 1 on success, <= 0 on error. Negative value is offset of parse error. + */ +ssize_t regex_compile(TALLOC_CTX *ctx, regex_t **out, char const *pattern, size_t len, + bool ignore_case, bool multiline, bool subcaptures, bool runtime) +{ + char const *error; + int offset; + int cflags = 0; + regex_t *preg; + + static bool setup = false; + + /* + * Lets us use subcapture copy + */ + if (!setup) { + pcre_malloc = _pcre_malloc; + pcre_free = _pcre_free; + setup = true; + } + + *out = NULL; + + if (len == 0) { + fr_strerror_printf("Empty expression"); + return 0; + } + + if (ignore_case) cflags |= PCRE_CASELESS; + if (multiline) cflags |= PCRE_MULTILINE; + if (!subcaptures) cflags |= PCRE_NO_AUTO_CAPTURE; + + preg = talloc_zero(ctx, regex_t); + talloc_set_destructor(preg, _regex_free); + + preg->compiled = pcre_compile(pattern, cflags, &error, &offset, NULL); + if (!preg->compiled) { + talloc_free(preg); + fr_strerror_printf("Pattern compilation failed: %s", error); + + return -(ssize_t)offset; + } + if (!runtime) { + preg->precompiled = true; + preg->extra = pcre_study(preg->compiled, PCRE_STUDY_JIT_COMPILE, &error); + if (error) { + talloc_free(preg); + fr_strerror_printf("Pattern study failed: %s", error); + + return 0; + } + } + + *out = preg; + + return len; +} + +static const FR_NAME_NUMBER regex_pcre_error_str[] = { + { "PCRE_ERROR_NOMATCH", PCRE_ERROR_NOMATCH }, + { "PCRE_ERROR_NULL", PCRE_ERROR_NULL }, + { "PCRE_ERROR_BADOPTION", PCRE_ERROR_BADOPTION }, + { "PCRE_ERROR_BADMAGIC", PCRE_ERROR_BADMAGIC }, + { "PCRE_ERROR_UNKNOWN_OPCODE", PCRE_ERROR_UNKNOWN_OPCODE }, + { "PCRE_ERROR_NOMEMORY", PCRE_ERROR_NOMEMORY }, + { "PCRE_ERROR_NOSUBSTRING", PCRE_ERROR_NOSUBSTRING }, + { "PCRE_ERROR_MATCHLIMIT", PCRE_ERROR_MATCHLIMIT }, + { "PCRE_ERROR_CALLOUT", PCRE_ERROR_CALLOUT }, + { "PCRE_ERROR_BADUTF8", PCRE_ERROR_BADUTF8 }, + { "PCRE_ERROR_BADUTF8_OFFSET", PCRE_ERROR_BADUTF8_OFFSET }, + { "PCRE_ERROR_PARTIAL", PCRE_ERROR_PARTIAL }, + { "PCRE_ERROR_BADPARTIAL", PCRE_ERROR_BADPARTIAL }, + { "PCRE_ERROR_INTERNAL", PCRE_ERROR_INTERNAL }, + { "PCRE_ERROR_BADCOUNT", PCRE_ERROR_BADCOUNT }, + { "PCRE_ERROR_DFA_UITEM", PCRE_ERROR_DFA_UITEM }, + { "PCRE_ERROR_DFA_UCOND", PCRE_ERROR_DFA_UCOND }, + { "PCRE_ERROR_DFA_UMLIMIT", PCRE_ERROR_DFA_UMLIMIT }, + { "PCRE_ERROR_DFA_WSSIZE", PCRE_ERROR_DFA_WSSIZE }, + { "PCRE_ERROR_DFA_RECURSE", PCRE_ERROR_DFA_RECURSE }, + { "PCRE_ERROR_RECURSIONLIMIT", PCRE_ERROR_RECURSIONLIMIT }, + { "PCRE_ERROR_NULLWSLIMIT", PCRE_ERROR_NULLWSLIMIT }, + { "PCRE_ERROR_BADNEWLINE", PCRE_ERROR_BADNEWLINE }, + { NULL, 0 } +}; + +/** Wrapper around pcre_exec + * + * @param preg The compiled expression. + * @param subject to match. + * @param len Length of subject. + * @param pmatch Array of match pointers. + * @param nmatch How big the match array is. Updated to number of matches. + * @return -1 on error, 0 on no match, 1 on match. + */ +int regex_exec(regex_t *preg, char const *subject, size_t len, regmatch_t pmatch[], size_t *nmatch) +{ + int ret; + size_t matches; + + /* + * PCRE_NO_AUTO_CAPTURE is a compile time only flag, + * and can't be passed here. + * We rely on the fact that matches has been set to + * 0 as a hint that no subcapture data should be + * generated. + */ + if (!pmatch || !nmatch) { + pmatch = NULL; + if (nmatch) *nmatch = 0; + matches = 0; + } else { + matches = *nmatch; + } + + ret = pcre_exec(preg->compiled, preg->extra, subject, len, 0, 0, (int *)pmatch, matches * 3); + if (ret < 0) { + if (ret == PCRE_ERROR_NOMATCH) return 0; + + fr_strerror_printf("regex evaluation failed with code (%i): %s", ret, + fr_int2str(regex_pcre_error_str, ret, "<INVALID>")); + return -1; + } + + /* + * 0 signifies more offsets than we provided space for, + * so don't touch nmatches. + */ + if (nmatch && (ret > 0)) *nmatch = ret; + + return 1; +} +/* + * Wrapper functions for POSIX like, and extended regular + * expressions. These use the system regex library. + */ +# else +/** Free heap allocated regex_t structure + * + * Heap allocation of regex_t is needed so regex_compile has the same signature with + * POSIX or libpcre. + * + * @param preg to free. + */ +static