-------------------------------------------------------------------
Copyright (C) 2017 The Android Open Source Project
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+
+-------------------------------------------------------------------
+
+Copyright (C) 2017 The Android Open Source Project
All rights reserved.
Redistribution and use in source and binary forms, with or without
LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
LOCAL_MODULE := libseccomp_policy
LOCAL_CLANG := true
-LOCAL_SRC_FILES := arm_policy.c arm64_policy.c
+LOCAL_SRC_FILES := seccomp_policy.cpp arm_policy.cpp arm64_policy.cpp
LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)
+LOCAL_SHARED_LIBRARIES := libbase
include $(BUILD_STATIC_LIBRARY)
#include <linux/filter.h>
#include <errno.h>
-#include "seccomp_policy.h"
-const struct sock_filter arm64_filter[] = {
+#include "seccomp_bpfs.h"
+const sock_filter arm64_filter[] = {
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 5, 0, 25),
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 203, 13, 0),
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 101, 7, 0),
#include <linux/filter.h>
#include <errno.h>
-#include "seccomp_policy.h"
-const struct sock_filter arm_filter[] = {
+#include "seccomp_bpfs.h"
+const sock_filter arm_filter[] = {
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 0, 0, 125),
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 168, 63, 0),
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 77, 31, 0),
--- /dev/null
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef SECCOMP_BPFS_H
+#define SECCOMP_BPFS_H
+
+#include <stddef.h>
+#include <linux/seccomp.h>
+
+extern const struct sock_filter arm_filter[];
+extern const size_t arm_filter_size;
+extern const struct sock_filter arm64_filter[];
+extern const size_t arm64_filter_size;
+
+#endif
--- /dev/null
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vector>
+
+#include <sys/prctl.h>
+
+#include <linux/unistd.h>
+#include <linux/audit.h>
+#include <linux/filter.h>
+#include <linux/seccomp.h>
+
+#include <android-base/logging.h>
+
+#include "seccomp_policy.h"
+
+extern const struct sock_filter arm_filter[];
+extern const size_t arm_filter_size;
+extern const struct sock_filter arm64_filter[];
+extern const size_t arm64_filter_size;
+
+#define syscall_nr (offsetof(struct seccomp_data, nr))
+#define arch_nr (offsetof(struct seccomp_data, arch))
+
+typedef std::vector<sock_filter> filter;
+
+// We want to keep the below inline functions for debugging and future
+// development even though they are not all sed currently.
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunused-function"
+
+static inline void Kill(filter& f) {
+ f.push_back(BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL));
+}
+
+static inline void Trap(filter& f) {
+ f.push_back(BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRAP));
+}
+
+static inline void Error(filter& f, __u16 retcode) {
+ f.push_back(BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ERRNO + retcode));
+}
+
+inline static void Trace(filter& f) {
+ f.push_back(BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_TRACE));
+}
+
+inline static void Allow(filter& f) {
+ f.push_back(BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW));
+}
+
+#pragma clang diagnostic pop
+
+inline static void ExamineSyscall(filter& f) {
+ f.push_back(BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_nr));
+}
+
+inline static int SetValidateArchitectureJumpTarget(size_t offset, filter& f) {
+ size_t jump_length = f.size() - offset - 1;
+ auto u8_jump_length = (__u8) jump_length;
+ if (u8_jump_length != jump_length) {
+ LOG(FATAL)
+ << "Can't set jump greater than 255 - actual jump is " << jump_length;
+ return -1;
+ }
+ f[offset] = BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, AUDIT_ARCH_ARM, u8_jump_length, 0);
+ return 0;
+}
+
+inline static size_t ValidateArchitectureAndJumpIfNeeded(filter& f) {
+ f.push_back(BPF_STMT(BPF_LD|BPF_W|BPF_ABS, arch_nr));
+
+ f.push_back(BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, AUDIT_ARCH_AARCH64, 2, 0));
+ f.push_back(BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, AUDIT_ARCH_ARM, 1, 0));
+ Trap(f);
+ return f.size() - 2;
+}
+
+static bool install_filter(filter const& f) {
+ struct sock_fprog prog = {
+ static_cast<unsigned short>(f.size()),
+ const_cast<struct sock_filter*>(&f[0]),
+ };
+
+ if (prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog) < 0) {
+ PLOG(FATAL) << "Could not set seccomp filter of size " << f.size();
+ return false;
+ }
+
+ LOG(INFO) << "Global filter of size " << f.size() << " installed";
+ return true;
+}
+
+bool set_seccomp_filter() {
+ filter f;
+
+ // Note that for mixed 64/32 bit architectures, ValidateArchitecture inserts a
+ // jump that must be changed to point to the start of the 32-bit policy
+ // 32 bit syscalls will not hit the policy between here and the call to SetJump
+ auto offset_to_32bit_filter = ValidateArchitectureAndJumpIfNeeded(f);
+
+ // 64-bit filter
+ ExamineSyscall(f);
+
+ // arm64-only filter - autogenerated from bionic syscall usage
+ for (size_t i = 0; i < arm64_filter_size; ++i) {
+ f.push_back(arm64_filter[i]);
+ }
+ Trap(f);
+
+ if (SetValidateArchitectureJumpTarget(offset_to_32bit_filter, f) != 0) {
+ return -1;
+ }
+
+ // 32-bit filter
+ ExamineSyscall(f);
+
+ // arm32 filter - autogenerated from bionic syscall usage
+ for (size_t i = 0; i < arm_filter_size; ++i) {
+ f.push_back(arm_filter[i]);
+ }
+ Trap(f);
+
+ return install_filter(f);
+}
#ifndef SECCOMP_POLICY_H
#define SECCOMP_POLICY_H
-#include <stddef.h>
-#include <linux/seccomp.h>
-
-extern const struct sock_filter arm_filter[];
-extern const size_t arm_filter_size;
-extern const struct sock_filter arm64_filter[];
-extern const size_t arm64_filter_size;
+bool set_seccomp_filter();
#endif
#include <linux/filter.h>
#include <errno.h>
- #include "seccomp_policy.h"
- const struct sock_filter {architecture}_filter[] = {{
+ #include "seccomp_bpfs.h"
+ const sock_filter {architecture}_filter[] = {{
""").format(architecture=architecture)
footer = textwrap.dedent("""\
# And output policy
existing = ""
- output_path = "seccomp/{}_policy.c".format(arch)
+ output_path = "seccomp/{}_policy.cpp".format(arch)
if os.path.isfile(output_path):
existing = open(output_path).read()
if output == existing:
#include <linux/filter.h>
#include <errno.h>
- #include "seccomp_policy.h"
- const struct sock_filter arm_filter[] = {
+ #include "seccomp_bpfs.h"
+ const sock_filter arm_filter[] = {
line1
line2
};
#include <linux/filter.h>
#include <errno.h>
- #include "seccomp_policy.h"
- const struct sock_filter arm_filter[] = {
+ #include "seccomp_bpfs.h"
+ const sock_filter arm_filter[] = {
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 3, 0, 3),
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 140, 1, 0),
BPF_JUMP(BPF_JMP|BPF_JGE|BPF_K, 4, 2, 1), //read
OSDN Git Service
