1 files changed, 98 insertions, 0 deletions
diff --git a/tests/50-sim-hash_collision.c b/tests/50-sim-hash_collision.c
new file mode 100644
index 0000000..24eba19
--- /dev/null
+++ b/tests/50-sim-hash_collision.c
@@ -0,0 +1,98 @@
+/**
+ * Seccomp Library test program
+ *
+ * Copyright (c) 2019 Oracle and/or its affiliates.  All rights reserved.
+ * Author: Tom Hromatka <tom.hromatka@oracle.com>
+ */
+
+/*
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of version 2.1 of the GNU Lesser General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This library 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 Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, see <http://www.gnu.org/licenses>.
+ */
+
+#include <errno.h>
+#include <unistd.h>
+
+#include <seccomp.h>
+
+#include "util.h"
+
+int main(int argc, char *argv[])
+{
+	int rc;
+	struct util_options opts;
+	scmp_filter_ctx ctx = NULL;
+
+	rc = util_getopt(argc, argv, &opts);
+	if (rc < 0)
+		goto out;
+
+	rc = seccomp_api_set(1);
+	if (rc != 0)
+		return -rc;
+
+	ctx = seccomp_init(SCMP_ACT_ERRNO(100));
+	if (ctx == NULL)
+		return ENOMEM;
+
+	rc = seccomp_arch_remove(ctx, SCMP_ARCH_NATIVE);
+	if (rc != 0)
+		goto out;
+	rc = seccomp_arch_add(ctx, SCMP_ARCH_X86_64);
+	if (rc != 0)
+		goto out;
+
+	/* libseccomp utilizes a hash table to manage BPF blocks.  It
+	 * currently employs MurmurHash3 where the key is the hashed values
+	 * of the BPF instruction blocks, the accumulator start, and the
+	 * accumulator end.  Changes to the hash algorithm will likely affect
+	 * this test.
+	 */
+
+	/* The following rules were derived from an issue reported by Tor:
+	 * https://github.com/seccomp/libseccomp/issues/148
+	 *
+	 * In the steps below, syscall 1001 is configured similarly to how
+	 * Tor configured socket.  The fairly complex rules below led to
+	 * a hash collision with rt_sigaction (syscall 1000) in this test.
+	 */
+
+	rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, 1001, 3,
+			      SCMP_A0(SCMP_CMP_EQ, 1),
+			      SCMP_A1(SCMP_CMP_MASKED_EQ, 0xf, 2),
+			      SCMP_A2(SCMP_CMP_EQ, 3));
+	if (rc != 0)
+		goto out;
+	rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, 1001, 2,
+			      SCMP_A0(SCMP_CMP_EQ, 1),
+			      SCMP_A1(SCMP_CMP_MASKED_EQ, 0xf, 1));
+	if (rc != 0)
+		goto out;
+
+
+	rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, 1000, 1,
+			      SCMP_A0(SCMP_CMP_EQ, 2));
+	if (rc != 0)
+		goto out;
+	rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, 1000, 1,
+			      SCMP_A0(SCMP_CMP_EQ, 1));
+	if (rc != 0)
+		goto out;
+
+	rc = util_filter_output(&opts, ctx);
+	if (rc)
+		goto out;
+
+out:
+	seccomp_release(ctx);
+	return (rc < 0 ? -rc : rc);
+}