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Unified Diff: sandbox/linux/seccomp-bpf/sandbox_bpf.cc

Issue 66723007: Make sandbox/linux/seccomp-bpf/ follow the style guide. (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: (empty) rebase Created 7 years, 1 month ago
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Index: sandbox/linux/seccomp-bpf/sandbox_bpf.cc
diff --git a/sandbox/linux/seccomp-bpf/sandbox_bpf.cc b/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
index 07de144c5afdd4e41ed2ecd312c692e39ba073e8..49fdd86d4f4f1497b937219e535c82ef69d1ea28 100644
--- a/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
+++ b/sandbox/linux/seccomp-bpf/sandbox_bpf.cc
@@ -38,23 +38,28 @@ namespace {
const int kExpectedExitCode = 100;
-template<class T> int popcount(T x);
-template<> int popcount<unsigned int>(unsigned int x) {
+template <class T>
+int popcount(T x);
+template <>
+int popcount<unsigned int>(unsigned int x) {
return __builtin_popcount(x);
}
-template<> int popcount<unsigned long>(unsigned long x) {
+template <>
+int popcount<unsigned long>(unsigned long x) {
return __builtin_popcountl(x);
}
-template<> int popcount<unsigned long long>(unsigned long long x) {
+template <>
+int popcount<unsigned long long>(unsigned long long x) {
return __builtin_popcountll(x);
}
void WriteFailedStderrSetupMessage(int out_fd) {
const char* error_string = strerror(errno);
- static const char msg[] = "You have reproduced a puzzling issue.\n"
- "Please, report to crbug.com/152530!\n"
- "Failed to set up stderr: ";
- if (HANDLE_EINTR(write(out_fd, msg, sizeof(msg)-1)) > 0 && error_string &&
+ static const char msg[] =
+ "You have reproduced a puzzling issue.\n"
+ "Please, report to crbug.com/152530!\n"
+ "Failed to set up stderr: ";
+ if (HANDLE_EINTR(write(out_fd, msg, sizeof(msg) - 1)) > 0 && error_string &&
HANDLE_EINTR(write(out_fd, error_string, strlen(error_string))) > 0 &&
HANDLE_EINTR(write(out_fd, "\n", 1))) {
}
@@ -62,18 +67,18 @@ void WriteFailedStderrSetupMessage(int out_fd) {
// We define a really simple sandbox policy. It is just good enough for us
// to tell that the sandbox has actually been activated.
-ErrorCode ProbeEvaluator(Sandbox *, int sysnum, void *) __attribute__((const));
-ErrorCode ProbeEvaluator(Sandbox *, int sysnum, void *) {
+ErrorCode ProbeEvaluator(Sandbox*, int sysnum, void*) __attribute__((const));
+ErrorCode ProbeEvaluator(Sandbox*, int sysnum, void*) {
switch (sysnum) {
- case __NR_getpid:
- // Return EPERM so that we can check that the filter actually ran.
- return ErrorCode(EPERM);
- case __NR_exit_group:
- // Allow exit() with a non-default return code.
- return ErrorCode(ErrorCode::ERR_ALLOWED);
- default:
- // Make everything else fail in an easily recognizable way.
- return ErrorCode(EINVAL);
+ case __NR_getpid:
+ // Return EPERM so that we can check that the filter actually ran.
+ return ErrorCode(EPERM);
+ case __NR_exit_group:
+ // Allow exit() with a non-default return code.
+ return ErrorCode(ErrorCode::ERR_ALLOWED);
+ default:
+ // Make everything else fail in an easily recognizable way.
+ return ErrorCode(EINVAL);
}
}
@@ -83,7 +88,7 @@ void ProbeProcess(void) {
}
}
-ErrorCode AllowAllEvaluator(Sandbox *, int sysnum, void *) {
+ErrorCode AllowAllEvaluator(Sandbox*, int sysnum, void*) {
if (!Sandbox::IsValidSyscallNumber(sysnum)) {
return ErrorCode(ENOSYS);
}
@@ -109,12 +114,11 @@ bool IsSingleThreaded(int proc_fd) {
struct stat sb;
int task = -1;
- if ((task = openat(proc_fd, "self/task", O_RDONLY|O_DIRECTORY)) < 0 ||
- fstat(task, &sb) != 0 ||
- sb.st_nlink != 3 ||
- HANDLE_EINTR(close(task))) {
+ if ((task = openat(proc_fd, "self/task", O_RDONLY | O_DIRECTORY)) < 0 ||
+ fstat(task, &sb) != 0 || sb.st_nlink != 3 || HANDLE_EINTR(close(task))) {
if (task >= 0) {
- if (HANDLE_EINTR(close(task))) { }
+ if (HANDLE_EINTR(close(task))) {
+ }
}
return false;
}
@@ -130,14 +134,13 @@ bool IsDenied(const ErrorCode& code) {
// Function that can be passed as a callback function to CodeGen::Traverse().
