suricata/src/detect-http-stat-msg.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.
 */

/**
 * \ingroup httplayer
 *
 * @{
 */


/**
 * \file
 *
 * \author Gurvinder Singh <gurvindersinghdahiya@gmail.com>
 * \author Anoop Saldanha <anoopsaldanha@gmail.com>
 *
 * Implements the http_stat_msg keyword
 */

#include "suricata-common.h"
#include "threads.h"
#include "debug.h"
#include "decode.h"
#include "detect.h"

#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-content.h"
#include "detect-pcre.h"
#include "detect-engine-mpm.h"

#include "flow.h"
#include "flow-var.h"
#include "flow-util.h"

#include "util-debug.h"
#include "util-error.h"
#include "util-unittest.h"
#include "util-unittest-helper.h"
#include "util-spm.h"
#include "util-print.h"

#include "app-layer.h"
#include "app-layer-parser.h"

#include "app-layer-htp.h"
#include "detect-http-stat-msg.h"
#include "detect-engine-hsmd.h"
#include "stream-tcp-private.h"
#include "stream-tcp.h"

static int DetectHttpStatMsgSetup(DetectEngineCtx *, Signature *, const char *);
static void DetectHttpStatMsgRegisterTests(void);
static void DetectHttpStatMsgSetupCallback(Signature *s);
static int g_http_stat_msg_buffer_id = 0;

/**
 * \brief Registration function for keyword: http_stat_msg
 */
void DetectHttpStatMsgRegister (void)
{
    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].name = "http_stat_msg";
    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].desc = "content modifier to match on HTTP stat-msg-buffer";
    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].url = DOC_URL DOC_VERSION "/rules/http-keywords.html#http_stat-msg";
    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].Match = NULL;
    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].Setup = DetectHttpStatMsgSetup;
    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].Free  = NULL;
    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].RegisterTests = DetectHttpStatMsgRegisterTests;

    sigmatch_table[DETECT_AL_HTTP_STAT_MSG].flags |= SIGMATCH_NOOPT;

    DetectAppLayerMpmRegister("http_stat_msg", SIG_FLAG_TOCLIENT, 3,
            PrefilterTxHttpStatMsgRegister);

    DetectAppLayerInspectEngineRegister("http_stat_msg",
            ALPROTO_HTTP, SIG_FLAG_TOCLIENT, HTP_RESPONSE_LINE,
            DetectEngineInspectHttpStatMsg);

    DetectBufferTypeSetDescriptionByName("http_stat_msg",
            "http response status message");

    DetectBufferTypeRegisterSetupCallback("http_stat_msg",
            DetectHttpStatMsgSetupCallback);

    g_http_stat_msg_buffer_id = DetectBufferTypeGetByName("http_stat_msg");
}

/**
 * \brief this function setups the http_stat_msg modifier keyword used in the rule
 *
 * \param de_ctx   Pointer to the Detection Engine Context
 * \param s        Pointer to the Signature to which the current keyword belongs
 * \param str      Should hold an empty string always
 *
 * \retval  0 On success
 * \retval -1 On failure
 */

static int DetectHttpStatMsgSetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
{
    return DetectEngineContentModifierBufferSetup(de_ctx, s, arg,
                                                  DETECT_AL_HTTP_STAT_MSG,
                                                  g_http_stat_msg_buffer_id,
                                                  ALPROTO_HTTP);
}

static void DetectHttpStatMsgSetupCallback(Signature *s)
{
    SCLogDebug("callback invoked by %u", s->id);
    s->mask |= SIG_MASK_REQUIRE_HTTP_STATE;
}

