diff --git a/doc/userguide/rules/kerberos-keywords.rst b/doc/userguide/rules/kerberos-keywords.rst index 5b19715d5f..91f4f97e38 100644 --- a/doc/userguide/rules/kerberos-keywords.rst +++ b/doc/userguide/rules/kerberos-keywords.rst @@ -68,3 +68,18 @@ Signature example:: ``krb5_sname`` is a 'sticky buffer'. ``krb5_sname`` can be used as ``fast_pattern``. + +krb5_err_code +------------- + +Kerberos error code (integer). This field is matched in Kerberos error messages only. + +For a list of error codes, refer to RFC4120 section 7.5.9. + +Syntax:: + + krb5_err_code: + +Signature example:: + + alert krb5 any any -> any any (msg:"Kerberos 5 error C_PRINCIPAL_UNKNOWN"; krb5_err_code:6; sid:6; rev:1;) diff --git a/rust/gen-c-headers.py b/rust/gen-c-headers.py index aa7d59d1c2..1c103ae975 100755 --- a/rust/gen-c-headers.py +++ b/rust/gen-c-headers.py @@ -63,6 +63,7 @@ type_map = { "libc::c_int": "int", "c_int": "int", "libc::int8_t": "int8_t", + "libc::int32_t": "int32_t", "libc::uint8_t": "uint8_t", "libc::uint16_t": "uint16_t", diff --git a/rust/src/krb/detect.rs b/rust/src/krb/detect.rs index f32180e243..d05da4725a 100644 --- a/rust/src/krb/detect.rs +++ b/rust/src/krb/detect.rs @@ -28,6 +28,21 @@ pub unsafe extern "C" fn rs_krb5_tx_get_msgtype(tx: &mut KRB5Transaction, *ptr = tx.msg_type.0; } +/// Get error code, if present in transaction +/// Return 0 if error code was filled, else 1 +#[no_mangle] +pub unsafe extern "C" fn rs_krb5_tx_get_errcode(tx: &mut KRB5Transaction, + ptr: *mut libc::int32_t) -> u32 +{ + match tx.error_code { + Some(ref e) => { + *ptr = e.0; + 0 + }, + None => 1 + } +} + #[no_mangle] pub unsafe extern "C" fn rs_krb5_tx_get_cname(tx: &mut KRB5Transaction, i: libc::uint16_t, diff --git a/src/Makefile.am b/src/Makefile.am index d7626b4f71..f16246502d 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -214,6 +214,7 @@ detect-iprep.c detect-iprep.h \ detect-isdataat.c detect-isdataat.h \ detect-itype.c detect-itype.h \ detect-krb5-cname.c detect-krb5-cname.h \ +detect-krb5-errcode.c detect-krb5-errcode.h \ detect-krb5-msgtype.c detect-krb5-msgtype.h \ detect-krb5-sname.c detect-krb5-sname.h \ detect-l3proto.c detect-l3proto.h \ diff --git a/src/detect-engine-register.c b/src/detect-engine-register.c index 2808f1e326..dec1c4c73e 100644 --- a/src/detect-engine-register.c +++ b/src/detect-engine-register.c @@ -179,6 +179,7 @@ #include "detect-app-layer-protocol.h" #include "detect-template.h" #include "detect-krb5-cname.h" +#include "detect-krb5-errcode.h" #include "detect-krb5-msgtype.h" #include "detect-krb5-sname.h" #include "detect-target.h" @@ -494,6 +495,7 @@ void SigTableSetup(void) DetectBase64DataRegister(); DetectTemplateRegister(); DetectKrb5CNameRegister(); + DetectKrb5ErrCodeRegister(); DetectKrb5MsgTypeRegister(); DetectKrb5SNameRegister(); DetectTargetRegister(); diff --git a/src/detect-engine-register.h b/src/detect-engine-register.h index b01f08380a..79c8b9ac0b 100644 --- a/src/detect-engine-register.h +++ b/src/detect-engine-register.h @@ -197,6 +197,7 @@ enum { DETECT_BASE64_DECODE, DETECT_BASE64_DATA, + DETECT_AL_KRB5_ERRCODE, DETECT_AL_KRB5_MSGTYPE, DETECT_AL_KRB5_CNAME, DETECT_AL_KRB5_SNAME, diff --git a/src/detect-krb5-errcode.c b/src/detect-krb5-errcode.c new file mode 100644 index 0000000000..57e46a5ad3 --- /dev/null +++ b/src/detect-krb5-errcode.c @@ -0,0 +1,275 @@ +/* Copyright (C) 2018 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 Pierre Chifflier + */ + +#include "suricata-common.h" +#include "util-unittest.h" + +#include "detect-parse.h" +#include "detect-engine.h" + +#include "detect-krb5-errcode.h" + +#ifdef HAVE_RUST + +#include "app-layer-krb5.h" +#include "rust-krb-detect-gen.h" + +/** + * \brief Regex for parsing our keyword options + */ +#define PARSE_REGEX "^\\s*([A-z0-9\\.]