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// Copyright 2020 The gVisor Authors.
//
// 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 <linux/capability.h>
#include <sys/socket.h>
#include "gtest/gtest.h"
#include "test/syscalls/linux/iptables.h"
#include "test/syscalls/linux/socket_test_util.h"
#include "test/util/capability_util.h"
#include "test/util/file_descriptor.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
constexpr char kNatTablename[] = "nat";
constexpr char kErrorTarget[] = "ERROR";
constexpr size_t kEmptyStandardEntrySize =
sizeof(struct ip6t_entry) + sizeof(struct xt_standard_target);
constexpr size_t kEmptyErrorEntrySize =
sizeof(struct ip6t_entry) + sizeof(struct xt_error_target);
TEST(IP6TablesBasic, FailSockoptNonRaw) {
// Even if the user has CAP_NET_RAW, they shouldn't be able to use the
// ip6tables sockopts with a non-raw socket.
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW)));
int sock;
ASSERT_THAT(sock = socket(AF_INET6, SOCK_DGRAM, 0), SyscallSucceeds());
struct ipt_getinfo info = {};
snprintf(info.name, XT_TABLE_MAXNAMELEN, "%s", kNatTablename);
socklen_t info_size = sizeof(info);
EXPECT_THAT(getsockopt(sock, SOL_IPV6, IP6T_SO_GET_INFO, &info, &info_size),
SyscallFailsWithErrno(ENOPROTOOPT));
EXPECT_THAT(close(sock), SyscallSucceeds());
}
TEST(IP6TablesBasic, GetInfoErrorPrecedence) {
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW)));
int sock;
ASSERT_THAT(sock = socket(AF_INET6, SOCK_DGRAM, 0), SyscallSucceeds());
// When using the wrong type of socket and a too-short optlen, we should get
// EINVAL.
struct ipt_getinfo info = {};
snprintf(info.name, XT_TABLE_MAXNAMELEN, "%s", kNatTablename);
socklen_t info_size = sizeof(info) - 1;
EXPECT_THAT(getsockopt(sock, SOL_IPV6, IP6T_SO_GET_INFO, &info, &info_size),
SyscallFailsWithErrno(EINVAL));
}
TEST(IP6TablesBasic, GetEntriesErrorPrecedence) {
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW)));
int sock;
ASSERT_THAT(sock = socket(AF_INET6, SOCK_DGRAM, 0), SyscallSucceeds());
// When using the wrong type of socket and a too-short optlen, we should get
// EINVAL.
struct ip6t_get_entries entries = {};
socklen_t entries_size = sizeof(struct ip6t_get_entries) - 1;
snprintf(entries.name, XT_TABLE_MAXNAMELEN, "%s", kNatTablename);
EXPECT_THAT(
getsockopt(sock, SOL_IPV6, IP6T_SO_GET_ENTRIES, &entries, &entries_size),
SyscallFailsWithErrno(EINVAL));
}
TEST(IP6TablesBasic, GetRevision) {
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW)));
int sock;
ASSERT_THAT(sock = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW),
SyscallSucceeds());
struct xt_get_revision rev = {
.name = "REDIRECT",
.revision = 0,
};
socklen_t rev_len = sizeof(rev);
// Revision 0 exists.
EXPECT_THAT(
getsockopt(sock, SOL_IPV6, IP6T_SO_GET_REVISION_TARGET, &rev, &rev_len),
SyscallSucceeds());
EXPECT_EQ(rev.revision, 0);
// Revisions > 0 don't exist.
rev.revision = 1;
EXPECT_THAT(
getsockopt(sock, SOL_IPV6, IP6T_SO_GET_REVISION_TARGET, &rev, &rev_len),
SyscallFailsWithErrno(EPROTONOSUPPORT));
}
// This tests the initial state of a machine with empty ip6tables via
// getsockopt(IP6T_SO_GET_INFO). We don't have a guarantee that the iptables are
// empty when running in native, but we can test that gVisor has the same
// initial state that a newly-booted Linux machine would have.
TEST(IP6TablesTest, InitialInfo) {
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW)));
FileDescriptor sock =
ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_RAW));
// Get info via sockopt.
struct ipt_getinfo info = {};
snprintf(info.name, XT_TABLE_MAXNAMELEN, "%s", kNatTablename);
socklen_t info_size = sizeof(info);
ASSERT_THAT(
getsockopt(sock.get(), SOL_IPV6, IP6T_SO_GET_INFO, &info, &info_size),
SyscallSucceeds());
// The nat table supports PREROUTING, and OUTPUT.
unsigned int valid_hooks =
(1 << NF_IP6_PRE_ROUTING) | (1 << NF_IP6_LOCAL_OUT) |
(1 << NF_IP6_POST_ROUTING) | (1 << NF_IP6_LOCAL_IN);
EXPECT_EQ(info.valid_hooks, valid_hooks);
// Each chain consists of an empty entry with a standard target..