// Checks whether the "insn" returns an UnsafeTrap() ErrorCode. If so, it
// sets the "bool" variable pointed to by "aux".
-void CheckForUnsafeErrorCodes(Instruction *insn, void *aux) {
- bool *is_unsafe = static_cast<bool *>(aux);
+void CheckForUnsafeErrorCodes(Instruction* insn, void* aux) {
+ bool* is_unsafe = static_cast<bool*>(aux);
if (!*is_unsafe) {
- if (BPF_CLASS(insn->code) == BPF_RET &&
- insn->k > SECCOMP_RET_TRAP &&
+ if (BPF_CLASS(insn->code) == BPF_RET && insn->k > SECCOMP_RET_TRAP &&
insn->k - SECCOMP_RET_TRAP <= SECCOMP_RET_DATA) {
const ErrorCode& err =
- Trap::ErrorCodeFromTrapId(insn->k & SECCOMP_RET_DATA);
+ Trap::ErrorCodeFromTrapId(insn->k & SECCOMP_RET_DATA);
if (err.error_type() != ErrorCode::ET_INVALID && !err.safe()) {
*is_unsafe = true;
}
@@ -147,7 +150,7 @@ void CheckForUnsafeErrorCodes(Instruction *insn, void *aux) {
// A Trap() handler that returns an "errno" value. The value is encoded
// in the "aux" parameter.
-intptr_t ReturnErrno(const struct arch_seccomp_data&, void *aux) {
+intptr_t ReturnErrno(const struct arch_seccomp_data&, void* aux) {
// TrapFnc functions report error by following the native kernel convention
// of returning an exit code in the range of -1..-4096. They do not try to
// set errno themselves. The glibc wrapper that triggered the SIGSYS will
@@ -160,7 +163,7 @@ intptr_t ReturnErrno(const struct arch_seccomp_data&, void *aux) {
// Checks whether the "insn" returns an errno value from a BPF filter. If so,
// it rewrites the instruction to instead call a Trap() handler that does
// the same thing. "aux" is ignored.
-void RedirectToUserspace(Instruction *insn, void *aux) {
+void RedirectToUserspace(Instruction* insn, void* aux) {
// When inside an UnsafeTrap() callback, we want to allow all system calls.
// This means, we must conditionally disable the sandbox -- and that's not
// something that kernel-side BPF filters can do, as they cannot inspect
@@ -170,11 +173,11 @@ void RedirectToUserspace(Instruction *insn, void *aux) {
// The performance penalty for this extra round-trip to user-space is not
// actually that bad, as we only ever pay it for denied system calls; and a
// typical program has very few of these.
- Sandbox *sandbox = static_cast<Sandbox *>(aux);
+ Sandbox* sandbox = static_cast<Sandbox*>(aux);
if (BPF_CLASS(insn->code) == BPF_RET &&
(insn->k & SECCOMP_RET_ACTION) == SECCOMP_RET_ERRNO) {
insn->k = sandbox->Trap(ReturnErrno,
- reinterpret_cast<void *>(insn->k & SECCOMP_RET_DATA)).err();
+ reinterpret_cast<void*>(insn->k & SECCOMP_RET_DATA)).err();
}
}
@@ -195,8 +198,8 @@ class RedirectToUserSpacePolicyWrapper : public SandboxBpfPolicy {
ErrorCode err =
wrapped_policy_->EvaluateSyscall(sandbox_compiler, system_call_number);
if ((err.err() & SECCOMP_RET_ACTION) == SECCOMP_RET_ERRNO) {
- return sandbox_compiler->Trap(ReturnErrno,
- reinterpret_cast<void*>(err.err() & SECCOMP_RET_DATA));
+ return sandbox_compiler->Trap(
+ ReturnErrno, reinterpret_cast<void*>(err.err() & SECCOMP_RET_DATA));
}
return err;
}
@@ -206,16 +209,17 @@ class RedirectToUserSpacePolicyWrapper : public SandboxBpfPolicy {
DISALLOW_COPY_AND_ASSIGN(RedirectToUserSpacePolicyWrapper);
};
-intptr_t BpfFailure(const struct arch_seccomp_data&, void *aux) {
- SANDBOX_DIE(static_cast<char *>(aux));
+intptr_t BpfFailure(const struct arch_seccomp_data&, void* aux) {
+ SANDBOX_DIE(static_cast<char*>(aux));
}
// This class allows compatibility with the old, deprecated SetSandboxPolicy.
