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-rw-r--r--src/detect-asn1.c459
1 files changed, 459 insertions, 0 deletions
diff --git a/src/detect-asn1.c b/src/detect-asn1.c
new file mode 100644
index 0000000..e255e05
--- /dev/null
+++ b/src/detect-asn1.c
@@ -0,0 +1,459 @@
+/* Copyright (C) 2020-2022 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-asn1.c
+ *
+ * Implements "asn1" keyword
+ */
+
+#include "suricata-common.h"
+#include "decode.h"
+#include "rust.h"
+
+#include "detect.h"
+#include "detect-parse.h"
+
+#include "flow.h"
+#include "detect-asn1.h"
+
+#include "util-unittest.h"
+#include "util-unittest-helper.h"
+#include "util-byte.h"
+#include "util-debug.h"
+
+static int DetectAsn1Match(DetectEngineThreadCtx *, Packet *,
+ const Signature *, const SigMatchCtx *);
+static int DetectAsn1Setup (DetectEngineCtx *, Signature *, const char *);
+#ifdef UNITTESTS
+static void DetectAsn1RegisterTests(void);
+#endif
+static void DetectAsn1Free(DetectEngineCtx *, void *);
+
+/**
+ * \brief Registration function for asn1
+ */
+void DetectAsn1Register(void)
+{
+ sigmatch_table[DETECT_ASN1].name = "asn1";
+ sigmatch_table[DETECT_ASN1].Match = DetectAsn1Match;
+ sigmatch_table[DETECT_ASN1].Setup = DetectAsn1Setup;
+ sigmatch_table[DETECT_ASN1].Free = DetectAsn1Free;
+#ifdef UNITTESTS
+ sigmatch_table[DETECT_ASN1].RegisterTests = DetectAsn1RegisterTests;
+#endif
+}
+
+/**
+ * \brief This function will decode the asn1 data and inspect the resulting
+ * nodes to detect if any of the specified checks match this data
+ *
+ * \param det_ctx pointer to the detect engine thread context
+ * \param p pointer to the current packet
+ * \param s pointer to the signature
+ * \param ctx pointer to the sigmatch that we will cast into `DetectAsn1Data`
+ *
+ * \retval 1 match
+ * \retval 0 no match
+ */
+static int DetectAsn1Match(DetectEngineThreadCtx *det_ctx, Packet *p,
+ const Signature *s, const SigMatchCtx *ctx)
+{
+ uint8_t ret = 0;
+
+ if (p->payload_len == 0) {
+ /* No error, parser done, no data in bounds to decode */
+ return 0;
+ }
+
+ const DetectAsn1Data *ad = (const DetectAsn1Data *)ctx;
+
+ Asn1 *asn1 = rs_asn1_decode(p->payload, p->payload_len, det_ctx->buffer_offset, ad);
+
+ ret = rs_asn1_checks(asn1, ad);
+
+ rs_asn1_free(asn1);
+
+ return ret;
+}
+
+/**
+ * \brief This function is used to parse asn1 options passed via asn1: keyword
+ *
+ * \param asn1str pointer to the user provided asn1 options
+ *
+ * \retval pointer to `DetectAsn1Data` on success
+ * \retval NULL on failure
+ */
+static DetectAsn1Data *DetectAsn1Parse(const char *asn1str)
+{
+ DetectAsn1Data *ad = rs_detect_asn1_parse(asn1str);
+
+ if (ad == NULL) {
+ SCLogError("Malformed asn1 argument: %s", asn1str);
+ }
+
+ return ad;
+}
+
+/**
+ * \brief this function is used to add the parsed asn1 data into
+ * the current signature
+ *
+ * \param de_ctx pointer to the detection engine context
+ * \param s pointer to the current signature
+ * \param asn1str pointer to the user provided asn1 options
+ *
+ * \retval 0 on success
+ * \retval -1 on failure
+ */
+static int DetectAsn1Setup(DetectEngineCtx *de_ctx, Signature *s, const char *asn1str)
+{
+ DetectAsn1Data *ad = DetectAsn1Parse(asn1str);
+ if (ad == NULL)