+|\"[A-z0-9_\\.]+\")\\s*$" +static pcre *parse_regex; +static pcre_extra *parse_regex_study; + +/* Prototypes of functions registered in DetectKrb5ErrCodeRegister below */ +static int DetectKrb5ErrCodeMatch (ThreadVars *, DetectEngineThreadCtx *, Flow *, + uint8_t, void *, void *, const Signature *, + const SigMatchCtx *); +static int DetectKrb5ErrCodeSetup (DetectEngineCtx *, Signature *, const char *); +static void DetectKrb5ErrCodeFree (void *); +static void DetectKrb5ErrCodeRegisterTests (void); + +static int DetectEngineInspectKRB5Generic(ThreadVars *tv, + DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, + const Signature *s, const SigMatchData *smd, + Flow *f, uint8_t flags, void *alstate, + void *txv, uint64_t tx_id); + +static int g_krb5_err_code_list_id = 0; + +/** + * \brief Registration function for krb5_err_code: keyword + * + * This function is called once in the 'lifetime' of the engine. + */ +void DetectKrb5ErrCodeRegister(void) { + sigmatch_table[DETECT_AL_KRB5_ERRCODE].name = "krb5_err_code"; + sigmatch_table[DETECT_AL_KRB5_ERRCODE].desc = "match Kerberos 5 message type"; + sigmatch_table[DETECT_AL_KRB5_ERRCODE].url = DOC_URL DOC_VERSION "/rules/kerberos-keywords.html#krb5_err_code"; + sigmatch_table[DETECT_AL_KRB5_ERRCODE].Match = NULL; + sigmatch_table[DETECT_AL_KRB5_ERRCODE].AppLayerTxMatch = DetectKrb5ErrCodeMatch; + sigmatch_table[DETECT_AL_KRB5_ERRCODE].Setup = DetectKrb5ErrCodeSetup; + sigmatch_table[DETECT_AL_KRB5_ERRCODE].Free = DetectKrb5ErrCodeFree; + sigmatch_table[DETECT_AL_KRB5_ERRCODE].RegisterTests = DetectKrb5ErrCodeRegisterTests; + + DetectAppLayerInspectEngineRegister("krb5_err_code", + ALPROTO_KRB5, SIG_FLAG_TOSERVER, 0, + DetectEngineInspectKRB5Generic); + + DetectAppLayerInspectEngineRegister("krb5_err_code", + ALPROTO_KRB5, SIG_FLAG_TOCLIENT, 0, + DetectEngineInspectKRB5Generic); + + /* set up the PCRE for keyword parsing */ + DetectSetupParseRegexes(PARSE_REGEX, &parse_regex, &parse_regex_study); + + g_krb5_err_code_list_id = DetectBufferTypeRegister("krb5_err_code"); + SCLogDebug("g_krb5_err_code_list_id %d", g_krb5_err_code_list_id); +} + +static int DetectEngineInspectKRB5Generic(ThreadVars *tv, + DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx, + const Signature *s, const SigMatchData *smd, + Flow *f, uint8_t flags, void *alstate, + void *txv, uint64_t tx_id) +{ + return DetectEngineInspectGenericList(tv, de_ctx, det_ctx, s, smd, + f, flags, alstate, txv, tx_id); +} + +/** + * \brief This function is used to match KRB5 rule option on a packet + * + * \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 with context that we will cast into DetectKrb5Data + * + * \retval 0 no match + * \retval 1 match + */ +static int DetectKrb5ErrCodeMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, + Flow *f, uint8_t flags, void *state, + void *txv, const Signature *s, + const SigMatchCtx *ctx) +{ + int32_t err_code; + int ret; + const DetectKrb5ErrCodeData *dd = (const DetectKrb5ErrCodeData *)ctx; + + SCEnter(); + + ret = rs_krb5_tx_get_errcode(txv, &err_code); + if (ret != 0) + SCReturnInt(0); + + if (dd->err_code == err_code) + SCReturnInt(1); + + SCReturnInt(0); +} + +/** + * \brief This function is used to parse options passed via krb5_errcode: keyword + * + * \param krb5str Pointer to the user provided krb5_err_code options + * + * \retval krb5d pointer to DetectKrb5Data on success + * \retval NULL on failure + */ +static DetectKrb5ErrCodeData *DetectKrb5ErrCodeParse (const