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, 159 insertions, 0 deletions

diff --git a/src/detect-transform-pcrexform.c b/src/detect-transform-pcrexform.c
new file mode 100644
index 0000000..c517175
--- /dev/null
+++ b/src/detect-transform-pcrexform.c
@@ -0,0 +1,159 @@
+/* Copyright (C) 2020 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 Jeff Lucovsky <jeff@lucovsky.org>
+ *
+ * Implements the pcrexform transform keyword with option support
+ */
+
+#include "suricata-common.h"
+
+#include "detect.h"
+#include "detect-engine.h"
+#include "detect-parse.h"
+#include "detect-transform-pcrexform.h"
+#include "detect-pcre.h"
+
+typedef struct DetectTransformPcrexformData {
+    pcre2_code *regex;
+    pcre2_match_context *context;
+} DetectTransformPcrexformData;
+
+static int DetectTransformPcrexformSetup (DetectEngineCtx *, Signature *, const char *);
+static void DetectTransformPcrexformFree(DetectEngineCtx *, void *);
+static void DetectTransformPcrexform(InspectionBuffer *buffer, void *options);
+#ifdef UNITTESTS
+void DetectTransformPcrexformRegisterTests (void);
+#endif
+
+void DetectTransformPcrexformRegister(void)
+{
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].name = "pcrexform";
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].desc =
+        "modify buffer via PCRE before inspection";
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].url = "/rules/transforms.html#pcre-xform";
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].Transform =
+        DetectTransformPcrexform;
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].Free =
+        DetectTransformPcrexformFree;
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].Setup =
+        DetectTransformPcrexformSetup;
+#ifdef UNITTESTS
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].RegisterTests = DetectTransformPcrexformRegisterTests;
+#endif
+    sigmatch_table[DETECT_TRANSFORM_PCREXFORM].flags |= SIGMATCH_QUOTES_MANDATORY;
+}
+
+static void DetectTransformPcrexformFree(DetectEngineCtx *de_ctx, void *ptr)
+{
+    if (ptr != NULL) {
+        DetectTransformPcrexformData *pxd = (DetectTransformPcrexformData *) ptr;
+        pcre2_match_context_free(pxd->context);
+        pcre2_code_free(pxd->regex);
+        SCFree(pxd);
+    }
+}
+
+/**
+ *  \internal
+ *  \brief Apply the pcrexform keyword to the last pattern match
+ *  \param det_ctx detection engine ctx
+ *  \param s signature
+ *  \param regexstr options string
+ *  \retval 0 ok
+ *  \retval -1 failure
+ */
+static int DetectTransformPcrexformSetup (DetectEngineCtx *de_ctx, Signature *s, const char *regexstr)
+{
+    SCEnter();
+
+    // Create pxd from regexstr
+    DetectTransformPcrexformData *pxd = SCCalloc(1, sizeof(*pxd));
+    if (pxd == NULL) {
+        SCLogDebug("pxd allocation failed");
+        SCReturnInt(-1);
+    }
+
+    pxd->context = pcre2_match_context_create(NULL);
+    if (pxd->context == NULL) {
+        SCFree(pxd);
+        SCReturnInt(-1);
+    }
+    pcre2_set_match_limit(pxd->context, SC_MATCH_LIMIT_DEFAULT);
+    pcre2_set_recursion_limit(pxd->context, SC_MATCH_LIMIT_RECURSION_DEFAULT);
+    int en;
+    PCRE2_SIZE eo;
+    pxd->regex = pcre2_compile((PCRE2_SPTR8)regexstr, PCRE2_ZERO_TERMINATED, 0, &en, &eo, NULL);
+    if (pxd->regex == NULL) {
+        PCRE2_UCHAR buffer[256];
+        pcre2_get_error_message(en, buffer, sizeof(buffer));
+        SCLogError("pcre2 compile of \"%s\" failed at "
+                   "offset %d: %s",
+                regexstr, (int)eo, buffer);
+        pcre2_match_context_free(pxd->context);
+        SCFree(pxd);
+        SCReturnInt(-1);
+    }
+    // check pcd->regex has exactly one capture expression
+    uint32_t nb;
+    if (pcre2_pattern_info(pxd->regex, PCRE2_INFO_CAPTURECOUNT, &nb) < 0) {
+        SCLogError("pcrexform failed getting info about capturecount");
+        DetectTransformPcrexformFree(de_ctx, pxd);
+        SCReturnInt(-1);
+    }
+    if (nb != 1) {
+        SCLogError("pcrexform needs exactly one substring capture, found %" PRIu32, nb);
+        DetectTransformPcrexformFree(de_ctx, pxd);
+        SCReturnInt(-1);
+    }
+
+    int r = DetectSignatureAddTransform(s, DETECT_TRANSFORM_PCREXFORM, pxd);
+    if (r != 0) {
+        DetectTransformPcrexformFree(de_ctx, pxd);
+    }
+
+    SCReturnInt(r);
+}
+
+static void DetectTransformPcrexform(InspectionBuffer *buffer, void *options)
+{
+    const char *input = (const char *)buffer->inspect;
+    const uint32_t input_len = buffer->inspect_len;
+    DetectTransformPcrexformData *pxd = options;
+
+    pcre2_match_data *match = pcre2_match_data_create_from_pattern(pxd->regex, NULL);
+    int ret = pcre2_match(pxd->regex, (PCRE2_SPTR8)input, input_len, 0, 0, match, pxd->context);
+
+    if (ret > 0) {
+        const char *str;
+        PCRE2_SIZE caplen;
+        ret = pcre2_substring_get_bynumber(match, 1, (PCRE2_UCHAR8 **)&str, &caplen);
+
+        if (ret >= 0) {
+            InspectionBufferCopy(buffer, (uint8_t *)str, (uint32_t)caplen);
+            pcre2_substring_free((PCRE2_UCHAR8 *)str);
+        }
+    }
+    pcre2_match_data_free(match);
+}
+
+#ifdef UNITTESTS
+#include "tests/detect-transform-pcrexform.c"
+#endif