+ return -1;
+
+ /* Okay so far so good, lets get this into a SigMatch
+ * and put it in the Signature. */
+ SigMatch *sm = SigMatchAlloc();
+ if (sm == NULL) {
+ DetectAsn1Free(de_ctx, ad);
+ return -1;
+ }
+
+ sm->type = DETECT_ASN1;
+ sm->ctx = (SigMatchCtx *)ad;
+
+ SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_MATCH);
+
+ return 0;
+}
+
+/**
+ * \brief this function will free memory associated with `DetectAsn1Data`
+ *
+ * \param de_ctx pointer to the detection engine context
+ * \param ptr point to `DetectAsn1Data`
+ */
+static void DetectAsn1Free(DetectEngineCtx *de_ctx, void *ptr)
+{
+ DetectAsn1Data *ad = (DetectAsn1Data *)ptr;
+ rs_detect_asn1_free(ad);
+}
+
+#ifdef UNITTESTS
+
+/**
+ * \test DetectAsn1TestReal01 Ensure that all works together
+ */
+static int DetectAsn1TestReal01(void)
+{
+ uint8_t *buf = (uint8_t *) "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01"
+ "P""\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111"
+ "\x31\x1F\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05"
+ "Jones""\xA0\x0A\x43\x08""19590717"
+ "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01""P"
+ "\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111""\x31\x1F"
+ "\x61\x11\x1A\x05""Pablo""\x1A\x01""B""\x1A\x05""Jones"
+ "\xA0\x0A\x43\x08""19590717";
+
+ uint16_t buflen = strlen((char *)buf) - 1;
+
+ /* Check the start with AA (this is to test the relative_offset keyword) */
+ uint8_t *buf2 = (uint8_t *) "AA\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01"
+ "P""\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111"
+ "\x31\x1F\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05"
+ "Jones""\xA0\x0A\x43\x08""19590717"
+ "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01""P"
+ "\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111""\x31\x1F"
+ "\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05""Jones"
+ "\xA0\x0A\x43\x08""19590717";
+
+ uint16_t buflen2 = strlen((char *)buf2) - 1;
+
+ Packet *p[2];
+
+ p[0] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
+ FAIL_IF_NULL(p[0]);
+ p[1] = UTHBuildPacket((uint8_t *)buf2, buflen2, IPPROTO_TCP);
+ FAIL_IF_NULL(p[1]);
+
+ const char *sigs[3];
+ sigs[0]= "alert ip any any -> any any (msg:\"Testing id 1\"; "
+ "content:\"Pablo\"; asn1:absolute_offset 0, "
+ "oversize_length 130; sid:1;)";
+ sigs[1]= "alert ip any any -> any any (msg:\"Testing id 2\"; "
+ "content:\"AA\"; asn1:relative_offset 0, "
+ "oversize_length 130; sid:2;)";
+ sigs[2]= "alert ip any any -> any any (msg:\"Testing id 3\"; "
+ "content:\"lalala\"; asn1: oversize_length 2000; sid:3;)";
+
+ uint32_t sid[3] = {1, 2, 3};
+ uint32_t results[2][3] = {
+ /* packet 0 match sid 1 */
+ {1, 0, 0},
+ /* packet 1 match sid 2 */
+ {0, 1, 0}};
+ /* None of the packets should match sid 3 */
+ FAIL_IF_NOT(UTHGenericTest(p, 2, sigs, sid, (uint32_t *)results, 3) == 1);
+
+ UTHFreePackets(p, 2);
+ PASS;
+}
+
+/**
+ * \test DetectAsn1TestReal02 Ensure that all works together
+ */
+static int DetectAsn1TestReal02(void)
+{
+ int result = 0;
+ uint8_t *buf = (uint8_t *) "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01"
+ "P""\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111"
