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Diffstat (limited to '')
| -rw-r--r-- | src/detect-ssl-version.c | 335 |
1 files changed, 335 insertions, 0 deletions
diff --git a/src/detect-ssl-version.c b/src/detect-ssl-version.c new file mode 100644 index 0000000..b4e142b --- /dev/null +++ b/src/detect-ssl-version.c @@ -0,0 +1,335 @@ +/* Copyright (C) 2007-2020 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 detect-ssl-version.c + * + * \author Gurvinder Singh <gurvindersinghdahiya@gmail.com> + * + * Implements the ssl_version keyword + */ + +#include "suricata-common.h" +#include "threads.h" +#include "decode.h" + +#include "detect.h" +#include "detect-parse.h" + +#include "detect-engine.h" +#include "detect-engine-mpm.h" +#include "detect-engine-state.h" + +#include "flow.h" +#include "flow-var.h" +#include "flow-util.h" + +#include "util-debug.h" +#include "util-unittest.h" +#include "util-unittest-helper.h" + +#include "app-layer.h" +#include "app-layer-parser.h" + +#include "detect-ssl-version.h" + +#include "stream-tcp.h" +#include "app-layer-ssl.h" + + +static int DetectSslVersionMatch(DetectEngineThreadCtx *, + Flow *, uint8_t, void *, void *, + const Signature *, const SigMatchCtx *); +static int DetectSslVersionSetup(DetectEngineCtx *, Signature *, const char *); +#ifdef UNITTESTS +static void DetectSslVersionRegisterTests(void); +#endif +static void DetectSslVersionFree(DetectEngineCtx *, void *); +static int g_tls_generic_list_id = 0; + +/** + * \brief Registration function for keyword: ssl_version + */ +void DetectSslVersionRegister(void) +{ + sigmatch_table[DETECT_AL_SSL_VERSION].name = "ssl_version"; + sigmatch_table[DETECT_AL_SSL_VERSION].desc = "match version of SSL/TLS record"; + sigmatch_table[DETECT_AL_SSL_VERSION].url = "/rules/tls-keywords.html#ssl-version"; + sigmatch_table[DETECT_AL_SSL_VERSION].AppLayerTxMatch = DetectSslVersionMatch; + sigmatch_table[DETECT_AL_SSL_VERSION].Setup = DetectSslVersionSetup; + sigmatch_table[DETECT_AL_SSL_VERSION].Free = DetectSslVersionFree; +#ifdef UNITTESTS + sigmatch_table[DETECT_AL_SSL_VERSION].RegisterTests = DetectSslVersionRegisterTests; +#endif + + g_tls_generic_list_id = DetectBufferTypeRegister("tls_generic"); +} + +/** + * \brief match the specified version on a ssl session + * + * \param t pointer to thread vars + * \param det_ctx pointer to the pattern matcher thread + * \param p pointer to the current packet + * \param m pointer to the sigmatch that we will cast into DetectSslVersionData + * + * \retval 0 no match + * \retval 1 match + */ +static int DetectSslVersionMatch(DetectEngineThreadCtx *det_ctx, + Flow *f, uint8_t flags, void *state, void *txv, + const Signature *s, const SigMatchCtx *m) +{ + SCEnter(); + + int ret = 0; + uint16_t ver = 0; + uint8_t sig_ver = TLS_UNKNOWN; + + const DetectSslVersionData *ssl = (const DetectSslVersionData *)m; + SSLState *app_state = (SSLState *)state; + if (app_state == NULL) { + SCLogDebug("no app state, no match"); + SCReturnInt(0); + } + + if (flags & STREAM_TOCLIENT) { + SCLogDebug("server (toclient) version is 0x%02X", + app_state->server_connp.version); + ver = app_state->server_connp.version; + } else if (flags & STREAM_TOSERVER) { + SCLogDebug("client (toserver) version is 0x%02X", + app_state->client_connp.version); + ver = app_state->client_connp.version; + } + + switch (ver) { + case SSL_VERSION_2: + if (ver == ssl->data[SSLv2].ver) + ret = 1; + sig_ver = SSLv2; + break; + case SSL_VERSION_3: + if (ver == ssl->data[SSLv3].ver) + ret = 1; + sig_ver = SSLv3; + break; + case TLS_VERSION_10: + if (ver == ssl->data[TLS10].ver) + ret = 1; + sig_ver = TLS10; + break; + case TLS_VERSION_11: + if (ver == ssl->data[TLS11].ver) + ret = 1; + sig_ver = TLS11; + break; + case TLS_VERSION_12: + if (ver == ssl->data[TLS12].ver) + ret = 1; + sig_ver = TLS12; + break; + case TLS_VERSION_13_DRAFT28: + case TLS_VERSION_13_DRAFT27: + case TLS_VERSION_13_DRAFT26: + case TLS_VERSION_13_DRAFT25: + case TLS_VERSION_13_DRAFT24: + case TLS_VERSION_13_DRAFT23: + case TLS_VERSION_13_DRAFT22: + case TLS_VERSION_13_DRAFT21: + case TLS_VERSION_13_DRAFT20: + case TLS_VERSION_13_DRAFT19: + case TLS_VERSION_13_DRAFT18: + case TLS_VERSION_13_DRAFT17: + case TLS_VERSION_13_DRAFT16: + case TLS_VERSION_13_PRE_DRAFT16: + if (((ver >> 8) & 0xff) == 0x7f) + ver = TLS_VERSION_13; + /* fall through */ + case TLS_VERSION_13: + if (ver == ssl->data[TLS13].ver) + ret = 1; + sig_ver = TLS13; + break; + } + + if (sig_ver == TLS_UNKNOWN) + SCReturnInt(0); + + SCReturnInt(ret ^ ((ssl->data[sig_ver].flags & DETECT_SSL_VERSION_NEGATED) ? 