src/detect-ike-nonce-payload-length.c

   1 /* Copyright (C) 2020 Open Information Security Foundation
   2  *
   3  * You can copy, redistribute or modify this Program under the terms of
   4  * the GNU General Public License version 2 as published by the Free
   5  * Software Foundation.
   6  *
   7  * This program is distributed in the hope that it will be useful,
   8  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10  * GNU General Public License for more details.
  11  *
  12  * You should have received a copy of the GNU General Public License
  13  * version 2 along with this program; if not, write to the Free Software
  14  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  15  * 02110-1301, USA.
  16  */
  17
  18 /**
  19  *
  20  * \author Frank Honza <frank.honza@dcso.de>
  21  */
  22
  23 #include "suricata-common.h"
  24 #include "conf.h"
  25 #include "detect.h"
  26 #include "detect-parse.h"
  27 #include "detect-engine.h"
  28 #include "detect-engine-content-inspection.h"
  29 #include "detect-ike-nonce-payload-length.h"
  30 #include "app-layer-parser.h"
  31 #include "util-byte.h"
  32 #include "detect-engine-uint.h"
  33
  34 #include "rust-bindings.h"
  35
  36 /**
  37  *   [ike.nonce_payload_length]:[=|<|>|<=|>=]<length>;
  38  */
  39 static int DetectIkeNoncePayloadLengthSetup(DetectEngineCtx *, Signature *s, const char *str);
  40 static void DetectIkeNoncePayloadLengthFree(DetectEngineCtx *, void *);
  41 static int g_ike_nonce_payload_length_buffer_id = 0;
  42
  43 static int DetectEngineInspectIkeNoncePayloadLengthGeneric(DetectEngineCtx *de_ctx,
  44         DetectEngineThreadCtx *det_ctx, const struct DetectEngineAppInspectionEngine_ *engine,
  45         const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id);
  46
  47 static int DetectIkeNoncePayloadLengthMatch(DetectEngineThreadCtx *, Flow *, uint8_t, void *,
  48         void *, const Signature *, const SigMatchCtx *);
  49
  50 /**
  51  * \brief Registration function for ike.nonce_payload_length keyword.
  52  */
  53 void DetectIkeNoncePayloadLengthRegister(void)
  54 {
  55     sigmatch_table[DETECT_AL_IKE_NONCE_PAYLOAD_LENGTH].name = "ike.nonce_payload_length";
  56     sigmatch_table[DETECT_AL_IKE_NONCE_PAYLOAD_LENGTH].desc = "match IKE nonce payload length";
  57     sigmatch_table[DETECT_AL_IKE_NONCE_PAYLOAD_LENGTH].url =
  58             "/rules/ike-keywords.html#ike-nonce-payload-length";
  59     sigmatch_table[DETECT_AL_IKE_NONCE_PAYLOAD_LENGTH].AppLayerTxMatch =
  60             DetectIkeNoncePayloadLengthMatch;
  61     sigmatch_table[DETECT_AL_IKE_NONCE_PAYLOAD_LENGTH].Setup = DetectIkeNoncePayloadLengthSetup;
  62     sigmatch_table[DETECT_AL_IKE_NONCE_PAYLOAD_LENGTH].Free = DetectIkeNoncePayloadLengthFree;
  63
  64     DetectAppLayerInspectEngineRegister2("ike.nonce_payload_length", ALPROTO_IKE, SIG_FLAG_TOSERVER,
  65             1, DetectEngineInspectIkeNoncePayloadLengthGeneric, NULL);
  66
  67     DetectAppLayerInspectEngineRegister2("ike.nonce_payload_length", ALPROTO_IKE, SIG_FLAG_TOCLIENT,
  68             1, DetectEngineInspectIkeNoncePayloadLengthGeneric, NULL);
  69
  70     g_ike_nonce_payload_length_buffer_id = DetectBufferTypeGetByName("ike.nonce_payload_length");
  71
  72     DetectUintRegister();
  73 }
  74
  75 static int DetectEngineInspectIkeNoncePayloadLengthGeneric(DetectEngineCtx *de_ctx,
  76         DetectEngineThreadCtx *det_ctx, const struct DetectEngineAppInspectionEngine_ *engine,
  77         const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
  78 {
  79     return DetectEngineInspectGenericList(
  80             de_ctx, det_ctx, s, engine->smd, f, flags, alstate, txv, tx_id);
  81 }
  82
  83 /**
  84  * \internal
  85  * \brief Function to match nonce length of a IKE state
  86  *
  87  * \param det_ctx Pointer to the pattern matcher thread.
  88  * \param f       Pointer to the current flow.
  89  * \param flags   Flags.
  90  * \param state   App layer state.
  91  * \param txv     Pointer to the Ike Transaction.
  92  * \param s       Pointer to the Signature.
  93  * \param ctx     Pointer to the sigmatch that we will cast into DetectU32Data.
  94  *
  95  * \retval 0 no match.
  96  * \retval 1 match.
  97  */
  98 static int DetectIkeNoncePayloadLengthMatch(DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags,
  99         void *state, void *txv, const Signature *s, const SigMatchCtx *ctx)
 100 {
 101     SCEnter();
 102
 103     uint32_t length;
 104     if (!rs_ike_state_get_nonce_payload_length(txv, &length))
 105         SCReturnInt(0);
 106     const DetectU32Data *du32 = (const DetectU32Data *)ctx;
 107     return DetectU32Match(length, du32);
 108 }
 109
 110 /**
 111  * \brief Function to add the parsed IKE nonce length field into the current signature.
 112  *
 113  * \param de_ctx Pointer to the Detection Engine Context.
 114  * \param s      Pointer to the Current Signature.
 115  * \param rawstr Pointer to the user provided flags options.
 116  *
 117  * \retval 0 on Success.
 118  * \retval -1 on Failure.
 119  */
 120 static int DetectIkeNoncePayloadLengthSetup(
 121         DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
 122 {
 123     if (DetectSignatureSetAppProto(s, ALPROTO_IKE) != 0)
 124         return -1;
 125
 126     DetectU32Data *nonce_payload_length = DetectU32Parse(rawstr);
 127     if (nonce_payload_length == NULL)
 128         return -1;
 129
 130     /* okay so far so good, lets get this into a SigMatch
 131      * and put it in the Signature. */
 132     SigMatch *sm = SigMatchAlloc();
 133     if (sm == NULL)
 134         goto error;
 135
 136     sm->type = DETECT_AL_IKE_NONCE_PAYLOAD_LENGTH;
 137     sm->ctx = (SigMatchCtx *)nonce_payload_length;
 138
 139     SigMatchAppendSMToList(s, sm, g_ike_nonce_payload_length_buffer_id);
 140     return 0;
 141
 142 error:
 143     DetectIkeNoncePayloadLengthFree(de_ctx, nonce_payload_length);
 144     return -1;
 145 }
 146
 147 /**
 148  * \internal
 149  * \brief Function to free memory associated with DetectU32Data.
 150  *
 151  * \param de_ptr Pointer to DetectU32Data.
 152  */
 153 static void DetectIkeNoncePayloadLengthFree(DetectEngineCtx *de_ctx, void *ptr)
 154 {
 155     SCFree(ptr);
 156 }