Adding upstream version 1:7.0.3.upstream/1%7.0.3

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 191 insertions, 0 deletions

diff --git a/src/detect-depth.c b/src/detect-depth.c
new file mode 100644
index 0000000..1c4f94a
--- /dev/null
+++ b/src/detect-depth.c
@@ -0,0 +1,191 @@
+/* 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>
+ * \author Anoop Saldanha <anoopsaldanha@gmail.com>
+ *
+ * Implements the depth keyword.
+ */
+
+#include "suricata-common.h"
+
+#include "decode.h"
+
+#include "detect.h"
+#include "detect-parse.h"
+#include "detect-content.h"
+#include "detect-uricontent.h"
+#include "detect-byte.h"
+#include "detect-byte-extract.h"
+#include "detect-depth.h"
+
+#include "flow-var.h"
+#include "app-layer.h"
+
+#include "util-byte.h"
+#include "util-debug.h"
+
+static int DetectDepthSetup (DetectEngineCtx *, Signature *, const char *);
+static int DetectStartsWithSetup (DetectEngineCtx *, Signature *, const char *);
+
+void DetectDepthRegister (void)
+{
+    sigmatch_table[DETECT_DEPTH].name = "depth";
+    sigmatch_table[DETECT_DEPTH].desc = "designate how many bytes from the beginning of the payload will be checked";
+    sigmatch_table[DETECT_DEPTH].url = "/rules/payload-keywords.html#depth";
+    sigmatch_table[DETECT_DEPTH].Match = NULL;
+    sigmatch_table[DETECT_DEPTH].Setup = DetectDepthSetup;
+    sigmatch_table[DETECT_DEPTH].Free  = NULL;
+
+    sigmatch_table[DETECT_STARTS_WITH].name = "startswith";
+    sigmatch_table[DETECT_STARTS_WITH].desc = "pattern must be at the start of a buffer (same as 'depth:<pattern len>')";
+    sigmatch_table[DETECT_STARTS_WITH].url = "/rules/payload-keywords.html#startswith";
+    sigmatch_table[DETECT_STARTS_WITH].Setup = DetectStartsWithSetup;
+    sigmatch_table[DETECT_STARTS_WITH].flags |= SIGMATCH_NOOPT;
+}
+
+static int DetectDepthSetup (DetectEngineCtx *de_ctx, Signature *s, const char *depthstr)
+{
+    const char *str = depthstr;
+    SigMatch *pm = NULL;
+    int ret = -1;
+
+    /* retrieve the sm to apply the depth against */
+    pm = DetectGetLastSMFromLists(s, DETECT_CONTENT, -1);
+    if (pm == NULL) {
+        SCLogError("depth needs "
+                   "preceding content, uricontent option, http_client_body, "
+                   "http_server_body, http_header option, http_raw_header option, "
+                   "http_method option, http_cookie, http_raw_uri, "
+                   "http_stat_msg, http_stat_code, http_user_agent, "
+                   "http_host, http_raw_host or "
+                   "file_data/dce_stub_data sticky buffer options.");
+        goto end;
+    }
+
+    /* verify other conditions. */
+    DetectContentData *cd = (DetectContentData *)pm->ctx;
+
+    if (cd->flags & DETECT_CONTENT_DEPTH) {
+        SCLogError("can't use multiple depths for the same content.");
+        goto end;
+    }
+    if ((cd->flags & DETECT_CONTENT_WITHIN) || (cd->flags & DETECT_CONTENT_DISTANCE)) {
+        SCLogError("can't use a relative "
+                   "keyword like within/distance with a absolute "
+                   "relative keyword like depth/offset for the same "
+                   "content.");
+        goto end;
+    }
+    if (cd->flags & DETECT_CONTENT_NEGATED && cd->flags & DETECT_CONTENT_FAST_PATTERN) {
+        SCLogError("can't have a relative "
+                   "negated keyword set along with 'fast_pattern'.");
+        goto end;
+    }
+    if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
+        SCLogError("can't have a relative "
+                   "keyword set along with 'fast_pattern:only;'.");
+        goto end;
+    }
+    if (str[0] != '-' && isalpha((unsigned char)str[0])) {
+        DetectByteIndexType index;
+        if (!DetectByteRetrieveSMVar(str, s, &index)) {
+            SCLogError("unknown byte_ keyword var "
+                       "seen in depth - %s.",
+                    str);
+            goto end;
+        }
+        cd->depth = index;
+        cd->flags |= DETECT_CONTENT_DEPTH_VAR;
+    } else {
+        if (StringParseUint16(&cd->depth, 0, 0, str) < 0)
+        {
+            SCLogError("invalid value for depth: %s.", str);
+            goto end;
+        }
+
+        if (cd->depth < cd->content_len) {
+            SCLogError("depth:%u smaller than "
+                       "content of len %u.",
+                    cd->depth, cd->content_len);
+            return -1;
+        }
+        /* Now update the real limit, as depth is relative to the offset */
+        cd->depth += cd->offset;
+    }
+    cd->flags |= DETECT_CONTENT_DEPTH;
+
+    ret = 0;
+ end:
+    return ret;
+}
+
+static int DetectStartsWithSetup (DetectEngineCtx *de_ctx, Signature *s, const char *unused)
+{
+    SigMatch *pm = NULL;
+    int ret = -1;
+
+    /* retrieve the sm to apply the depth against */
+    pm = DetectGetLastSMFromLists(s, DETECT_CONTENT, -1);
+    if (pm == NULL) {
+        SCLogError("startswith needs a "
+                   "preceding content option.");
+        goto end;
+    }
+
+    /* verify other conditions. */
+    DetectContentData *cd = (DetectContentData *)pm->ctx;
+
+    if (cd->flags & DETECT_CONTENT_DEPTH) {
+        SCLogError("can't use multiple "
+                   "depth/startswith settings for the same content.");
+        goto end;
+    }
+    if ((cd->flags & DETECT_CONTENT_WITHIN) || (cd->flags & DETECT_CONTENT_DISTANCE)) {
+        SCLogError("can't use a relative "
+                   "keyword like within/distance with a absolute "
+                   "relative keyword like depth/offset for the same "
+                   "content.");
+        goto end;
+    }
+    if (cd->flags & DETECT_CONTENT_NEGATED && cd->flags & DETECT_CONTENT_FAST_PATTERN) {
+        SCLogError("can't have a relative "
+                   "negated keyword set along with a 'fast_pattern'.");
+        goto end;
+    }
+    if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) {
+        SCLogError("can't have a relative "
+                   "keyword set along with 'fast_pattern:only;'.");
+        goto end;
+    }
+    if (cd->flags & DETECT_CONTENT_OFFSET) {
+        SCLogError("can't mix offset "
+                   "with startswith.");
+        goto end;
+    }
+
+    cd->depth = cd->content_len;
+    cd->flags |= DETECT_CONTENT_DEPTH;
+    cd->flags |= DETECT_CONTENT_STARTS_WITH;
+
+    ret = 0;
+ end:
+    return ret;
+}