class CompatibilityPolicy : public SandboxBpfPolicy {
public:
CompatibilityPolicy(Sandbox::EvaluateSyscall syscall_evaluator, void* aux)
- : syscall_evaluator_(syscall_evaluator),
- aux_(aux) { DCHECK(syscall_evaluator_); }
+ : syscall_evaluator_(syscall_evaluator), aux_(aux) {
+ DCHECK(syscall_evaluator_);
+ }
virtual ErrorCode EvaluateSyscall(Sandbox* sandbox_compiler,
int system_call_number) const OVERRIDE {
@@ -234,8 +238,7 @@ Sandbox::Sandbox()
: quiet_(false),
proc_fd_(-1),
conds_(new Conds),
- sandbox_has_started_(false) {
-}
+ sandbox_has_started_(false) {}
Sandbox::~Sandbox() {
// It is generally unsafe to call any memory allocator operations or to even
@@ -258,19 +261,17 @@ bool Sandbox::IsValidSyscallNumber(int sysnum) {
return SyscallIterator::IsValid(sysnum);
}
-
bool Sandbox::RunFunctionInPolicy(void (*code_in_sandbox)(),
Sandbox::EvaluateSyscall syscall_evaluator,
- void *aux) {
+ void* aux) {
// Block all signals before forking a child process. This prevents an
// attacker from manipulating our test by sending us an unexpected signal.
sigset_t old_mask, new_mask;
- if (sigfillset(&new_mask) ||
- sigprocmask(SIG_BLOCK, &new_mask, &old_mask)) {
+ if (sigfillset(&new_mask) || sigprocmask(SIG_BLOCK, &new_mask, &old_mask)) {
SANDBOX_DIE("sigprocmask() failed");
}
int fds[2];
- if (pipe2(fds, O_NONBLOCK|O_CLOEXEC)) {
+ if (pipe2(fds, O_NONBLOCK | O_CLOEXEC)) {
SANDBOX_DIE("pipe() failed");
}
@@ -360,7 +361,7 @@ bool Sandbox::RunFunctionInPolicy(void (*code_in_sandbox)(),
char buf[4096];
ssize_t len = HANDLE_EINTR(read(fds[0], buf, sizeof(buf) - 1));
if (len > 0) {
- while (len > 1 && buf[len-1] == '\n') {
+ while (len > 1 && buf[len - 1] == '\n') {
--len;
}
buf[len] = '\000';
@@ -375,9 +376,8 @@ bool Sandbox::RunFunctionInPolicy(void (*code_in_sandbox)(),
}
bool Sandbox::KernelSupportSeccompBPF() {
- return
- RunFunctionInPolicy(ProbeProcess, ProbeEvaluator, 0) &&
- RunFunctionInPolicy(TryVsyscallProcess, AllowAllEvaluator, 0);
+ return RunFunctionInPolicy(ProbeProcess, ProbeEvaluator, 0) &&
+ RunFunctionInPolicy(TryVsyscallProcess, AllowAllEvaluator, 0);
}
Sandbox::SandboxStatus Sandbox::SupportsSeccompSandbox(int proc_fd) {
@@ -421,8 +421,8 @@ Sandbox::SandboxStatus Sandbox::SupportsSeccompSandbox(int proc_fd) {
// failures (e.g. if the current kernel lacks support for BPF filters).
sandbox.quiet_ = true;
sandbox.set_proc_fd(proc_fd);
- status_ = sandbox.KernelSupportSeccompBPF()
- ? STATUS_AVAILABLE : STATUS_UNSUPPORTED;
+ status_ = sandbox.KernelSupportSeccompBPF() ? STATUS_AVAILABLE
+ : STATUS_UNSUPPORTED;
// As we are performing our tests from a child process, the run-time
// environment that is visible to the sandbox is always guaranteed to be
@@ -435,20 +435,20 @@ Sandbox::SandboxStatus Sandbox::SupportsSeccompSandbox(int proc_fd) {
return status_;
}
-void Sandbox::set_proc_fd(int proc_fd) {
- proc_fd_ = proc_fd;
-}
+void Sandbox::set_proc_fd(int proc_fd) { proc_fd_ = proc_fd; }
void Sandbox::StartSandbox() {
if (status_ == STATUS_UNSUPPORTED || status_ == STATUS_UNAVAILABLE) {
- SANDBOX_DIE("Trying to start sandbox, even though it is known to be "
- "unavailable");
+ SANDBOX_DIE(
+ "Trying to start sandbox, even though it is known to be "
+ "unavailable");
} else if (sandbox_has_started_ || !conds_) {
- SANDBOX_DIE("Cannot repeatedly start sandbox. Create a separate Sandbox "
- "object instead.");
+ SANDBOX_DIE(
+ "Cannot repeatedly start sandbox. Create a separate Sandbox "
+ "object instead.");
}
if (proc_fd_ < 0) {
- proc_fd_ = open("/proc", O_RDONLY|O_DIRECTORY);
+ proc_fd_ = open("/proc", O_RDONLY | O_DIRECTORY);
}
if (proc_fd_ < 0) {
// For now, continue in degraded mode, if we can't access /proc.
