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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.
// Tests to verify that the behavior of linux and gvisor matches when
// 'sysret' returns to bad (aka non-canonical) %rip or %rsp.
#include <linux/elf.h>
#include <sys/ptrace.h>
#include <sys/user.h>
#include "gtest/gtest.h"
#include "test/util/logging.h"
#include "test/util/test_util.h"
namespace gvisor {
namespace testing {
namespace {
constexpr uint64_t kNonCanonicalRip = 0xCCCC000000000000;
constexpr uint64_t kNonCanonicalRsp = 0xFFFF000000000000;
class SysretTest : public ::testing::Test {
protected:
struct user_regs_struct regs_;
struct iovec iov;
pid_t child_;
void SetUp() override {
pid_t pid = fork();
// Child.
if (pid == 0) {
TEST_PCHECK(ptrace(PTRACE_TRACEME, 0, 0, 0) == 0);
MaybeSave();
TEST_PCHECK(raise(SIGSTOP) == 0);
MaybeSave();
_exit(0);
}
// Parent.
int status;
memset(&iov, 0, sizeof(iov));
ASSERT_THAT(pid, SyscallSucceeds()); // Might still be < 0.
ASSERT_THAT(waitpid(pid, &status, 0), SyscallSucceedsWithValue(pid));
EXPECT_TRUE(WIFSTOPPED(status) && WSTOPSIG(status) == SIGSTOP);
iov.iov_base = ®s_;
iov.iov_len = sizeof(regs_);
ASSERT_THAT(ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, &iov),
SyscallSucceeds());
child_ = pid;
}
void Detach() {
ASSERT_THAT(ptrace(PTRACE_DETACH, child_, 0, 0), SyscallSucceeds());
}
void SetRip(uint64_t newrip) {
#if defined(__x86_64__)
regs_.rip = newrip;
#elif defined(__aarch64__)
regs_.pc = newrip;
#else
#error "Unknown architecture"
#endif
ASSERT_THAT(ptrace(PTRACE_SETREGSET, child_, NT_PRSTATUS, &iov),
SyscallSucceeds());
}
void SetRsp(uint64_t newrsp) {
#if defined(__x86_64__)
regs_.rsp = newrsp;
#elif defined(__aarch64__)
regs_.sp = newrsp;
#else
#error "Unknown architecture"
#endif
ASSERT_THAT(ptrace(PTRACE_SETREGSET, child_, NT_PRSTATUS, &iov),
SyscallSucceeds());
}
// Wait waits for the child pid and returns the exit status.
int Wait() {
int status;
while (true) {
int rval = wait4(child_, &status, 0, NULL);
if (rval < 0) {
return rval;
}
if (rval == child_) {
return status;
}
}
}
};
TEST_F(SysretTest, JustDetach) {
Detach();
int status = Wait();
EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0)
<< "status = " << status;
}
TEST_F(SysretTest, BadRip) {
SetRip(kNonCanonicalRip);
Detach();
int status = Wait();
EXPECT_TRUE(WIFSIGNALED(status) && WTERMSIG(status) == SIGSEGV)
<< "status = " << status;
}
TEST_F(SysretTest, BadRsp) {
SetRsp(kNonCanonicalRsp);
Detach();
int status = Wait();
#if defined(__x86_64__)
EXPECT_TRUE(WIFSIGNALED(status) && WTERMSIG(status) == SIGBUS)
<< "status = " << status;
#elif defined(__aarch64__)
EXPECT_TRUE(WIFSIGNALED(status) && WTERMSIG(status) == SIGSEGV)
<< "status = " << status;
#else
#error "Unknown architecture"
#endif
}
} // namespace
} // namespace testing
} // namespace gvisor
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