// 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