@@ -476,11 +476,12 @@ void Sandbox::StartSandbox() {
}
void Sandbox::PolicySanityChecks(SandboxBpfPolicy* policy) {
- for (SyscallIterator iter(true); !iter.Done(); ) {
+ for (SyscallIterator iter(true); !iter.Done();) {
uint32_t sysnum = iter.Next();
if (!IsDenied(policy->EvaluateSyscall(this, sysnum))) {
- SANDBOX_DIE("Policies should deny system calls that are outside the "
- "expected range (typically MIN_SYSCALL..MAX_SYSCALL)");
+ SANDBOX_DIE(
+ "Policies should deny system calls that are outside the "
+ "expected range (typically MIN_SYSCALL..MAX_SYSCALL)");
}
}
return;
@@ -517,11 +518,11 @@ void Sandbox::InstallFilter() {
// installed the BPF filter program in the kernel. Depending on the
// system memory allocator that is in effect, these operators can result
// in system calls to things like munmap() or brk().
- Program *program = AssembleFilter(false /* force_verification */);
+ Program* program = AssembleFilter(false /* force_verification */);
struct sock_filter bpf[program->size()];
- const struct sock_fprog prog = {
- static_cast<unsigned short>(program->size()), bpf };
+ const struct sock_fprog prog = {static_cast<unsigned short>(program->size()),
+ bpf};
memcpy(bpf, &(*program)[0], sizeof(bpf));
delete program;
@@ -546,7 +547,7 @@ void Sandbox::InstallFilter() {
return;
}
-Sandbox::Program *Sandbox::AssembleFilter(bool force_verification) {
+Sandbox::Program* Sandbox::AssembleFilter(bool force_verification) {
#if !defined(NDEBUG)
force_verification = true;
#endif
@@ -555,21 +556,24 @@ Sandbox::Program *Sandbox::AssembleFilter(bool force_verification) {
DCHECK(policy_);
// Assemble the BPF filter program.
- CodeGen *gen = new CodeGen();
+ CodeGen* gen = new CodeGen();
if (!gen) {
SANDBOX_DIE("Out of memory");
}
// If the architecture doesn't match SECCOMP_ARCH, disallow the
// system call.
- Instruction *tail;
- Instruction *head =
- gen->MakeInstruction(BPF_LD+BPF_W+BPF_ABS, SECCOMP_ARCH_IDX,
- tail =
- gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K, SECCOMP_ARCH,
- NULL,
- gen->MakeInstruction(BPF_RET+BPF_K,
- Kill("Invalid audit architecture in BPF filter"))));
+ Instruction* tail;
+ Instruction* head = gen->MakeInstruction(
+ BPF_LD + BPF_W + BPF_ABS,
+ SECCOMP_ARCH_IDX,
+ tail = gen->MakeInstruction(
+ BPF_JMP + BPF_JEQ + BPF_K,
+ SECCOMP_ARCH,
+ NULL,
+ gen->MakeInstruction(
+ BPF_RET + BPF_K,
+ Kill("Invalid audit architecture in BPF filter"))));
bool has_unsafe_traps = false;
{
@@ -579,8 +583,8 @@ Sandbox::Program *Sandbox::AssembleFilter(bool force_verification) {
FindRanges(&ranges);
// Compile the system call ranges to an optimized BPF jumptable
- Instruction *jumptable =
- AssembleJumpTable(gen, ranges.begin(), ranges.end());
+ Instruction* jumptable =
+ AssembleJumpTable(gen, ranges.begin(), ranges.end());
// If there is at least one UnsafeTrap() in our program, the entire sandbox
// is unsafe. We need to modify the program so that all non-
@@ -590,8 +594,8 @@ Sandbox::Program *Sandbox::AssembleFilter(bool force_verification) {
gen->Traverse(jumptable, CheckForUnsafeErrorCodes, &has_unsafe_traps);
// Grab the system call number, so that we can implement jump tables.
- Instruction *load_nr =
- gen->MakeInstruction(BPF_LD+BPF_W+BPF_ABS, SECCOMP_NR_IDX);
+ Instruction* load_nr =
+ gen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS, SECCOMP_NR_IDX);
// If our BPF program has unsafe jumps, enable support for them. This
// test happens very early in the BPF filter program. Even before we
@@ -602,25 +606,29 @@ Sandbox::Program *Sandbox::AssembleFilter(bool force_verification) {
// is actually requested by the sandbox policy.
if (has_unsafe_traps) {
if (SandboxSyscall(-1) == -1 && errno == ENOSYS) {
- SANDBOX_DIE("Support for UnsafeTrap() has not yet been ported to this "
- "architecture");
+ SANDBOX_DIE(
+ "Support for UnsafeTrap() has not yet been ported to this "
+ "architecture");
}
- if (!policy_->EvaluateSyscall(this, __NR_rt_sigprocmask).
