view src/core/ngx_regex.c @ 4162:fb1375e8b68c stable-1.0

Merging r4036, r4055, r4056, r4057, r4058, r4059, r4060, r4061, r4062, r4063, r4064: Ranges related fixes: The "max_ranges" directive. "max_ranges 0" disables ranges support at all, "max_ranges 1" allows the single range, etc. By default number of ranges is unlimited, to be precise, 2^31-1. If client requests more ranges than "max_ranges" permits, nginx disables ranges and returns just the source response. If total size of all ranges is greater than source response size, then nginx disables ranges and returns just the source response. This fix should not affect well-behaving applications but will defeat DoS attempts exploiting malicious byte ranges. Now unsatisfiable ranges are processed according to RFC 2616.
author Igor Sysoev <igor@sysoev.ru>
date Fri, 30 Sep 2011 14:06:08 +0000
parents 169d84ff4064
children 7423800ef437
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>


static void * ngx_libc_cdecl ngx_regex_malloc(size_t size);
static void ngx_libc_cdecl ngx_regex_free(void *p);


static ngx_pool_t  *ngx_pcre_pool;


void
ngx_regex_init(void)
{
    pcre_malloc = ngx_regex_malloc;
    pcre_free = ngx_regex_free;
}


static ngx_inline void
ngx_regex_malloc_init(ngx_pool_t *pool)
{
#if (NGX_THREADS)
    ngx_core_tls_t  *tls;

    if (ngx_threaded) {
        tls = ngx_thread_get_tls(ngx_core_tls_key);
        tls->pool = pool;
        return;
    }

#endif

    ngx_pcre_pool = pool;
}


static ngx_inline void
ngx_regex_malloc_done(void)
{
#if (NGX_THREADS)
    ngx_core_tls_t  *tls;

    if (ngx_threaded) {
        tls = ngx_thread_get_tls(ngx_core_tls_key);
        tls->pool = NULL;
        return;
    }

#endif

    ngx_pcre_pool = NULL;
}


ngx_int_t
ngx_regex_compile(ngx_regex_compile_t *rc)
{
    int           n, erroff;
    char         *p;
    const char   *errstr;
    ngx_regex_t  *re;

    ngx_regex_malloc_init(rc->pool);

    re = pcre_compile((const char *) rc->pattern.data, (int) rc->options,
                      &errstr, &erroff, NULL);

    /* ensure that there is no current pool */
    ngx_regex_malloc_done();

    if (re == NULL) {
        if ((size_t) erroff == rc->pattern.len) {
           rc->err.len = ngx_snprintf(rc->err.data, rc->err.len,
                              "pcre_compile() failed: %s in \"%V\"",
                               errstr, &rc->pattern)
                      - rc->err.data;

        } else {
           rc->err.len = ngx_snprintf(rc->err.data, rc->err.len,
                              "pcre_compile() failed: %s in \"%V\" at \"%s\"",
                               errstr, &rc->pattern, rc->pattern.data + erroff)
                      - rc->err.data;
        }

        return NGX_ERROR;
    }

    rc->regex = re;

    n = pcre_fullinfo(re, NULL, PCRE_INFO_CAPTURECOUNT, &rc->captures);
    if (n < 0) {
        p = "pcre_fullinfo(\"%V\", PCRE_INFO_CAPTURECOUNT) failed: %d";
        goto failed;
    }

    if (rc->captures == 0) {
        return NGX_OK;
    }

    n = pcre_fullinfo(re, NULL, PCRE_INFO_NAMECOUNT, &rc->named_captures);
    if (n < 0) {
        p = "pcre_fullinfo(\"%V\", PCRE_INFO_NAMECOUNT) failed: %d";
        goto failed;
    }

    if (rc->named_captures == 0) {
        return NGX_OK;
    }

    n = pcre_fullinfo(re, NULL, PCRE_INFO_NAMEENTRYSIZE, &rc->name_size);
    if (n < 0) {
        p = "pcre_fullinfo(\"%V\", PCRE_INFO_NAMEENTRYSIZE) failed: %d";
        goto failed;
    }

    n = pcre_fullinfo(re, NULL, PCRE_INFO_NAMETABLE, &rc->names);
    if (n < 0) {
        p = "pcre_fullinfo(\"%V\", PCRE_INFO_NAMETABLE) failed: %d";
        goto failed;
    }

    return NGX_OK;

failed:

    rc->err.len = ngx_snprintf(rc->err.data, rc->err.len, p, &rc->pattern, n)
                  - rc->err.data;
    return NGX_OK;
}


ngx_int_t
ngx_regex_capture_count(ngx_regex_t *re)
{
    int  rc, n;

    n = 0;

    rc = pcre_fullinfo(re, NULL, PCRE_INFO_CAPTURECOUNT, &n);

    if (rc < 0) {
        return (ngx_int_t) rc;
    }

    return (ngx_int_t) n;
}


ngx_int_t
ngx_regex_exec_array(ngx_array_t *a, ngx_str_t *s, ngx_log_t *log)
{
    ngx_int_t         n;
    ngx_uint_t        i;
    ngx_regex_elt_t  *re;

    re = a->elts;

    for (i = 0; i < a->nelts; i++) {

        n = ngx_regex_exec(re[i].regex, s, NULL, 0);

        if (n == NGX_REGEX_NO_MATCHED) {
            continue;
        }

        if (n < 0) {
            ngx_log_error(NGX_LOG_ALERT, log, 0,
                          ngx_regex_exec_n " failed: %i on \"%V\" using \"%s\"",
                          n, s, re[i].name);
            return NGX_ERROR;
        }

        /* match */

        return NGX_OK;
    }

    return NGX_DECLINED;
}


static void * ngx_libc_cdecl
ngx_regex_malloc(size_t size)
{
    ngx_pool_t      *pool;
#if (NGX_THREADS)
    ngx_core_tls_t  *tls;

    if (ngx_threaded) {
        tls = ngx_thread_get_tls(ngx_core_tls_key);
        pool = tls->pool;

    } else {
        pool = ngx_pcre_pool;
    }

#else

    pool = ngx_pcre_pool;

#endif

    if (pool) {
        return ngx_palloc(pool, size);
    }

    return NULL;
}


static void ngx_libc_cdecl
ngx_regex_free(void *p)
{
    return;
}