suricata/src/detect-nocase.c

/* Copyright (C) 2007-2010 Open Information Security Foundation
 *
 * You can copy, redistribute or modify this Program under the terms of
 * the GNU General Public License version 2 as published by the Free
 * Software Foundation.
 *
 * 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
 * version 2 along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

/**
 * \file
 *
 * \author Victor Julien <victor@inliniac.net>
 *
 * Implements the nocase keyword
 */

#include "suricata-common.h"
#include "decode.h"

#include "detect.h"
#include "detect-parse.h"

#include "flow-var.h"

#include "detect-content.h"
#include "detect-uricontent.h"
#include "detect-pcre.h"
#include "detect-http-client-body.h"
#include "detect-http-cookie.h"
#include "detect-http-header.h"
#include "detect-http-method.h"
#include "detect-http-uri.h"

#include "util-debug.h"

static int DetectNocaseSetup (DetectEngineCtx *, Signature *, char *);

void DetectNocaseRegister (void) {
    sigmatch_table[DETECT_NOCASE].name = "nocase";
    sigmatch_table[DETECT_NOCASE].Match = NULL;
    sigmatch_table[DETECT_NOCASE].Setup = DetectNocaseSetup;
    sigmatch_table[DETECT_NOCASE].Free  = NULL;
    sigmatch_table[DETECT_NOCASE].RegisterTests = NULL;

    sigmatch_table[DETECT_NOCASE].flags |= SIGMATCH_NOOPT;
    sigmatch_table[DETECT_NOCASE].flags |= SIGMATCH_PAYLOAD;
}

/**
 *  \internal
 *  \brief get the last pattern sigmatch that supports nocase:
 *         content, uricontent, http_client_body, http_cookie
 *
 *  \param s signature
 *
 *  \retval sm sigmatch of either content or uricontent that is the last
 *             or NULL if none was found
 */
//static SigMatch *SigMatchGetLastNocasePattern(Signature *s) {
//    SCEnter();
//
//    BUG_ON(s == NULL);
//
//    SigMatch *co_sm = DetectContentGetLastPattern(s->sm_lists_tail[DETECT_SM_LIST_PMATCH]);
//    SigMatch *ur_sm = SigMatchGetLastSM(s->sm_lists_tail[DETECT_SM_LIST_UMATCH], DETECT_URICONTENT);
//    /* http client body SigMatch */
//    SigMatch *hcbd_sm = SigMatchGetLastSM(s->sm_lists_tail[DETECT_SM_LIST_AMATCH], DETECT_AL_HTTP_CLIENT_BODY);
//    /* http cookie SigMatch */
//    SigMatch *hcd_sm = SigMatchGetLastSM(s->sm_lists_tail[DETECT_SM_LIST_AMATCH], DETECT_AL_HTTP_COOKIE);
//    /* http header SigMatch */
//    SigMatch *hhd_sm = SigMatchGetLastSM(s->sm_lists_tail[DETECT_SM_LIST_AMATCH], DETECT_AL_HTTP_HEADER);
//    /* http method SigMatch */
//    SigMatch *hmd_sm = SigMatchGetLastSM(s->sm_lists_tail[DETECT_SM_LIST_AMATCH], DETECT_AL_HTTP_METHOD);
//
//    SigMatch *temp_sm = NULL;
//
//    SigMatch **sm_list = NULL;
//    uint8_t sm_list_count = 0;
//
//    if (co_sm != NULL) {
//        sm_list_count++;
//        if ( (sm_list = SCRealloc(sm_list, sizeof(SigMatch *) * sm_list_count)) == NULL) {
//            SCLogError(SC_ERR_FATAL, "Fatal error encountered in SigMatchGetLastNocasePattern. Exiting...");
//            exit(EXIT_FAILURE);
//        }
//        sm_list[sm_list_count - 1] = co_sm;
//    }
//    if (ur_sm != NULL) {
//        sm_list_count++;
//        if ( (sm_list = SCRealloc(sm_list, sizeof(SigMatch *) * sm_list_count)) == NULL) {
//            SCLogError(SC_ERR_FATAL, "Fatal error encountered in SigMatchGetLastNocasePattern. Exiting...");
//            exit(EXIT_FAILURE);
//        }
//        sm_list[sm_list_count - 1] = ur_sm;
//    }
//    if (hcbd_sm != NULL) {
//        sm_list_count++;
//        if ( (sm_list = SCRealloc(sm_list, sizeof(SigMatch *) * sm_list_count)) == NULL) {
//            SCLogError(SC_ERR_FATAL, "Fatal error encountered in SigMatchGetLastNocasePattern. Exiting...");
//            exit(EXIT_FAILURE);
//        }
//        sm_list[sm_list_count - 1] = hcbd_sm;
//    }
//    if (hcd_sm != NULL) {
//        sm_list_count++;
//        if ( (sm_list = SCRealloc(sm_list, sizeof(SigMatch *) * sm_list_count)) == NULL) {
//            SCLogError(SC_ERR_FATAL, "Fatal error encountered in SigMatchGetLastNocasePattern. Exiting...");
//            exit(EXIT_FAILURE);
//        }
//        sm_list[sm_list_count - 1] = hcd_sm;
//    }
//    if (hhd_sm != NULL) {
//        sm_list_count++;
//        if ( (sm_list = SCRealloc(sm_list, sizeof(SigMatch *) * sm_list_count)) == NULL) {
//            SCLogError(SC_ERR_FATAL, "Fatal error encountered in SigMatchGetLastNocasePattern. Exiting...");
//            exit(EXIT_FAILURE);
//        }
//        sm_list[sm_list_count - 1] = hhd_sm;
//    }
//
//    if (hmd_sm != NULL) {
//        sm_list_count++;
//        if ( (sm_list = SCRealloc(sm_list, sizeof(SigMatch *) * sm_list_count)) == NULL) {
//            SCLogError(SC_ERR_FATAL, "Fatal error encountered in SigMatchGetLastNocasePattern. Exiting...");
//            exit(EXIT_FAILURE);
//        }
//        sm_list[sm_list_count - 1] = hmd_sm;
//    }
//
//    if (sm_list_count == 0)
//        SCReturnPtr(NULL, "SigMatch");
//
//    /* find the highest idx sm, so we apply to the last sm that we support */
//    int i = 0, j = 0;
//    int swapped = 1;
//    while (swapped) {
//        swapped = 0;
//        for (j = i; j < sm_list_count - 1; j++) {
//            if (sm_list[j]->idx < sm_list[j + 1]->idx) {
//                temp_sm = sm_list[j];
//                sm_list[j] = sm_list[j + 1];
//                sm_list[j + 1] = temp_sm;
//                swapped = 1;
//                i++;
//            }
//        }
//    }
//
//    temp_sm = sm_list[0];
//    SCFree(sm_list);
//
//    SCReturnPtr(temp_sm, "SigMatch");
//}