- Equals(ErrorCode(ErrorCode::ERR_ALLOWED)) ||
- !policy_->EvaluateSyscall(this, __NR_rt_sigreturn).
- Equals(ErrorCode(ErrorCode::ERR_ALLOWED))
+ if (!policy_->EvaluateSyscall(this, __NR_rt_sigprocmask)
+ .Equals(ErrorCode(ErrorCode::ERR_ALLOWED)) ||
+ !policy_->EvaluateSyscall(this, __NR_rt_sigreturn)
+ .Equals(ErrorCode(ErrorCode::ERR_ALLOWED))
#if defined(__NR_sigprocmask)
- || !policy_->EvaluateSyscall(this, __NR_sigprocmask).
- Equals(ErrorCode(ErrorCode::ERR_ALLOWED))
+ ||
+ !policy_->EvaluateSyscall(this, __NR_sigprocmask)
+ .Equals(ErrorCode(ErrorCode::ERR_ALLOWED))
#endif
#if defined(__NR_sigreturn)
- || !policy_->EvaluateSyscall(this, __NR_sigreturn).
- Equals(ErrorCode(ErrorCode::ERR_ALLOWED))
+ ||
+ !policy_->EvaluateSyscall(this, __NR_sigreturn)
+ .Equals(ErrorCode(ErrorCode::ERR_ALLOWED))
#endif
) {
- SANDBOX_DIE("Invalid seccomp policy; if using UnsafeTrap(), you must "
- "unconditionally allow sigreturn() and sigprocmask()");
+ SANDBOX_DIE(
+ "Invalid seccomp policy; if using UnsafeTrap(), you must "
+ "unconditionally allow sigreturn() and sigprocmask()");
}
if (!Trap::EnableUnsafeTrapsInSigSysHandler()) {
@@ -636,49 +644,58 @@ Sandbox::Program *Sandbox::AssembleFilter(bool force_verification) {
// Allow system calls, if they originate from our magic return address
// (which we can query by calling SandboxSyscall(-1)).
uintptr_t syscall_entry_point =
- static_cast<uintptr_t>(SandboxSyscall(-1));
+ static_cast<uintptr_t>(SandboxSyscall(-1));
uint32_t low = static_cast<uint32_t>(syscall_entry_point);
#if __SIZEOF_POINTER__ > 4
- uint32_t hi = static_cast<uint32_t>(syscall_entry_point >> 32);
+ uint32_t hi = static_cast<uint32_t>(syscall_entry_point >> 32);
#endif
// BPF cannot do native 64bit comparisons. On 64bit architectures, we
// have to compare both 32bit halves of the instruction pointer. If they
// match what we expect, we return ERR_ALLOWED. If either or both don't
// match, we continue evalutating the rest of the sandbox policy.
- Instruction *escape_hatch =
- gen->MakeInstruction(BPF_LD+BPF_W+BPF_ABS, SECCOMP_IP_LSB_IDX,
- gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K, low,
+ Instruction* escape_hatch = gen->MakeInstruction(
+ BPF_LD + BPF_W + BPF_ABS,
+ SECCOMP_IP_LSB_IDX,
+ gen->MakeInstruction(
+ BPF_JMP + BPF_JEQ + BPF_K,
+ low,
#if __SIZEOF_POINTER__ > 4
- gen->MakeInstruction(BPF_LD+BPF_W+BPF_ABS, SECCOMP_IP_MSB_IDX,
- gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K, hi,
+ gen->MakeInstruction(
+ BPF_LD + BPF_W + BPF_ABS,
+ SECCOMP_IP_MSB_IDX,
+ gen->MakeInstruction(
+ BPF_JMP + BPF_JEQ + BPF_K,
+ hi,
#endif
- gen->MakeInstruction(BPF_RET+BPF_K, ErrorCode(ErrorCode::ERR_ALLOWED)),
+ gen->MakeInstruction(BPF_RET + BPF_K,
+ ErrorCode(ErrorCode::ERR_ALLOWED)),
#if __SIZEOF_POINTER__ > 4
- load_nr)),
+ load_nr)),
#endif
- load_nr));
+ load_nr));
gen->JoinInstructions(tail, escape_hatch);
} else {
gen->JoinInstructions(tail, load_nr);
}
tail = load_nr;
- // On Intel architectures, verify that system call numbers are in the
- // expected number range. The older i386 and x86-64 APIs clear bit 30
- // on all system calls. The newer x32 API always sets bit 30.
+// On Intel architectures, verify that system call numbers are in the
+// expected number range. The older i386 and x86-64 APIs clear bit 30
+// on all system calls. The newer x32 API always sets bit 30.