#ifdef UNITTESTS

/**
 * \test Checks if a http_stat_msg is registered in a Signature, if content is not
 *       specified in the signature or rawbyes is specified or fast_pattern is
 *       provided in the signature.
 */
static int DetectHttpStatMsgTest01(void)
{
    DetectEngineCtx *de_ctx = NULL;
    int result = 0;

    if ( (de_ctx = DetectEngineCtxInit()) == NULL)
        goto end;

    de_ctx->flags |= DE_QUIET;
    de_ctx->sig_list = SigInit(de_ctx, "alert tcp any any -> any any "
                               "(msg:\"Testing http_stat_msg\"; http_stat_msg;sid:1;)");
    if (de_ctx->sig_list != NULL)
        goto end;

    de_ctx->sig_list = SigInit(de_ctx, "alert tcp any any -> any any "
                               "(msg:\"Testing http_stat_msg\"; content:\"|FF F1|\";"
                                " rawbytes; http_stat_msg;sid:1;)");
    if (de_ctx->sig_list != NULL)
        goto end;

    de_ctx->sig_list = SigInit(de_ctx, "alert tcp any any -> any any "
                               "(msg:\"Testing http_stat_msg\"; content:\"one\";"
            "fast_pattern; http_stat_msg; sid:1;)");
    if (de_ctx->sig_list == NULL)
        goto end;
    if (!(((DetectContentData *)de_ctx->sig_list->sm_lists[g_http_stat_msg_buffer_id]->ctx)->flags &
        DETECT_CONTENT_FAST_PATTERN))
    {
        goto end;
    }

    result = 1;
end:
    if (de_ctx != NULL)
        DetectEngineCtxFree(de_ctx);
    return result;
}

/**
 * \test Checks if a http_stat_msg is registered in a Signature and also checks
 *       the nocase
 */
static int DetectHttpStatMsgTest02(void)
{
    SigMatch *sm = NULL;
    DetectEngineCtx *de_ctx = NULL;
    int result = 0;

    if ( (de_ctx = DetectEngineCtxInit()) == NULL)
        goto end;

    de_ctx->flags |= DE_QUIET;
    de_ctx->sig_list = SigInit(de_ctx, "alert tcp any any -> any any "
                               "(msg:\"Testing http_stat_msg\"; content:\"one\"; "
                               "http_stat_msg; content:\"two\"; http_stat_msg; "
                               "content:\"two\"; nocase; http_stat_msg; "
                               "sid:1;)");
    if (de_ctx->sig_list == NULL) {
        printf("sig parse failed: ");
        goto end;
    }

    result = 0;
    sm = de_ctx->sig_list->sm_lists[g_http_stat_msg_buffer_id];
    if (sm == NULL) {
        printf("no sigmatch(es): ");
        goto end;
    }

    SigMatch *prev = NULL;
    while (sm != NULL) {
        if (sm->type == DETECT_CONTENT) {
            result = 1;
        } else {
            printf("expected DETECT_CONTENT for http_stat_msg, got %d: ", sm->type);
            goto end;
        }
        prev = sm;
        sm = sm->next;
    }

    if (! (((DetectContentData *)prev->ctx)->flags &
            DETECT_CONTENT_NOCASE))
    {
        result = 0;
    }
end:
    if (de_ctx != NULL)
        DetectEngineCtxFree(de_ctx);
    return result;
}

/** \test Check the signature working to alert when http_stat_msg is matched . */
static int DetectHttpStatMsgSigTest01(void)
{
    int result = 0;
    Flow f;
    uint8_t httpbuf1[] = "POST / HTTP/1.0\r\nUser-Agent: Mozilla/1.0\r\n\r\n";
    uint32_t httplen1 = sizeof(httpbuf1) - 1; /* minus the \0 */
    uint8_t httpbuf2[] = "HTTP/1.0 200 OK\r\n\r\n";
    uint32_t httplen2 = sizeof(httpbuf2) - 1; /* minus the \0 */
    TcpSession ssn;
    Packet *p = NULL;
    Signature *s = NULL;
    ThreadVars th_v;
    DetectEngineThreadCtx *det_ctx = NULL;
    HtpState *http_state = NULL;
    AppLayerParserThreadCtx *alp_tctx = AppLayerParserThreadCtxAlloc();

    memset(&th_v, 0, sizeof(th_v));
    memset(&f, 0, sizeof(f));
    memset(&ssn, 0, sizeof(ssn));

    p = UTHBuildPacket(NULL, 0, IPPROTO_TCP);

