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// Copyright 2018 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 <sys/prctl.h>
#include <sys/ptrace.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <string>
#include "gtest/gtest.h"
#include "absl/flags/flag.h"
#include "test/util/capability_util.h"
#include "test/util/cleanup.h"
#include "test/util/multiprocess_util.h"
#include "test/util/posix_error.h"
#include "test/util/test_util.h"
#include "test/util/thread_util.h"
ABSL_FLAG(bool, prctl_no_new_privs_test_child, false,
"If true, exit with the return value of prctl(PR_GET_NO_NEW_PRIVS) "
"plus an offset (see test source).");
namespace gvisor {
namespace testing {
namespace {
#ifndef SUID_DUMP_DISABLE
#define SUID_DUMP_DISABLE 0
#endif /* SUID_DUMP_DISABLE */
#ifndef SUID_DUMP_USER
#define SUID_DUMP_USER 1
#endif /* SUID_DUMP_USER */
#ifndef SUID_DUMP_ROOT
#define SUID_DUMP_ROOT 2
#endif /* SUID_DUMP_ROOT */
TEST(PrctlTest, NameInitialized) {
const size_t name_length = 20;
char name[name_length] = {};
ASSERT_THAT(prctl(PR_GET_NAME, name), SyscallSucceeds());
ASSERT_NE(std::string(name), "");
}
TEST(PrctlTest, SetNameLongName) {
const size_t name_length = 20;
const std::string long_name(name_length, 'A');
ASSERT_THAT(prctl(PR_SET_NAME, long_name.c_str()), SyscallSucceeds());
char truncated_name[name_length] = {};
ASSERT_THAT(prctl(PR_GET_NAME, truncated_name), SyscallSucceeds());
const size_t truncated_length = 15;
ASSERT_EQ(long_name.substr(0, truncated_length), std::string(truncated_name));
}
TEST(PrctlTest, ChildProcessName) {
constexpr size_t kMaxNameLength = 15;
char parent_name[kMaxNameLength + 1] = {};
memset(parent_name, 'a', kMaxNameLength);
ASSERT_THAT(prctl(PR_SET_NAME, parent_name), SyscallSucceeds());
pid_t child_pid = fork();
TEST_PCHECK(child_pid >= 0);
if (child_pid == 0) {
char child_name[kMaxNameLength + 1] = {};
TEST_PCHECK(prctl(PR_GET_NAME, child_name) >= 0);
TEST_CHECK(memcmp(parent_name, child_name, sizeof(parent_name)) == 0);
_exit(0);
}
int status;
ASSERT_THAT(waitpid(child_pid, &status, 0),
SyscallSucceedsWithValue(child_pid));
EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0)
<< "status =" << status;
}
// Offset added to exit code from test child to distinguish from other abnormal
// exits.
constexpr int kPrctlNoNewPrivsTestChildExitBase = 100;
TEST(PrctlTest, NoNewPrivsPreservedAcrossCloneForkAndExecve) {
// Check if no_new_privs is already set. If it is, we can still test that it's
// preserved across clone/fork/execve, but we also expect it to still be set
// at the end of the test. Otherwise, call prctl(PR_SET_NO_NEW_PRIVS) so as
// not to contaminate the original thread.
int no_new_privs;
ASSERT_THAT(no_new_privs = prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0),
SyscallSucceeds());
ScopedThread thread = ScopedThread([] {
ASSERT_THAT(prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0), SyscallSucceeds());
EXPECT_THAT(prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0),
SyscallSucceedsWithValue(1));
ScopedThread threadInner = ScopedThread([] {
EXPECT_THAT(prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0),
SyscallSucceedsWithValue(1));
// Note that these ASSERT_*s failing will only return from this thread,
// but this is the intended behavior.
pid_t child_pid = -1;
int execve_errno = 0;
auto cleanup = ASSERT_NO_ERRNO_AND_VALUE(
ForkAndExec("/proc/self/exe",
{"/proc/self/exe", "--prctl_no_new_privs_test_child"}, {},
nullptr, &child_pid, &execve_errno));
ASSERT_GT(child_pid, 0);
ASSERT_EQ(execve_errno, 0);
int status = 0;
ASSERT_THAT(RetryEINTR(waitpid)(child_pid, &status, 0),
SyscallSucceeds());
ASSERT_TRUE(WIFEXITED(status));
ASSERT_EQ(WEXITSTATUS(status), kPrctlNoNewPrivsTestChildExitBase + 1);
EXPECT_THAT(prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0),
SyscallSucceedsWithValue(1));
});
threadInner.Join();
EXPECT_THAT(prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0),
SyscallSucceedsWithValue(1));
});
thread.Join();
EXPECT_THAT(prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0),
SyscallSucceedsWithValue(no_new_privs));
}
TEST(PrctlTest, PDeathSig) {
pid_t child_pid;
// Make the new process' parent a separate thread since the parent death
// signal fires when the parent *thread* exits.