#if defined(__i386__) || defined(__x86_64__)
- Instruction *invalidX32 =
- gen->MakeInstruction(BPF_RET+BPF_K,
- Kill("Illegal mixing of system call ABIs").err_);
- Instruction *checkX32 =
+ Instruction* invalidX32 = gen->MakeInstruction(
+ BPF_RET + BPF_K, Kill("Illegal mixing of system call ABIs").err_);
+ Instruction* checkX32 =
#if defined(__x86_64__) && defined(__ILP32__)
- gen->MakeInstruction(BPF_JMP+BPF_JSET+BPF_K, 0x40000000, 0, invalidX32);
+ gen->MakeInstruction(
+ BPF_JMP + BPF_JSET + BPF_K, 0x40000000, 0, invalidX32);
#else
- gen->MakeInstruction(BPF_JMP+BPF_JSET+BPF_K, 0x40000000, invalidX32, 0);
+ gen->MakeInstruction(
+ BPF_JMP + BPF_JSET + BPF_K, 0x40000000, invalidX32, 0);
#endif
- gen->JoinInstructions(tail, checkX32);
- tail = checkX32;
+ gen->JoinInstructions(tail, checkX32);
+ tail = checkX32;
#endif
// Append jump table to our pre-amble
@@ -686,7 +703,7 @@ Sandbox::Program *Sandbox::AssembleFilter(bool force_verification) {
}
// Turn the DAG into a vector of instructions.
- Program *program = new Program();
+ Program* program = new Program();
gen->Compile(head, program);
delete gen;
@@ -712,17 +729,16 @@ void Sandbox::VerifyProgram(const Program& program, bool has_unsafe_traps) {
new RedirectToUserSpacePolicyWrapper(policy_.get()));
const char* err = NULL;
- if (!Verifier::VerifyBPF(
- this,
- program,
- has_unsafe_traps ? *redirected_policy : *policy_,
- &err)) {
+ if (!Verifier::VerifyBPF(this,
+ program,
+ has_unsafe_traps ? *redirected_policy : *policy_,
+ &err)) {
CodeGen::PrintProgram(program);
SANDBOX_DIE(err);
}
}
-void Sandbox::FindRanges(Ranges *ranges) {
+void Sandbox::FindRanges(Ranges* ranges) {
// Please note that "struct seccomp_data" defines system calls as a signed
// int32_t, but BPF instructions always operate on unsigned quantities. We
// deal with this disparity by enumerating from MIN_SYSCALL to MAX_SYSCALL,
@@ -732,9 +748,9 @@ void Sandbox::FindRanges(Ranges *ranges) {
ErrorCode old_err = policy_->EvaluateSyscall(this, old_sysnum);
ErrorCode invalid_err = policy_->EvaluateSyscall(this, MIN_SYSCALL - 1);
- for (SyscallIterator iter(false); !iter.Done(); ) {
+ for (SyscallIterator iter(false); !iter.Done();) {
uint32_t sysnum = iter.Next();
- ErrorCode err = policy_->EvaluateSyscall(this, static_cast<int>(sysnum));
+ ErrorCode err = policy_->EvaluateSyscall(this, static_cast<int>(sysnum));
if (!iter.IsValid(sysnum) && !invalid_err.Equals(err)) {
// A proper sandbox policy should always treat system calls outside of
// the range MIN_SYSCALL..MAX_SYSCALL (i.e. anything that returns
@@ -745,12 +761,12 @@ void Sandbox::FindRanges(Ranges *ranges) {
if (!err.Equals(old_err) || iter.Done()) {
ranges->push_back(Range(old_sysnum, sysnum - 1, old_err));
old_sysnum = sysnum;
- old_err = err;
+ old_err = err;
}
}
}
-Instruction *Sandbox::AssembleJumpTable(CodeGen *gen,
+Instruction* Sandbox::AssembleJumpTable(CodeGen* gen,
Ranges::const_iterator start,
Ranges::const_iterator stop) {
// We convert the list of system call ranges into jump table that performs
@@ -769,166 +785,170 @@ Instruction *Sandbox::AssembleJumpTable(CodeGen *gen,
// We compare our system call number against the lowest valid system call
// number in this range object. If our number is lower, it is outside of
// this range object. If it is greater or equal, it might be inside.
- Ranges::const_iterator mid = start + (stop - start)/2;
+ Ranges::const_iterator mid = start + (stop - start) / 2;
// Sub-divide the list of ranges and continue recursively.