int _regex_free(regex_t *preg) +{ + regfree(preg); + + return 0; +} + +/** Binary safe wrapper around regcomp + * + * If we have the BSD extensions we don't need to do any special work + * if we don't have the BSD extensions we need to check to see if the + * regular expression contains any \0 bytes. + * + * If it does we fail and print the appropriate error message. + * + * @note Compiled expression must be freed with talloc_free. + * + * @param ctx To allocate memory in. + * @param out Where to write out a pointer to the structure containing the + * compiled expression. + * @param pattern to compile. + * @param len of pattern. + * @param ignore_case Whether the match should be case ignore_case. + * @param multiline If true $ matches newlines. + * @param subcaptures Whether to compile the regular expression to store subcapture + * data. + * @param runtime Whether the compilation is being done at runtime. + * @return >= 1 on success, <= 0 on error. Negative value is offset of parse error. + * With POSIX regex we only give the correct offset for embedded \0 errors. + */ +ssize_t regex_compile(TALLOC_CTX *ctx, regex_t **out, char const *pattern, size_t len, + bool ignore_case, bool multiline, bool subcaptures, UNUSED bool runtime) +{ + int ret; + int cflags = REG_EXTENDED; + regex_t *preg; + + if (len == 0) { + fr_strerror_printf("Empty expression"); + return 0; + } + + if (ignore_case) cflags |= REG_ICASE; + if (multiline) cflags |= REG_NEWLINE; + if (!subcaptures) cflags |= REG_NOSUB; + +#ifndef HAVE_REGNCOMP + { + char const *p; + + p = pattern; + p += strlen(pattern); + + if ((size_t)(p - pattern) != len) { + fr_strerror_printf("Found null in pattern at offset %zu. Pattern unsafe for compilation", + (p - pattern)); + return -(p - pattern); + } + + preg = talloc_zero(ctx, regex_t); + if (!preg) return 0; + + ret = regcomp(preg, pattern, cflags); + } +#else + preg = talloc_zero(ctx, regex_t); + if (!preg) return 0; + ret = regncomp(preg, pattern, len, cflags); +#endif + if (ret != 0) { + char errbuf[128]; + + regerror(ret, preg, errbuf, sizeof(errbuf)); + fr_strerror_printf("Pattern compilation failed: %s", errbuf); + + talloc_free(preg); + + return 0; /* POSIX expressions don't give us the failure offset */ + } + + talloc_set_destructor(preg, _regex_free); + *out = preg; + + return len; +} + +/** Binary safe wrapper around regexec + * + * If we have the BSD extensions we don't need to do any special work + * If we don't have the BSD extensions we need to check to see if the + * value to be compared contains any \0 bytes. + * + * If it does, we fail and print the appropriate error message. + * + * @param preg The compiled expression. + * @param subject to match. + * @param pmatch Array of match pointers. + * @param nmatch How big the match array is. Updated to number of matches. + * @return -1 on error, 0 on no match, 1 on match. + */ +int regex_exec(regex_t *preg, char const *subject, size_t len, regmatch_t pmatch[], size_t *nmatch) +{ + int ret; + size_t matches; + + /* + * Disable capturing + */ + if (!pmatch || !nmatch) { + pmatch = NULL; + if (nmatch) *nmatch = 0; + matches = 0; + } else { + /* regexec does not seem to initialise unused elements */ + matches = *nmatch; + memset(pmatch, 0, sizeof(pmatch[0]) * matches); + } + +#ifndef HAVE_REGNEXEC + { + char const *p; + + p = subject; + p += strlen(subject); + + if ((size_t)(p - subject) != len) { + fr_strerror_printf("Found null in subject at offset %zu. String unsafe for evaluation", + (p - subject)); + return -1; + } + ret = regexec(preg, subject, matches, pmatch, 0); + } +#else + ret = regnexec(preg, subject, len, matches, pmatch, 0); +#endif + if (ret != 0) { + if (ret != REG_NOMATCH) { + char errbuf[128]; + + regerror(ret, preg, errbuf, sizeof(errbuf)); + + fr_strerror_printf("regex evaluation failed: %s", errbuf); + if (nmatch) *nmatch = 0; + return -1; + } + return 0; + } + + /* + * Update *nmatch to be the maximum number of + * groups that *could* have been populated, + * need to check them later. + */ + if (nmatch && (*nmatch > preg->re_nsub)) *nmatch = preg->re_nsub + 1; + + return 1; +} +# endif +#endif |