    FLOW_INITIALIZE(&f);
    f.protoctx = (void *)&ssn;
    f.proto = IPPROTO_TCP;
    f.flags |= FLOW_IPV4;

    p->flow = &f;
    p->flowflags |= FLOW_PKT_TOCLIENT;
    p->flowflags |= FLOW_PKT_ESTABLISHED;
    p->flags |= PKT_HAS_FLOW|PKT_STREAM_EST;
    f.alproto = ALPROTO_HTTP;

    StreamTcpInitConfig(TRUE);

    DetectEngineCtx *de_ctx = DetectEngineCtxInit();
    if (de_ctx == NULL) {
        goto end;
    }

    de_ctx->flags |= DE_QUIET;

    s = de_ctx->sig_list = SigInit(de_ctx,"alert http any any -> any any (msg:"
                                   "\"HTTP status message\"; content:\"OK\"; "
                                   "http_stat_msg; sid:1;)");
    if (s == NULL) {
        goto end;
    }

    s->next = SigInit(de_ctx,"alert http any any -> any any (msg:\"HTTP "
                      "Status message nocase\"; content:\"ok\"; nocase; "
                      "http_stat_msg; sid:2;)");
    if (s->next == NULL) {
        goto end;
    }

    SigGroupBuild(de_ctx);
    DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx);

    FLOWLOCK_WRLOCK(&f);
    int r = AppLayerParserParse(NULL, alp_tctx, &f, ALPROTO_HTTP,
                                STREAM_TOSERVER, httpbuf1, httplen1);
    if (r != 0) {
        printf("toserver chunk 1 returned %" PRId32 ", expected 0: ", r);
        result = 0;
        FLOWLOCK_UNLOCK(&f);
        goto end;
    }

    r = AppLayerParserParse(NULL, alp_tctx, &f, ALPROTO_HTTP,
                            STREAM_TOCLIENT, httpbuf2, httplen2);
    if (r != 0) {
        printf("toclient chunk 1 returned %" PRId32 ", expected 0: ", r);
        result = 0;
        FLOWLOCK_UNLOCK(&f);
        goto end;
    }
    FLOWLOCK_UNLOCK(&f);

    http_state = f.alstate;
    if (http_state == NULL) {
        printf("no http state: ");
        result = 0;
        goto end;
    }

    /* do detect */
    SigMatchSignatures(&th_v, de_ctx, det_ctx, p);

    if (!(PacketAlertCheck(p, 1))) {
        printf("sid 1 didn't match but should have: ");
        goto end;
    }
    if (!(PacketAlertCheck(p, 2))) {
        printf("sid 2 didn't match but should have: ");
        goto end;
    }

    result = 1;
end:
    if (alp_tctx != NULL)
        AppLayerParserThreadCtxFree(alp_tctx);
    if (det_ctx != NULL) {
        DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
    }
    if (de_ctx != NULL) {
        SigGroupCleanup(de_ctx);
        DetectEngineCtxFree(de_ctx);
    }

    StreamTcpFreeConfig(TRUE);

    UTHFreePackets(&p, 1);
    return result;
}

/** \test Check the signature working to alert when http_stat_msg is not matched . */
static int DetectHttpStatMsgSigTest02(void)
{
    int result = 0;
    Flow f;
    uint8_t httpbuf1[] = "POST / HTTP/1.0\r\nUser-Agent: Mozilla/1.0\r\n\r\n";
    uint32_t httplen1 = sizeof(httpbuf1) - 1; /* minus the \0 */
    uint8_t httpbuf2[] = "HTTP/1.0 200 OK\r\n\r\n";
    uint32_t httplen2 = sizeof(httpbuf2) - 1; /* minus the \0 */
    TcpSession ssn;
    Packet *p = NULL;
    Signature *s = NULL;
    ThreadVars th_v;
    DetectEngineThreadCtx *det_ctx = NULL;
    HtpState *http_state = NULL;
    AppLayerParserThreadCtx *alp_tctx = AppLayerParserThreadCtxAlloc();

    memset(&th_v, 0, sizeof(th_v));
    memset(&f, 0, sizeof(f));
    memset(&ssn, 0, sizeof(ssn));

    p = UTHBuildPacket(NULL, 0, IPPROTO_TCP);

