plugins/semgrep: add csmock semgrep plugin

Resolves: https://issues.redhat.com/browse/OSH-57
Closes: #149

py/plugins/semgrep.py

@@ -0,0 +1,166 @@
+# Copyright (C) 2014 Red Hat, Inc.
+#
+# This file is part of csmock.
+#
+# csmock is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# any later version.
+#
+# csmock 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
+# along with csmock.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+
+# disable metrics to be sent to semgrep cloud
+SEMGREP_SEND_METRICS = "off"
+
+# FIXME: should we use a dedicated repo to maintain semgrep rules?
+SEMGREP_RULES_REPO = "https://git.prodsec.redhat.com/prodsec-services/masssast"
+
+SEMGREP_SCAN_DIR = "/builddir/build/BUILD"
+
+SEMGREP_SCAN_OUTPUT = "/builddir/semgrep-scan-results.sarif"
+
+SEMGREP_RULES_CACHE_DIR = "/var/tmp/csmock/semgrep"
+
+SEMGREP_SCAN_LOG = "/builddir/semgrep-scan.log"
+
+FILTER_CMD = f"csgrep '%s' --mode=json --prepend-path-prefix={SEMGREP_SCAN_DIR}/ > '%s'"
+
+
+class PluginProps:
+    def __init__(self):
+        self.description = (
+            "A fast, open-source, static analysis engine for finding bugs, "
+            "detecting dependency vulnerabilities, and enforcing code standards."
+        )
+
+        # include this plug-in in `csmock --all-tools`
+        self.stable = True
+
+
+class Plugin:
+    def __init__(self):
+        self.enabled = False
+        self.semgrep_bin = None
+
+    def get_props(self):
+        return PluginProps()
+
+    def enable(self):
+        self.enabled = True
+
+    def init_parser(self, parser):
+        parser.add_argument(
+            "--semgrep-metrics", default=SEMGREP_SEND_METRICS,
+            help="configures how usage metrics are sent to the Semgrep server")
+
+        parser.add_argument(
+            "--semgrep-rules-repo", default=SEMGREP_RULES_REPO,
+            help="downstream semgrep rules repo")
+
+        parser.add_argument(
+            "--semgrep-rules-refresh", action="store_true",
+            help="force clone/refresh latest rules from downstream repo")
+
+        parser.add_argument(
+            "--semgrep-scan-opts",
+            help="space-separated list of additional options passed to the 'semgrep scan' command")
+
+    def handle_args(self, parser, args, props):
+        if not self.enabled:
+            return
+
+        # download semgrep rules from downstream repo
+        def fetch_semgrep_rules_hook(results, props):
+            # use results.exec_cmd to install semgrep cli using pip
+            cmd = "python3 -m pip install --user semgrep"
+            ec = results.exec_cmd(cmd, shell=True)
+            if 0 != ec:
+                results.error("failed to install semgrep cli using pip")
+
+            try:
+                # make sure the cache directory exists
+                os.makedirs(SEMGREP_RULES_CACHE_DIR, mode=0o755, exist_ok=True)
+            except OSError:
+                results.error(f"failed to create semgrep cache directory: {SEMGREP_RULES_CACHE_DIR}")
+                return 1
+            # command to fetch semgrep rules
+            repo_clone_cmd = f"git clone {args.semgrep_rules_repo} {SEMGREP_RULES_CACHE_DIR}"
+
+            # check whether we can reuse previously downloaded semgrep rules
+            if not args.semgrep_rules_refresh and os.listdir(SEMGREP_RULES_CACHE_DIR):
+                results.print_with_ts(f"reusing previously downloaded semgrep rules: {SEMGREP_RULES_CACHE_DIR}")
+            else:
+                # remove previously downloaded semgrep repo/rules
+                results.exec_cmd(["rm", "-rf", f"{SEMGREP_RULES_CACHE_DIR}/*"])
+
+                # fetch semgrep rules from downstream repo
+                ec = results.exec_cmd(repo_clone_cmd.split())
+                if 0 != ec:
+                    results.error("failed to fetch semgrep rules from downstream repo")
+                    return ec
+            # query version of semgrep
+            semgrep_bin_dir = os.path.abspath("./.local/bin")
+            semgrep_bin = f"{semgrep_bin_dir}/semgrep"
+            self.semgrep_bin = semgrep_bin
+            (ec, out) = results.get_cmd_output([f"{self.semgrep_bin}", "--version"], shell=False)
+            if 0 != ec:
+                results.error("failed to query semgrep cli version", ec=ec)
+                return ec
+
+            # parse and record the version of semgrep cli
+            version = out.split(" ")[0]
+            results.ini_writer.append("analyzer-version-semgrep-cli", version)
+
+            # copy semgrep rules into the chroot
+            props.copy_in_files += [SEMGREP_RULES_CACHE_DIR]
+
+            # get the results out of the chroot
+            props.copy_out_files += [SEMGREP_SCAN_OUTPUT, SEMGREP_SCAN_LOG]
+            return 0
+
+        props.pre_mock_hooks += [fetch_semgrep_rules_hook]
+
+        def scan_hook(results, mock, props):
+            # command to run semgrep scan
+            cmd = (f"{self.semgrep_bin} scan --metrics={args.semgrep_metrics} --sarif"
+                   f" --config={SEMGREP_RULES_CACHE_DIR}/rules")
+
+            # append additional options passed to the 'semgrep scan' command
+            if args.semgrep_scan_opts:
+                cmd += f" {args.semgrep_scan_opts}"
+
+            # eventually append the target directory to be scanned
+            cmd += f" --output={SEMGREP_SCAN_OUTPUT} {SEMGREP_SCAN_DIR} 2>{SEMGREP_SCAN_LOG}"
+            # run semgrep scan
+            ec = mock.exec_chroot_cmd(cmd)
+
+            # below are all possible return codes from semgrep scan
+            if ec == 123:
+                results.error("Indiscriminate errors reported on standard error.")
+            elif ec == 124:
+                results.error("Command line parsing errors.")
+            elif ec == 125:
+                results.error("Unexpected internal errors (bugs).")
+            return 0
+
+        # run semgrep scan after successful build
+        props.post_install_hooks += [scan_hook]
+
+        # convert the results into the csdiff's JSON format
+        def filter_hook(results):
+            src = results.dbgdir_raw + SEMGREP_SCAN_OUTPUT
+            if not os.path.exists(src):
+                return 0
+            dst = "%s/semgrep-scan-results.json" % results.dbgdir_uni
+            cmd = FILTER_CMD % (src, dst)
+            return results.exec_cmd(cmd, shell=True)
+
+        props.post_process_hooks += [filter_hook]