+ "\x31\x1F\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05"
+ "Jones""\xA0\x0A\x43\x08""19590717"
+ "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01""P"
+ "\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111""\x31\x1F"
+ "\x61\x11\x1A\x05""Pablo""\x1A\x01""B""\x1A\x05""Jones"
+ "\xA0\x0A\x43\x08""19590717";
+
+ uint16_t buflen = strlen((char *)buf) - 1;
+
+ /* Check the start with AA (this is to test the relative_offset keyword) */
+ uint8_t *buf2 = (uint8_t *) "AA\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01"
+ "P""\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111"
+ "\x31\x1F\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05"
+ "Jones""\xA0\x0A\x43\x08""19590717"
+ "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01""P"
+ "\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111""\x31\x1F"
+ "\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05""Jones"
+ "\xA0\x0A\x43\x08""19590717";
+
+ uint16_t buflen2 = strlen((char *)buf2) - 1;
+
+ Packet *p[2];
+
+ p[0] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
+ p[1] = UTHBuildPacket((uint8_t *)buf2, buflen2, IPPROTO_TCP);
+
+ if (p[0] == NULL || p[1] == NULL)
+ goto end;
+
+ const char *sigs[3];
+ sigs[0]= "alert ip any any -> any any (msg:\"Testing id 1\"; "
+ "content:\"Pablo\"; asn1:absolute_offset 0, "
+ "oversize_length 140; sid:1;)";
+ sigs[1]= "alert ip any any -> any any (msg:\"Testing id 2\"; "
+ "content:\"AA\"; asn1:relative_offset 0, "
+ "oversize_length 140; sid:2;)";
+ sigs[2]= "alert ip any any -> any any (msg:\"Testing id 3\"; "
+ "content:\"lalala\"; asn1: oversize_length 2000; sid:3;)";
+
+ uint32_t sid[3] = {1, 2, 3};
+
+ uint32_t results[2][3] = {
+ {0, 0, 0},
+ {0, 0, 0}};
+ /* None of the packets should match */
+
+ result = UTHGenericTest(p, 2, sigs, sid, (uint32_t *) results, 3);
+
+ UTHFreePackets(p, 2);
+end:
+ return result;
+}
+
+/**
+ * \test DetectAsn1TestReal03 Ensure that all works together
+ */
+static int DetectAsn1TestReal03(void)
+{
+ int result = 0;
+ uint8_t buf[261] = "";
+ /* universal class, primitive type, tag_num = 9 (Data type Real) */
+ buf[0] = '\x09';
+ /* length, definite form, 2 octets */
+ buf[1] = '\x82';
+ /* length is the sum of the following octets (257): */
+ buf[2] = '\x01';
+ buf[3] = '\x01';
+
+ /* Fill the content of the number */
+ uint16_t i = 4;
+ for (; i < 257;i++)
+ buf[i] = '\x05';
+
+ uint16_t buflen = 261;
+
+ /* Check the start with AA (this is to test the relative_offset keyword) */
+ uint8_t *buf2 = (uint8_t *) "AA\x03\x01\xFF";
+
+ uint16_t buflen2 = 5;
+
+ Packet *p[2] = { NULL, NULL };
+
+ p[0] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
+ p[1] = UTHBuildPacket((uint8_t *)buf2, buflen2, IPPROTO_TCP);
+
+ if (p[0] == NULL || p[1] == NULL)
+ goto end;
+
+ const char *sigs[3];
+ /* This should match the first packet */
+ sigs[0]= "alert ip any any -> any any (msg:\"Testing id 1\"; "
+ "asn1:absolute_offset 0, double_overflow; sid:1;)";
+ /* This should match the second packet */
+ sigs[1]= "alert ip any any -> any any (msg:\"Testing id 2\"; "
+ "asn1:relative_offset 2, bitstring_overflow,"
+ "oversize_length 140; sid:2;)";
+ /* This should match no packet */
+ sigs[2]= "alert ip any any -> any any (msg:\"Testing id 3\"; "