    FLOW_INITIALIZE(&f);
    f.protoctx = (void *)&ssn;
    f.proto = IPPROTO_TCP;
    f.flags |= FLOW_IPV4;

    p->flow = &f;
    p->flowflags |= FLOW_PKT_TOCLIENT;
    p->flowflags |= FLOW_PKT_ESTABLISHED;
    p->flags |= PKT_HAS_FLOW|PKT_STREAM_EST;
    f.alproto = ALPROTO_HTTP;

    StreamTcpInitConfig(TRUE);

    DetectEngineCtx *de_ctx = DetectEngineCtxInit();
    if (de_ctx == NULL) {
        goto end;
    }

    de_ctx->flags |= DE_QUIET;

    s = de_ctx->sig_list = SigInit(de_ctx,"alert http any any -> any any (msg:"
                                   "\"HTTP status message\"; content:\"no\"; "
                                   "http_stat_msg; sid:1;)");
    if (s == NULL) {
        goto end;
    }

    SigGroupBuild(de_ctx);
    DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx);

    FLOWLOCK_WRLOCK(&f);
    int r = AppLayerParserParse(NULL, alp_tctx, &f, ALPROTO_HTTP,
                                STREAM_TOSERVER, httpbuf1, httplen1);
    if (r != 0) {
        printf("toserver chunk 1 returned %" PRId32 ", expected 0: ", r);
        result = 0;
        FLOWLOCK_UNLOCK(&f);
        goto end;
    }

    r = AppLayerParserParse(NULL, alp_tctx, &f, ALPROTO_HTTP,
                            STREAM_TOCLIENT, httpbuf2, httplen2);
    if (r != 0) {
        printf("toclient chunk 1 returned %" PRId32 ", expected 0: ", r);
        result = 0;
        FLOWLOCK_UNLOCK(&f);
        goto end;
    }
    FLOWLOCK_UNLOCK(&f);

    http_state = f.alstate;
    if (http_state == NULL) {
        printf("no http state: ");
        result = 0;
        goto end;
    }

    /* do detect */
    SigMatchSignatures(&th_v, de_ctx, det_ctx, p);

    if (PacketAlertCheck(p, 1)) {
        printf("sid 1 matched but shouldn't: ");
        goto end;
    }

    result = 1;
end:
    if (alp_tctx != NULL)
        AppLayerParserThreadCtxFree(alp_tctx);
    if (det_ctx != NULL) {
        DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
    }
    if (de_ctx != NULL) {
        SigGroupCleanup(de_ctx);
        DetectEngineCtxFree(de_ctx);
    }

    StreamTcpFreeConfig(TRUE);

    UTHFreePackets(&p, 1);
    return result;
}

/** \test Check the signature working to alert when http_stat_msg is used with
 *        negated content . */
static int DetectHttpStatMsgSigTest03(void)
{
    int result = 0;
    Flow f;
    uint8_t httpbuf1[] = "POST / HTTP/1.0\r\nUser-Agent: Mozilla/1.0\r\n\r\n";
    uint32_t httplen1 = sizeof(httpbuf1) - 1; /* minus the \0 */
    uint8_t httpbuf2[] = "HTTP/1.0 200 OK\r\n\r\n";
    uint32_t httplen2 = sizeof(httpbuf2) - 1; /* minus the \0 */
    TcpSession ssn;
    Packet *p = NULL;
    Signature *s = NULL;
    ThreadVars th_v;
    DetectEngineThreadCtx *det_ctx = NULL;
    HtpState *http_state = NULL;
    AppLayerParserThreadCtx *alp_tctx = AppLayerParserThreadCtxAlloc();

    memset(&th_v, 0, sizeof(th_v));
    memset(&f, 0, sizeof(f));
    memset(&ssn, 0, sizeof(ssn));

    p = UTHBuildPacket(NULL, 0, IPPROTO_TCP);