EXPECT_EQ(info.hook_entry[NF_IP6_PRE_ROUTING], 0);
EXPECT_EQ(info.hook_entry[NF_IP6_LOCAL_IN], kEmptyStandardEntrySize);
EXPECT_EQ(info.hook_entry[NF_IP6_LOCAL_OUT], kEmptyStandardEntrySize * 2);
EXPECT_EQ(info.hook_entry[NF_IP6_POST_ROUTING], kEmptyStandardEntrySize * 3);
// The underflow points are the same as the entry points.
EXPECT_EQ(info.underflow[NF_IP6_PRE_ROUTING], 0);
EXPECT_EQ(info.underflow[NF_IP6_LOCAL_IN], kEmptyStandardEntrySize);
EXPECT_EQ(info.underflow[NF_IP6_LOCAL_OUT], kEmptyStandardEntrySize * 2);
EXPECT_EQ(info.underflow[NF_IP6_POST_ROUTING], kEmptyStandardEntrySize * 3);
// One entry for each chain, plus an error entry at the end.
EXPECT_EQ(info.num_entries, 5);
EXPECT_EQ(info.size, 4 * kEmptyStandardEntrySize + kEmptyErrorEntrySize);
EXPECT_EQ(strcmp(info.name, kNatTablename), 0);
}
// This tests the initial state of a machine with empty ip6tables via
// getsockopt(IP6T_SO_GET_ENTRIES). We don't have a guarantee that the iptables
// are empty when running in native, but we can test that gVisor has the same
// initial state that a newly-booted Linux machine would have.
TEST(IP6TablesTest, InitialEntries) {
SKIP_IF(!ASSERT_NO_ERRNO_AND_VALUE(HaveCapability(CAP_NET_RAW)));
FileDescriptor sock =
ASSERT_NO_ERRNO_AND_VALUE(Socket(AF_INET6, SOCK_RAW, IPPROTO_RAW));
// Get info via sockopt.
struct ipt_getinfo info = {};
snprintf(info.name, XT_TABLE_MAXNAMELEN, "%s", kNatTablename);
socklen_t info_size = sizeof(info);
ASSERT_THAT(
getsockopt(sock.get(), SOL_IPV6, IP6T_SO_GET_INFO, &info, &info_size),
SyscallSucceeds());
// Use info to get entries.
socklen_t entries_size = sizeof(struct ip6t_get_entries) + info.size;
struct ip6t_get_entries* entries =
static_cast<struct ip6t_get_entries*>(malloc(entries_size));
snprintf(entries->name, XT_TABLE_MAXNAMELEN, "%s", kNatTablename);
entries->size = info.size;
ASSERT_THAT(getsockopt(sock.get(), SOL_IPV6, IP6T_SO_GET_ENTRIES, entries,
&entries_size),
SyscallSucceeds());
// Verify the name and size.
ASSERT_EQ(info.size, entries->size);
ASSERT_EQ(strcmp(entries->name, kNatTablename), 0);
// Verify that the entrytable is 4 entries with accept targets and no matches
// followed by a single error target.
size_t entry_offset = 0;
while (entry_offset < entries->size) {
struct ip6t_entry* entry = reinterpret_cast<struct ip6t_entry*>(
reinterpret_cast<char*>(entries->entrytable) + entry_offset);
// ipv6 should be zeroed.
struct ip6t_ip6 zeroed = {};
ASSERT_EQ(memcmp(static_cast<void*>(&zeroed),
static_cast<void*>(&entry->ipv6), sizeof(zeroed)),
0);
// target_offset should be zero.
EXPECT_EQ(entry->target_offset, sizeof(ip6t_entry));
if (entry_offset < kEmptyStandardEntrySize * 4) {
// The first 4 entries are standard targets
struct xt_standard_target* target =
reinterpret_cast<struct xt_standard_target*>(entry->elems);
EXPECT_EQ(entry->next_offset, kEmptyStandardEntrySize);
EXPECT_EQ(target->target.u.user.target_size, sizeof(*target));
EXPECT_EQ(strcmp(target->target.u.user.name, ""), 0);
EXPECT_EQ(target->target.u.user.revision, 0);
// This is what's returned for an accept verdict. I don't know why.
EXPECT_EQ(target->verdict, -NF_ACCEPT - 1);
} else {
// The last entry is an error target
struct xt_error_target* target =
reinterpret_cast<struct xt_error_target*>(entry->elems);
EXPECT_EQ(entry->next_offset, kEmptyErrorEntrySize);
EXPECT_EQ(target->target.u.user.target_size, sizeof(*target));
EXPECT_EQ(strcmp(target->target.u.user.name, kErrorTarget), 0);
EXPECT_EQ(target->target.u.user.revision, 0);
EXPECT_EQ(strcmp(target->errorname, kErrorTarget), 0);
}
entry_offset += entry->next_offset;
break;
}
free(entries);
}
} // namespace
} // namespace testing
} // namespace gvisor
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