+ "asn1: oversize_length 2000; sid:3;)";
+
+ uint32_t sid[3] = {1, 2, 3};
+
+ uint32_t results[2][3] = {{1, 0, 0},
+ {0, 1, 0}};
+
+ result = UTHGenericTest(p, 2, sigs, sid, (uint32_t *) results, 3);
+
+ UTHFreePackets(p, 2);
+end:
+ return result;
+}
+
+/**
+ * \test DetectAsn1TestReal04 like the real test 02, but modified the
+ * relative offset to check negative offset values, in this case
+ * start decoding from -7 bytes respect the content match "John"
+ */
+static int DetectAsn1TestReal04(void)
+{
+ int result = 0;
+ uint8_t *buf = (uint8_t *) "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01"
+ "P""\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111"
+ "\x31\x1F\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05"
+ "Jones""\xA0\x0A\x43\x08""19590717"
+ "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01""P"
+ "\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111""\x31\x1F"
+ "\x61\x11\x1A\x05""Pablo""\x1A\x01""B""\x1A\x05""Jones"
+ "\xA0\x0A\x43\x08""19590717";
+
+ uint16_t buflen = strlen((char *)buf) - 1;
+
+ /* Check the start with AA (this is to test the relative_offset keyword) */
+ uint8_t *buf2 = (uint8_t *) "AA\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01"
+ "P""\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111"
+ "\x31\x1F\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05"
+ "Jones""\xA0\x0A\x43\x08""19590717"
+ "\x60\x81\x85\x61\x10\x1A\x04""John""\x1A\x01""P"
+ "\x1A\x05""Smith""\xA0\x0A\x1A\x08""Director"
+ "\x42\x01\x33\xA1\x0A\x43\x08""19710917"
+ "\xA2\x12\x61\x10\x1A\x04""Mary""\x1A\x01""T""\x1A\x05"
+ "Smith""\xA3\x42\x31\x1F\x61\x11\x1A\x05""Ralph""\x1A\x01"
+ "T""\x1A\x05""Smith""\xA0\x0A\x43\x08""19571111""\x31\x1F"
+ "\x61\x11\x1A\x05""Susan""\x1A\x01""B""\x1A\x05""Jones"
+ "\xA0\x0A\x43\x08""19590717";
+
+ uint16_t buflen2 = strlen((char *)buf2) - 1;
+
+ Packet *p[2];
+
+ p[0] = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP);
+ p[1] = UTHBuildPacket((uint8_t *)buf2, buflen2, IPPROTO_TCP);
+
+ if (p[0] == NULL || p[1] == NULL)
+ goto end;
+
+ const char *sigs[3];
+ sigs[0]= "alert ip any any -> any any (msg:\"Testing id 1\"; "
+ "content:\"Pablo\"; asn1:absolute_offset 0, "
+ "oversize_length 140; sid:1;)";
+ sigs[1]= "alert ip any any -> any any (msg:\"Testing id 2\"; "
+ "content:\"John\"; asn1:relative_offset -11, "
+ "oversize_length 140; sid:2;)";
+ sigs[2]= "alert ip any any -> any any (msg:\"Testing id 3\"; "
+ "content:\"lalala\"; asn1: oversize_length 2000; sid:3;)";
+
+ uint32_t sid[3] = {1, 2, 3};
+
+ uint32_t results[2][3] = {
+ {0, 0, 0},
+ {0, 0, 0}};
+ /* None of the packets should match */
+
+ result = UTHGenericTest(p, 2, sigs, sid, (uint32_t *) results, 3);
+
+ UTHFreePackets(p, 2);
+end:
+ return result;
+}
+
+/**
+ * \brief this function registers unit tests for DetectAsn1
+ */
+static void DetectAsn1RegisterTests(void)
+{
+ UtRegisterTest("DetectAsn1TestReal01", DetectAsn1TestReal01);
+ UtRegisterTest("DetectAsn1TestReal02", DetectAsn1TestReal02);
+ UtRegisterTest("DetectAsn1TestReal03", DetectAsn1TestReal03);
+ UtRegisterTest("DetectAsn1TestReal04", DetectAsn1TestReal04);
+}
+#endif /* UNITTESTS */
generated by cgit v1.2.3 (git 2.39.1) at 2025-02-24 00:06:19 +0000