- Instruction *jf = AssembleJumpTable(gen, start, mid);
- Instruction *jt = AssembleJumpTable(gen, mid, stop);
- return gen->MakeInstruction(BPF_JMP+BPF_JGE+BPF_K, mid->from, jt, jf);
+ Instruction* jf = AssembleJumpTable(gen, start, mid);
+ Instruction* jt = AssembleJumpTable(gen, mid, stop);
+ return gen->MakeInstruction(BPF_JMP + BPF_JGE + BPF_K, mid->from, jt, jf);
}
-Instruction *Sandbox::RetExpression(CodeGen *gen, const ErrorCode& err) {
+Instruction* Sandbox::RetExpression(CodeGen* gen, const ErrorCode& err) {
if (err.error_type_ == ErrorCode::ET_COND) {
return CondExpression(gen, err);
} else {
- return gen->MakeInstruction(BPF_RET+BPF_K, err);
+ return gen->MakeInstruction(BPF_RET + BPF_K, err);
}
}
-Instruction *Sandbox::CondExpression(CodeGen *gen, const ErrorCode& cond) {
+Instruction* Sandbox::CondExpression(CodeGen* gen, const ErrorCode& cond) {
// We can only inspect the six system call arguments that are passed in
// CPU registers.
if (cond.argno_ < 0 || cond.argno_ >= 6) {
- SANDBOX_DIE("Internal compiler error; invalid argument number "
- "encountered");
+ SANDBOX_DIE(
+ "Internal compiler error; invalid argument number "
+ "encountered");
}
// BPF programs operate on 32bit entities. Load both halfs of the 64bit
// system call argument and then generate suitable conditional statements.
- Instruction *msb_head =
- gen->MakeInstruction(BPF_LD+BPF_W+BPF_ABS,
- SECCOMP_ARG_MSB_IDX(cond.argno_));
- Instruction *msb_tail = msb_head;
- Instruction *lsb_head =
- gen->MakeInstruction(BPF_LD+BPF_W+BPF_ABS,
- SECCOMP_ARG_LSB_IDX(cond.argno_));
- Instruction *lsb_tail = lsb_head;
+ Instruction* msb_head = gen->MakeInstruction(
+ BPF_LD + BPF_W + BPF_ABS, SECCOMP_ARG_MSB_IDX(cond.argno_));
+ Instruction* msb_tail = msb_head;
+ Instruction* lsb_head = gen->MakeInstruction(
+ BPF_LD + BPF_W + BPF_ABS, SECCOMP_ARG_LSB_IDX(cond.argno_));
+ Instruction* lsb_tail = lsb_head;
// Emit a suitable comparison statement.
switch (cond.op_) {
- case ErrorCode::OP_EQUAL:
- // Compare the least significant bits for equality
- lsb_tail = gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K,
- static_cast<uint32_t>(cond.value_),
- RetExpression(gen, *cond.passed_),
- RetExpression(gen, *cond.failed_));
- gen->JoinInstructions(lsb_head, lsb_tail);
-
- // If we are looking at a 64bit argument, we need to also compare the
- // most significant bits.
- if (cond.width_ == ErrorCode::TP_64BIT) {
- msb_tail = gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K,
- static_cast<uint32_t>(cond.value_ >> 32),
- lsb_head,
+ case ErrorCode::OP_EQUAL:
+ // Compare the least significant bits for equality
+ lsb_tail = gen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K,
+ static_cast<uint32_t>(cond.value_),
+ RetExpression(gen, *cond.passed_),
RetExpression(gen, *cond.failed_));
- gen->JoinInstructions(msb_head, msb_tail);
- }
- break;
- case ErrorCode::OP_HAS_ALL_BITS:
- // Check the bits in the LSB half of the system call argument. Our
- // OP_HAS_ALL_BITS operator passes, iff all of the bits are set. This is
- // different from the kernel's BPF_JSET operation which passes, if any of
- // the bits are set.
- // Of course, if there is only a single set bit (or none at all), then
- // things get easier.
- {
- uint32_t lsb_bits = static_cast<uint32_t>(cond.value_);
- int lsb_bit_count = popcount(lsb_bits);
- if (lsb_bit_count == 0) {
- // No bits are set in the LSB half. The test will always pass.
- lsb_head = RetExpression(gen, *cond.passed_);
- lsb_tail = NULL;
- } else if (lsb_bit_count == 1) {
- // Exactly one bit is set in the LSB half. We can use the BPF_JSET
- // operator.
- lsb_tail = gen->MakeInstruction(BPF_JMP+BPF_JSET+BPF_K,
- lsb_bits,
- RetExpression(gen, *cond.passed_),
- RetExpression(gen, *cond.failed_));
- gen->JoinInstructions(lsb_head, lsb_tail);
- } else {
- // More than one bit is set in the LSB half. We need to combine
- // BPF_AND and BPF_JEQ to test whether all of these bits are in fact
- // set in the system call argument.
- gen->JoinInstructions(lsb_head,
- gen->MakeInstruction(BPF_ALU+BPF_AND+BPF_K,
- lsb_bits,
- lsb_tail = gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K,
+ gen->JoinInstructions(lsb_head, lsb_tail);
+
+ // If we are looking at a 64bit argument, we need to also compare the
+ // most significant bits.