char *krb5str) +{ + DetectKrb5ErrCodeData *krb5d = NULL; + char arg1[4] = ""; +#define MAX_SUBSTRINGS 30 + int ret = 0, res = 0; + int ov[MAX_SUBSTRINGS]; + + ret = pcre_exec(parse_regex, parse_regex_study, + krb5str, strlen(krb5str), + 0, 0, ov, MAX_SUBSTRINGS); + if (ret != 2) { + SCLogError(SC_ERR_PCRE_MATCH, "parse error, ret %" PRId32 "", ret); + goto error; + } + + res = pcre_copy_substring((char *) krb5str, ov, MAX_SUBSTRINGS, 1, arg1, sizeof(arg1)); + if (res < 0) { + SCLogError(SC_ERR_PCRE_GET_SUBSTRING, "pcre_copy_substring failed"); + goto error; + } + + krb5d = SCMalloc(sizeof (DetectKrb5ErrCodeData)); + if (unlikely(krb5d == NULL)) + goto error; + krb5d->err_code = (int32_t)atoi(arg1); + + return krb5d; + +error: + if (krb5d) + SCFree(krb5d); + return NULL; +} + +/** + * \brief parse the options from the 'krb5_err_code' keyword in the rule into + * the Signature data structure. + * + * \param de_ctx pointer to the Detection Engine Context + * \param s pointer to the Current Signature + * \param krb5str pointer to the user provided options + * + * \retval 0 on Success + * \retval -1 on Failure + */ +static int DetectKrb5ErrCodeSetup (DetectEngineCtx *de_ctx, Signature *s, const char *krb5str) +{ + DetectKrb5ErrCodeData *krb5d = NULL; + SigMatch *sm = NULL; + + if (DetectSignatureSetAppProto(s, ALPROTO_KRB5) != 0) + return -1; + + krb5d = DetectKrb5ErrCodeParse(krb5str); + if (krb5d == NULL) + goto error; + + sm = SigMatchAlloc(); + if (sm == NULL) + goto error; + + sm->type = DETECT_AL_KRB5_ERRCODE; + sm->ctx = (void *)krb5d; + + s->flags |= SIG_FLAG_STATE_MATCH; + SigMatchAppendSMToList(s, sm, g_krb5_err_code_list_id); + + return 0; + +error: + if (krb5d != NULL) + DetectKrb5ErrCodeFree(krb5d); + if (sm != NULL) + SCFree(sm); + return -1; +} + +/** + * \brief this function will free memory associated with DetectKrb5Data + * + * \param ptr pointer to DetectKrb5Data + */ +static void DetectKrb5ErrCodeFree(void *ptr) { + DetectKrb5ErrCodeData *krb5d = (DetectKrb5ErrCodeData *)ptr; + + SCFree(krb5d); +} + +#ifdef UNITTESTS + +/** + * \test description of the test + */ + +static int DetectKrb5ErrCodeParseTest01 (void) +{ + DetectKrb5ErrCodeData *krb5d = DetectKrb5ErrCodeParse("10"); + FAIL_IF_NULL(krb5d); + FAIL_IF(!(krb5d->err_code == 10)); + DetectKrb5ErrCodeFree(krb5d); + PASS; +} + +static int DetectKrb5ErrCodeSignatureTest01 (void) +{ + DetectEngineCtx *de_ctx = DetectEngineCtxInit(); + FAIL_IF_NULL(de_ctx); + + Signature *sig = DetectEngineAppendSig(de_ctx, "alert krb5 any any -> any any (krb5_err_code:10; sid:1; rev:1;)"); + FAIL_IF_NULL(sig); + + DetectEngineCtxFree(de_ctx); + PASS; +} + +#endif /* UNITTESTS */ + +/** + * \brief this function registers unit tests for DetectKrb5ErrCode + */ +static void DetectKrb5ErrCodeRegisterTests(void) { +#ifdef UNITTESTS + UtRegisterTest("DetectKrb5ErrCodeParseTest01", DetectKrb5ErrCodeParseTest01); + UtRegisterTest("DetectKrb5ErrCodeSignatureTest01", + DetectKrb5ErrCodeSignatureTest01); +#endif /* UNITTESTS */ +} + +#else /* HAVE_RUST */ + +void DetectKrb5ErrCodeRegister(void) +{ +} + +#endif /* HAVE_RUST */ diff --git a/src/detect-krb5-errcode.h b/src/detect-krb5-errcode.h new file mode 100644 index 0000000000..b803e9fb56 --- /dev/null +++ b/src/detect-krb5-errcode.h @@ -0,0 +1,33 @@ +/* Copyright (C) 2015-2017 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 Pierre Chifflier + */ + +#ifndef __DETECT_KRB5_ERRCODE_H__ +#define __DETECT_KRB5_ERRCODE_H__ + +typedef struct DetectKrb5ErrCodeData_ { + int32_t err_code; +} DetectKrb5ErrCodeData; + +void DetectKrb5ErrCodeRegister(void); + +#endif /* __DETECT_KRB5_ERRCODE_H__ */