ScopedThread thread = ScopedThread([&] {
child_pid = fork();
TEST_CHECK(child_pid >= 0);
if (child_pid == 0) {
// In child process.
TEST_CHECK(prctl(PR_SET_PDEATHSIG, SIGKILL) >= 0);
int signo;
TEST_CHECK(prctl(PR_GET_PDEATHSIG, &signo) >= 0);
TEST_CHECK(signo == SIGKILL);
// Enable tracing, then raise SIGSTOP and expect our parent to suppress
// it.
TEST_CHECK(ptrace(PTRACE_TRACEME, 0, 0, 0) >= 0);
TEST_CHECK(raise(SIGSTOP) == 0);
// Sleep until killed by our parent death signal. sleep(3) is
// async-signal-safe, absl::SleepFor isn't.
while (true) {
sleep(10);
}
}
// In parent process.
// Wait for the child to send itself SIGSTOP and enter signal-delivery-stop.
int status;
ASSERT_THAT(waitpid(child_pid, &status, 0),
SyscallSucceedsWithValue(child_pid));
EXPECT_TRUE(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP)
<< "status = " << status;
// Suppress the SIGSTOP and detach from the child.
ASSERT_THAT(ptrace(PTRACE_DETACH, child_pid, 0, 0), SyscallSucceeds());
});
thread.Join();
// The child should have been killed by its parent death SIGKILL.
int status;
ASSERT_THAT(waitpid(child_pid, &status, 0),
SyscallSucceedsWithValue(child_pid));
EXPECT_TRUE(WIFSIGNALED(status) && WTERMSIG(status) == SIGKILL)
<< "status = " << status;
}
// This test is to validate that calling prctl with PR_SET_MM without the
// CAP_SYS_RESOURCE returns EPERM.
TEST(PrctlTest, InvalidPrSetMM) {
// Drop capability to test below.
AutoCapability cap(CAP_SYS_RESOURCE, false);
ASSERT_THAT(prctl(PR_SET_MM, 0, 0, 0, 0), SyscallFailsWithErrno(EPERM));
}
// Sanity check that dumpability is remembered.
TEST(PrctlTest, SetGetDumpability) {
int before;
ASSERT_THAT(before = prctl(PR_GET_DUMPABLE), SyscallSucceeds());
auto cleanup = Cleanup([before] {
ASSERT_THAT(prctl(PR_SET_DUMPABLE, before), SyscallSucceeds());
});
EXPECT_THAT(prctl(PR_SET_DUMPABLE, SUID_DUMP_DISABLE), SyscallSucceeds());
EXPECT_THAT(prctl(PR_GET_DUMPABLE),
SyscallSucceedsWithValue(SUID_DUMP_DISABLE));
EXPECT_THAT(prctl(PR_SET_DUMPABLE, SUID_DUMP_USER), SyscallSucceeds());
EXPECT_THAT(prctl(PR_GET_DUMPABLE), SyscallSucceedsWithValue(SUID_DUMP_USER));
}
// SUID_DUMP_ROOT cannot be set via PR_SET_DUMPABLE.
TEST(PrctlTest, RootDumpability) {
EXPECT_THAT(prctl(PR_SET_DUMPABLE, SUID_DUMP_ROOT),
SyscallFailsWithErrno(EINVAL));
}
TEST(PrctlTest, SetGetSubreaper) {
// Setting subreaper on PID 1 works vacuously because PID 1 is always a
// subreaper.
EXPECT_THAT(prctl(PR_SET_CHILD_SUBREAPER, 1), SyscallSucceeds());
}
} // namespace
} // namespace testing
} // namespace gvisor
int main(int argc, char** argv) {
gvisor::testing::TestInit(&argc, &argv);
if (absl::GetFlag(FLAGS_prctl_no_new_privs_test_child)) {
exit(gvisor::testing::kPrctlNoNewPrivsTestChildExitBase +
prctl(PR_GET_NO_NEW_PRIVS, 0, 0, 0, 0));
}
return gvisor::testing::RunAllTests();
}
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