1 files changed, 131 insertions, 0 deletions
diff --git a/src/detect-tcphdr.c b/src/detect-tcphdr.c
new file mode 100644
index 0000000..f054e35
--- /dev/null
+++ b/src/detect-tcphdr.c
@@ -0,0 +1,131 @@
+/* Copyright (C) 2007-2019 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 Victor Julien <victor@inliniac.net>
+ *
+ */
+
+#include "suricata-common.h"
+
+#include "detect.h"
+#include "detect-parse.h"
+#include "detect-engine.h"
+#include "detect-engine-mpm.h"
+#include "detect-engine-prefilter.h"
+#include "detect-engine-content-inspection.h"
+#include "detect-fast-pattern.h"
+#include "detect-tcphdr.h"
+
+/* prototypes */
+static int DetectTcphdrSetup (DetectEngineCtx *, Signature *, const char *);
+#ifdef UNITTESTS
+void DetectTcphdrRegisterTests (void);
+#endif
+
+static int g_tcphdr_buffer_id = 0;
+
+static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
+        const DetectEngineTransforms *transforms, Packet *p, const int list_id);
+
+/**
+ * \brief Registration function for tcp.hdr: keyword
+ */
+void DetectTcphdrRegister(void)
+{
+    sigmatch_table[DETECT_TCPHDR].name = "tcp.hdr";
+    sigmatch_table[DETECT_TCPHDR].desc = "sticky buffer to match on the TCP header";
+    sigmatch_table[DETECT_TCPHDR].url = "/rules/header-keywords.html#tcphdr";
+    sigmatch_table[DETECT_TCPHDR].Setup = DetectTcphdrSetup;
+    sigmatch_table[DETECT_TCPHDR].flags |= SIGMATCH_NOOPT | SIGMATCH_INFO_STICKY_BUFFER;
+#ifdef UNITTESTS
+    sigmatch_table[DETECT_TCPHDR].RegisterTests = DetectTcphdrRegisterTests;
+#endif
+
+    g_tcphdr_buffer_id = DetectBufferTypeRegister("tcp.hdr");
+    BUG_ON(g_tcphdr_buffer_id < 0);
+
+    DetectBufferTypeSupportsPacket("tcp.hdr");
+
+    DetectPktMpmRegister("tcp.hdr", 2, PrefilterGenericMpmPktRegister, GetData);
+
+    DetectPktInspectEngineRegister("tcp.hdr", GetData,
+            DetectEngineInspectPktBufferGeneric);
+
+    return;
+}
+
+/**
+ * \brief setup tcp.hdr sticky buffer
+ *
+ * \param de_ctx pointer to the Detection Engine Context
+ * \param s pointer to the Current Signature
+ * \param _unused unused
+ *
+ * \retval 0 on Success
+ * \retval -1 on Failure
+ */
+static int DetectTcphdrSetup (DetectEngineCtx *de_ctx, Signature *s, const char *_unused)
+{
+    if (!(DetectProtoContainsProto(&s->proto, IPPROTO_TCP)))
+        return -1;
+
+    s->flags |= SIG_FLAG_REQUIRE_PACKET;
+
+    if (DetectBufferSetActiveList(de_ctx, s, g_tcphdr_buffer_id) < 0)
+        return -1;
+
+    return 0;
+}
+
+static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
+        const DetectEngineTransforms *transforms, Packet *p, const int list_id)
+{
+    SCEnter();
+
+    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
+    if (buffer->inspect == NULL) {
+        if (p->tcph == NULL) {
+            // may happen when DecodeTCPPacket fails
+            // for instance with invalid header length
+            return NULL;
+        }
+        uint32_t hlen = TCP_GET_HLEN(p);
+        if (((uint8_t *)p->tcph + (ptrdiff_t)hlen) >
+                ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)))
+        {
+            SCLogDebug("data out of range: %p > %p",
+                    ((uint8_t *)p->tcph + (ptrdiff_t)hlen),
+                    ((uint8_t *)GET_PKT_DATA(p) + (ptrdiff_t)GET_PKT_LEN(p)));
+            return NULL;
+        }
+
+        const uint32_t data_len = hlen;
+        const uint8_t *data = (const uint8_t *)p->tcph;
+
+        InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
+        InspectionBufferApplyTransforms(buffer, transforms);
+    }
+
+    return buffer;
+}
+
+#ifdef UNITTESTS
+#include "tests/detect-tcphdr.c"
+#endif