    FLOW_INITIALIZE(&f);
    f.protoctx = (void *)&ssn;
    f.proto = IPPROTO_TCP;
    f.flags |= FLOW_IPV4;

    p->flow = &f;
    p->flowflags |= FLOW_PKT_TOCLIENT;
    p->flowflags |= FLOW_PKT_ESTABLISHED;
    p->flags |= PKT_HAS_FLOW|PKT_STREAM_EST;
    f.alproto = ALPROTO_HTTP;

    StreamTcpInitConfig(TRUE);

    DetectEngineCtx *de_ctx = DetectEngineCtxInit();
    if (de_ctx == NULL) {
        goto end;
    }

    de_ctx->flags |= DE_QUIET;

    s = de_ctx->sig_list = SigInit(de_ctx,"alert http any any -> any any (msg:"
                                   "\"HTTP status message\"; content:\"ok\"; "
                                   "nocase; http_stat_msg; sid:1;)");
    if (s == NULL) {
        goto end;
    }

    s->next = SigInit(de_ctx,"alert http any any -> any any (msg:\"HTTP "
                        "Status message nocase\"; content:!\"Not\"; "
                        "http_stat_msg; sid:2;)");
    if (s->next == NULL) {
        goto end;
    }

    SigGroupBuild(de_ctx);
    DetectEngineThreadCtxInit(&th_v, (void *)de_ctx, (void *)&det_ctx);

    FLOWLOCK_WRLOCK(&f);
    int r = AppLayerParserParse(NULL, alp_tctx, &f, ALPROTO_HTTP,
                                STREAM_TOSERVER, httpbuf1, httplen1);
    if (r != 0) {
        printf("toserver chunk 1 returned %" PRId32 ", expected 0: ", r);
        result = 0;
        FLOWLOCK_UNLOCK(&f);
        goto end;
    }

    r = AppLayerParserParse(NULL, alp_tctx, &f, ALPROTO_HTTP,
                            STREAM_TOCLIENT, httpbuf2, httplen2);
    if (r != 0) {
        printf("toclient chunk 1 returned %" PRId32 ", expected 0: ", r);
        result = 0;
        FLOWLOCK_UNLOCK(&f);
        goto end;
    }
    FLOWLOCK_UNLOCK(&f);

    http_state = f.alstate;
    if (http_state == NULL) {
        printf("no http state: ");
        result = 0;
        goto end;
    }

    /* do detect */
    SigMatchSignatures(&th_v, de_ctx, det_ctx, p);

    if (! PacketAlertCheck(p, 1)) {
        printf("sid 1 didn't matched but should have: ");
        goto end;
    }
    if (! PacketAlertCheck(p, 2)) {
        printf("sid 2 didn't matched but should have: ");
        goto end;
    }

    result = 1;
end:
    if (alp_tctx != NULL)
        AppLayerParserThreadCtxFree(alp_tctx);
    if (det_ctx != NULL) {
        DetectEngineThreadCtxDeinit(&th_v, (void *)det_ctx);
    }
    if (de_ctx != NULL) {
        SigGroupCleanup(de_ctx);
        DetectEngineCtxFree(de_ctx);
    }

    StreamTcpFreeConfig(TRUE);

    UTHFreePackets(&p, 1);
    return result;
}

#endif /* UNITTESTS */

/**
 * \brief   Register the UNITTESTS for the http_stat_msg keyword
 */
void DetectHttpStatMsgRegisterTests (void)
{
#ifdef UNITTESTS /* UNITTESTS */

    UtRegisterTest("DetectHttpStatMsgTest01", DetectHttpStatMsgTest01);
    UtRegisterTest("DetectHttpStatMsgTest02", DetectHttpStatMsgTest02);
    UtRegisterTest("DetectHttpStatMsgSigTest01", DetectHttpStatMsgSigTest01);
    UtRegisterTest("DetectHttpStatMsgSigTest02", DetectHttpStatMsgSigTest02);
    UtRegisterTest("DetectHttpStatMsgSigTest03", DetectHttpStatMsgSigTest03);

#endif /* UNITTESTS */
}
/**
 * @}
 */