/**
 *  \internal
 *  \brief Apply the nocase keyword to the last pattern match, either content or uricontent
 *  \param det_ctx detection engine ctx
 *  \param s signature
 *  \param nullstr should be null
 *  \retval 0 ok
 *  \retval -1 failure
 */
static int DetectNocaseSetup (DetectEngineCtx *de_ctx, Signature *s, char *nullstr)
{
    SCEnter();

    if (nullstr != NULL) {
        SCLogError(SC_ERR_INVALID_VALUE, "nocase has value");
        SCReturnInt(-1);
    }

    /* Search for the first previous SigMatch that supports nocase */
    SigMatch *pm = SigMatchGetLastSMFromLists(s, 20,
            DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_PMATCH],
            DETECT_URICONTENT, s->sm_lists_tail[DETECT_SM_LIST_UMATCH],
            DETECT_AL_HTTP_CLIENT_BODY, s->sm_lists_tail[DETECT_SM_LIST_HCBDMATCH],
            DETECT_AL_HTTP_SERVER_BODY, s->sm_lists_tail[DETECT_SM_LIST_HSBDMATCH],
            DETECT_AL_HTTP_HEADER, s->sm_lists_tail[DETECT_SM_LIST_HHDMATCH],
            DETECT_AL_HTTP_RAW_HEADER, s->sm_lists_tail[DETECT_SM_LIST_HRHDMATCH],
            DETECT_AL_HTTP_METHOD, s->sm_lists_tail[DETECT_SM_LIST_HMDMATCH],
            DETECT_AL_HTTP_RAW_URI, s->sm_lists_tail[DETECT_SM_LIST_HRUDMATCH],
            DETECT_AL_HTTP_STAT_MSG, s->sm_lists_tail[DETECT_SM_LIST_HSMDMATCH],
            DETECT_AL_HTTP_COOKIE, s->sm_lists_tail[DETECT_SM_LIST_HCDMATCH]);
    if (pm == NULL) {
        SCLogError(SC_ERR_NOCASE_MISSING_PATTERN, "\"nocase\" needs a preceeding "
                "content, uricontent, http_client_body, http_server_body, "
                "http_header, http_method, http_uri, http_cookie, "
                "http_raw_uri or http_stat_msg option");
        SCReturnInt(-1);
    }

    DetectContentData *cd = NULL;

    switch (pm->type) {
        case DETECT_CONTENT:
        case DETECT_URICONTENT:
        case DETECT_AL_HTTP_CLIENT_BODY:
        case DETECT_AL_HTTP_SERVER_BODY:
        case DETECT_AL_HTTP_HEADER:
        case DETECT_AL_HTTP_RAW_HEADER:
        case DETECT_AL_HTTP_METHOD:
        case DETECT_AL_HTTP_COOKIE:
        case DETECT_AL_HTTP_RAW_URI:
        case DETECT_AL_HTTP_STAT_MSG:
            cd = (DetectContentData *)pm->ctx;
            if (cd == NULL) {
                SCLogError(SC_ERR_INVALID_ARGUMENT, "invalid argument");
                SCReturnInt(-1);
            }
            cd->flags |= DETECT_CONTENT_NOCASE;
            /* Recreate the context with nocase chars */
            BoyerMooreCtxToNocase(cd->bm_ctx, cd->content, cd->content_len);
            break;
            /* should never happen */
        default:
            SCLogError(SC_ERR_NOCASE_MISSING_PATTERN, "\"nocase\" needs a preceeding "
                    "content, uricontent, http_client_body, http_server_body, "
                    "http_header, http_method, http_uri, http_cookie or "
                    "http_raw_uri option");
            SCReturnInt(-1);
            break;
    }

    SCReturnInt(0);
}