1 files changed, 116 insertions, 0 deletions
diff --git a/src/detect-snmp-community.c b/src/detect-snmp-community.c
new file mode 100644
index 0000000..93e7d21
--- /dev/null
+++ b/src/detect-snmp-community.c
@@ -0,0 +1,116 @@
+/* Copyright (C) 2015-2019 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 Pierre Chifflier <chifflier@wzdftpd.net>
+ *
+ * Set up of the "snmp.community" keyword to allow content
+ * inspections on the decoded snmp community.
+ */
+
+#include "suricata-common.h"
+#include "conf.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-snmp-community.h"
+#include "app-layer-parser.h"
+#include "rust.h"
+
+static int DetectSNMPCommunitySetup(DetectEngineCtx *, Signature *,
+    const char *);
+static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
+       const DetectEngineTransforms *transforms,
+       Flow *f, const uint8_t flow_flags,
+       void *txv, const int list_id);
+#ifdef UNITTESTS
+static void DetectSNMPCommunityRegisterTests(void);
+#endif
+static int g_snmp_rust_id = 0;
+
+void DetectSNMPCommunityRegister(void)
+{
+    sigmatch_table[DETECT_AL_SNMP_COMMUNITY].name = "snmp.community";
+    sigmatch_table[DETECT_AL_SNMP_COMMUNITY].desc =
+        "SNMP content modifier to match on the SNMP community";
+    sigmatch_table[DETECT_AL_SNMP_COMMUNITY].Setup =
+        DetectSNMPCommunitySetup;
+#ifdef UNITTESTS
+    sigmatch_table[DETECT_AL_SNMP_COMMUNITY].RegisterTests = DetectSNMPCommunityRegisterTests;
+#endif
+    sigmatch_table[DETECT_AL_SNMP_COMMUNITY].url = "/rules/snmp-keywords.html#snmp-community";
+
+    sigmatch_table[DETECT_AL_SNMP_COMMUNITY].flags |= SIGMATCH_NOOPT|SIGMATCH_INFO_STICKY_BUFFER;
+
+    /* register inspect engines */
+    DetectAppLayerInspectEngineRegister2("snmp.community",
+            ALPROTO_SNMP, SIG_FLAG_TOSERVER, 0,
+            DetectEngineInspectBufferGeneric, GetData);
+    DetectAppLayerMpmRegister2("snmp.community", SIG_FLAG_TOSERVER, 2,
+            PrefilterGenericMpmRegister, GetData, ALPROTO_SNMP, 0);
+    DetectAppLayerInspectEngineRegister2("snmp.community",
+            ALPROTO_SNMP, SIG_FLAG_TOCLIENT, 0,
+            DetectEngineInspectBufferGeneric, GetData);
+    DetectAppLayerMpmRegister2("snmp.community", SIG_FLAG_TOCLIENT, 2,
+            PrefilterGenericMpmRegister, GetData, ALPROTO_SNMP, 0);
+
+    DetectBufferTypeSetDescriptionByName("snmp.community", "SNMP Community identifier");
+
+    g_snmp_rust_id = DetectBufferTypeGetByName("snmp.community");
+}
+
+static int DetectSNMPCommunitySetup(DetectEngineCtx *de_ctx, Signature *s,
+    const char *str)
+{
+    if (DetectBufferSetActiveList(de_ctx, s, g_snmp_rust_id) < 0)
+        return -1;
+
+    if (DetectSignatureSetAppProto(s, ALPROTO_SNMP) != 0)
+        return -1;
+
+    return 0;
+}
+
+static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
+        const DetectEngineTransforms *transforms, Flow *f,
+        const uint8_t flow_flags, void *txv, const int list_id)
+{
+    InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
+    if (buffer->inspect == NULL) {
+        uint32_t data_len = 0;
+        const uint8_t *data = NULL;
+
+        rs_snmp_tx_get_community(txv, &data, &data_len);
+        if (data == NULL || data_len == 0) {
+            return NULL;
+        }
+
+        InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
+        InspectionBufferApplyTransforms(buffer, transforms);
+    }
+
+    return buffer;
+}
+
+#ifdef UNITTESTS
+#include "tests/detect-snmp-community.c"
+#endif /* UNITTESTS */