1 : 0)); +} + +struct SSLVersionKeywords { + const char *word; + int index; + uint16_t value; +}; + +struct SSLVersionKeywords ssl_version_keywords[TLS_SIZE] = { + { "sslv2", SSLv2, SSL_VERSION_2 }, + { "sslv3", SSLv3, SSL_VERSION_3 }, + { "tls1.0", TLS10, TLS_VERSION_10 }, + { "tls1.1", TLS11, TLS_VERSION_11 }, + { "tls1.2", TLS12, TLS_VERSION_12 }, + { "tls1.3", TLS13, TLS_VERSION_13 }, +}; + +/** + * \brief This function is used to parse ssl_version data passed via + * keyword: "ssl_version" + * + * \param de_ctx Pointer to the detection engine context + * \param str Pointer to the user provided options + * + * \retval ssl pointer to DetectSslVersionData on success + * \retval NULL on failure + */ +static DetectSslVersionData *DetectSslVersionParse(DetectEngineCtx *de_ctx, const char *str) +{ + DetectSslVersionData *ssl = NULL; + const char *tmp_str = str; + size_t tmp_len = 0; + uint8_t found = 0; + + /* We have a correct ssl_version options */ + ssl = SCCalloc(1, sizeof(DetectSslVersionData)); + if (unlikely(ssl == NULL)) + goto error; + + // skip leading space + while (tmp_str[0] != 0 && isspace(tmp_str[0])) { + tmp_str++; + } + if (tmp_str[0] == 0) { + SCLogError("Invalid empty value"); + goto error; + } + // iterate every version separated by comma + while (tmp_str[0] != 0) { + uint8_t neg = 0; + if (tmp_str[0] == '!') { + neg = 1; + tmp_str++; + } + // counts word length + tmp_len = 0; + while (tmp_str[tmp_len] != 0 && !isspace(tmp_str[tmp_len]) && tmp_str[tmp_len] != ',') { + tmp_len++; + } + + bool is_keyword = false; + for (size_t i = 0; i < TLS_SIZE; i++) { + if (tmp_len == strlen(ssl_version_keywords[i].word) && + strncasecmp(ssl_version_keywords[i].word, tmp_str, tmp_len) == 0) { + if (ssl->data[ssl_version_keywords[i].index].ver != 0) { + SCLogError("Invalid duplicate value"); + goto error; + } + ssl->data[ssl_version_keywords[i].index].ver = ssl_version_keywords[i].value; + if (neg == 1) + ssl->data[ssl_version_keywords[i].index].flags |= DETECT_SSL_VERSION_NEGATED; + is_keyword = true; + break; + } + } + if (!is_keyword) { + SCLogError("Invalid unknown value"); + goto error; + } + + /* check consistency between negative and positive values : + * if there is a negative value, it overrides positive values + */ + if (found == 0) { + found |= 1 << neg; + } else if (found != 1 << neg) { + SCLogError("Invalid value mixing negative and positive forms"); + goto error; + } + + tmp_str += tmp_len; + while (isspace(tmp_str[0]) || tmp_str[0] == ',') { + tmp_str++; + } + } + + return ssl; + +error: + if (ssl != NULL) + DetectSslVersionFree(de_ctx, ssl); + return NULL; + +} + +/** + * \brief this function is used to add the parsed "id" option + * \brief into the current signature + * + * \param de_ctx pointer to the Detection Engine Context + * \param s pointer to the Current Signature + * \param idstr pointer to the user provided "id" option + * + * \retval 0 on Success + * \retval -1 on Failure + */ +static int DetectSslVersionSetup (DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + DetectSslVersionData *ssl = NULL; + SigMatch *sm = NULL; + + if (DetectSignatureSetAppProto(s, ALPROTO_TLS) != 0) + return -1; + + ssl = DetectSslVersionParse(de_ctx, str); + if (ssl == NULL) + goto error; + + /* Okay so far so good, lets get this into a SigMatch + * and put it in the Signature. */ + sm = SigMatchAlloc(); + if (sm == NULL) + goto error; + + sm->type = DETECT_AL_SSL_VERSION; + sm->ctx = (void *)ssl; + + SigMatchAppendSMToList(s, sm, g_tls_generic_list_id); + return 0; + +error: + if (ssl != NULL) + DetectSslVersionFree(de_ctx, ssl); + if (sm != NULL) + SCFree(sm); + return -1; +} + +/** + * \brief this function will free memory associated with DetectSslVersionData + * + * \param id_d pointer to DetectSslVersionData + */ +void DetectSslVersionFree(DetectEngineCtx *de_ctx, void *ptr) +{ + if (ptr != NULL) + SCFree(ptr); +} + +#ifdef UNITTESTS +#include "tests/detect-ssl-version.c" +#endif |