Add syscall sandboxing (seccomp-bpf)

test/config.ini.in

@@ -24,3 +24,4 @@ RPCAUTH=@abs_top_srcdir@/share/rpcauth/rpcauth.py
 @ENABLE_FUZZ_TRUE@ENABLE_FUZZ=true
 @ENABLE_ZMQ_TRUE@ENABLE_ZMQ=true
 @ENABLE_EXTERNAL_SIGNER_TRUE@ENABLE_EXTERNAL_SIGNER=true
+@ENABLE_SYSCALL_SANDBOX_TRUE@ENABLE_SYSCALL_SANDBOX=true

test/functional/feature_notifications.py

@@ -27,6 +27,9 @@ class NotificationsTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 2
         self.setup_clean_chain = True
+        # The experimental syscall sandbox feature (-sandbox) is not compatible with -alertnotify,
+        # -blocknotify or -walletnotify (which all invoke execve).
+        self.disable_syscall_sandbox = True
 
     def setup_network(self):
         self.wallet = ''.join(chr(i) for i in range(FILE_CHAR_START, FILE_CHAR_END) if chr(i) not in FILE_CHARS_DISALLOWED)

test/functional/feature_syscall_sandbox.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+# Copyright (c) 2021 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test bitcoind aborts if a disallowed syscall is used when compiled with the syscall sandbox."""
+
+from test_framework.test_framework import BitcoinTestFramework, SkipTest
+
+
+class SyscallSandboxTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+
+    def skip_test_if_missing_module(self):
+        if not self.is_syscall_sandbox_compiled():
+            raise SkipTest("bitcoind has not been built with syscall sandbox enabled.")
+        if self.options.nosandbox:
+            raise SkipTest("--nosandbox passed to test runner.")
+
+    def run_test(self):
+        disallowed_syscall_terminated_bitcoind = False
+        expected_log_entry = 'ERROR: The syscall "getgroups" (syscall number 115) is not allowed by the syscall sandbox'
+        with self.nodes[0].assert_debug_log([expected_log_entry]):
+            self.log.info("Invoking disallowed syscall")
+            try:
+                self.nodes[0].invokedisallowedsyscall()
+            except ConnectionError:
+                disallowed_syscall_terminated_bitcoind = True
+        assert disallowed_syscall_terminated_bitcoind
+        self.nodes = []
+
+
+if __name__ == "__main__":
+    SyscallSandboxTest().main()

test/functional/feature_versionbits_warning.py

@@ -28,6 +28,9 @@ class VersionBitsWarningTest(BitcoinTestFramework):
     def set_test_params(self):
         self.setup_clean_chain = True
         self.num_nodes = 1
+        # The experimental syscall sandbox feature (-sandbox) is not compatible with -alertnotify
+        # (which invokes execve).
+        self.disable_syscall_sandbox = True
 
     def setup_network(self):
         self.alert_filename = os.path.join(self.options.tmpdir, "alert.txt")

test/functional/rpc_misc.py

@@ -57,7 +57,7 @@ class RpcMiscTest(BitcoinTestFramework):
         self.log.info("test logging rpc and help")
 
         # Test logging RPC returns the expected number of logging categories.
-        assert_equal(len(node.logging()), 25)
+        assert_equal(len(node.logging()), 26)
 
         # Test toggling a logging category on/off/on with the logging RPC.
         assert_equal(node.logging()['qt'], True)

test/functional/rpc_signer.py

@@ -27,6 +27,9 @@ class RPCSignerTest(BitcoinTestFramework):
 
     def set_test_params(self):
         self.num_nodes = 4
+        # The experimental syscall sandbox feature (-sandbox) is not compatible with -signer (which
+        # invokes execve).
+        self.disable_syscall_sandbox = True
 
         self.extra_args = [
             [],

test/functional/test_framework/test_framework.py

@@ -101,6 +101,7 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
         self.supports_cli = True
         self.bind_to_localhost_only = True
         self.parse_args()
+        self.disable_syscall_sandbox = self.options.nosandbox
         self.default_wallet_name = "default_wallet" if self.options.descriptors else ""
         self.wallet_data_filename = "wallet.dat"
         # Optional list of wallet names that can be set in set_test_params to
@@ -159,6 +160,8 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
         parser = argparse.ArgumentParser(usage="%(prog)s [options]")
         parser.add_argument("--nocleanup", dest="nocleanup", default=False, action="store_true",
                             help="Leave bitcoinds and test.* datadir on exit or error")
+        parser.add_argument("--nosandbox", dest="nosandbox", default=False, action="store_true",
+                            help="Don't use the syscall sandbox")
         parser.add_argument("--noshutdown", dest="noshutdown", default=False, action="store_true",
                             help="Don't stop bitcoinds after the test execution")
         parser.add_argument("--cachedir", dest="cachedir", default=os.path.abspath(os.path.dirname(os.path.realpath(__file__)) + "/../../cache"),
@@ -468,6 +471,10 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
             extra_args = [[]] * num_nodes
         if versions is None:
             versions = [None] * num_nodes
+        if self.is_syscall_sandbox_compiled() and not self.disable_syscall_sandbox:
+            for i in range(len(extra_args)):
+                if versions[i] is None or versions[i] >= 219900:
+                    extra_args[i] = extra_args[i] + ["-sandbox=log-and-abort"]
         if binary is None:
             binary = [get_bin_from_version(v, 'bitcoind', self.options.bitcoind) for v in versions]
         if binary_cli is None:
@@ -886,3 +893,7 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
     def is_bdb_compiled(self):
         """Checks whether the wallet module was compiled with BDB support."""
         return self.config["components"].getboolean("USE_BDB")
+
+    def is_syscall_sandbox_compiled(self):
+        """Checks whether the syscall sandbox was compiled."""
+        return self.config["components"].getboolean("ENABLE_SYSCALL_SANDBOX")

test/functional/test_runner.py

@@ -170,6 +170,7 @@ BASE_SCRIPTS = [
     'rpc_users.py',
     'rpc_whitelist.py',
     'feature_proxy.py',
+    'feature_syscall_sandbox.py',
     'rpc_signrawtransaction.py --legacy-wallet',
     'rpc_signrawtransaction.py --descriptors',
     'rpc_rawtransaction.py --legacy-wallet',

test/functional/wallet_signer.py

@@ -27,6 +27,9 @@ class WalletSignerTest(BitcoinTestFramework):
 
     def set_test_params(self):
         self.num_nodes = 2
+        # The experimental syscall sandbox feature (-sandbox) is not compatible with -signer (which
+        # invokes execve).
+        self.disable_syscall_sandbox = True
 
         self.extra_args = [
             [],