+ if (cond.width_ == ErrorCode::TP_64BIT) {
+ msb_tail =
+ gen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K,
+ static_cast<uint32_t>(cond.value_ >> 32),
+ lsb_head,
+ RetExpression(gen, *cond.failed_));
+ gen->JoinInstructions(msb_head, msb_tail);
+ }
+ break;
+ case ErrorCode::OP_HAS_ALL_BITS:
+ // Check the bits in the LSB half of the system call argument. Our
+ // OP_HAS_ALL_BITS operator passes, iff all of the bits are set. This is
+ // different from the kernel's BPF_JSET operation which passes, if any of
+ // the bits are set.
+ // Of course, if there is only a single set bit (or none at all), then
+ // things get easier.
+ {
+ uint32_t lsb_bits = static_cast<uint32_t>(cond.value_);
+ int lsb_bit_count = popcount(lsb_bits);
+ if (lsb_bit_count == 0) {
+ // No bits are set in the LSB half. The test will always pass.
+ lsb_head = RetExpression(gen, *cond.passed_);
+ lsb_tail = NULL;
+ } else if (lsb_bit_count == 1) {
+ // Exactly one bit is set in the LSB half. We can use the BPF_JSET
+ // operator.
+ lsb_tail = gen->MakeInstruction(BPF_JMP + BPF_JSET + BPF_K,
lsb_bits,
RetExpression(gen, *cond.passed_),
- RetExpression(gen, *cond.failed_))));
+ RetExpression(gen, *cond.failed_));
+ gen->JoinInstructions(lsb_head, lsb_tail);
+ } else {
+ // More than one bit is set in the LSB half. We need to combine
+ // BPF_AND and BPF_JEQ to test whether all of these bits are in fact
+ // set in the system call argument.
+ gen->JoinInstructions(
+ lsb_head,
+ gen->MakeInstruction(BPF_ALU + BPF_AND + BPF_K,
+ lsb_bits,
+ lsb_tail = gen->MakeInstruction(
+ BPF_JMP + BPF_JEQ + BPF_K,
+ lsb_bits,
+ RetExpression(gen, *cond.passed_),
+ RetExpression(gen, *cond.failed_))));
+ }
}
- }
- // If we are looking at a 64bit argument, we need to also check the bits
- // in the MSB half of the system call argument.
- if (cond.width_ == ErrorCode::TP_64BIT) {
- uint32_t msb_bits = static_cast<uint32_t>(cond.value_ >> 32);
- int msb_bit_count = popcount(msb_bits);
- if (msb_bit_count == 0) {
- // No bits are set in the MSB half. The test will always pass.
- msb_head = lsb_head;
- } else if (msb_bit_count == 1) {
- // Exactly one bit is set in the MSB half. We can use the BPF_JSET
- // operator.
- msb_tail = gen->MakeInstruction(BPF_JMP+BPF_JSET+BPF_K,
- msb_bits,
- lsb_head,
- RetExpression(gen, *cond.failed_));
- gen->JoinInstructions(msb_head, msb_tail);
- } else {
- // More than one bit is set in the MSB half. We need to combine
- // BPF_AND and BPF_JEQ to test whether all of these bits are in fact
- // set in the system call argument.
- gen->JoinInstructions(msb_head,
- gen->MakeInstruction(BPF_ALU+BPF_AND+BPF_K,
- msb_bits,
- gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K,
- msb_bits,
- lsb_head,
- RetExpression(gen, *cond.failed_))));
+ // If we are looking at a 64bit argument, we need to also check the bits
+ // in the MSB half of the system call argument.
+ if (cond.width_ == ErrorCode::TP_64BIT) {
+ uint32_t msb_bits = static_cast<uint32_t>(cond.value_ >> 32);
+ int msb_bit_count = popcount(msb_bits);
+ if (msb_bit_count == 0) {
+ // No bits are set in the MSB half. The test will always pass.
+ msb_head = lsb_head;
+ } else if (msb_bit_count == 1) {
+ // Exactly one bit is set in the MSB half. We can use the BPF_JSET
+ // operator.
+ msb_tail = gen->MakeInstruction(BPF_JMP + BPF_JSET + BPF_K,
+ msb_bits,
+ lsb_head,
+ RetExpression(gen, *cond.failed_));
+ gen->JoinInstructions(msb_head, msb_tail);
+ } else {
+ // More than one bit is set in the MSB half. We need to combine
+ // BPF_AND and BPF_JEQ to test whether all of these bits are in fact
+ // set in the system call argument.
+ gen->JoinInstructions(
+ msb_head,
+ gen->MakeInstruction(
+ BPF_ALU + BPF_AND + BPF_K,
+ msb_bits,
+ gen->MakeInstruction(BPF_JMP + BPF_JEQ + BPF_K,
+ msb_bits,
+ lsb_head,
+ RetExpression(gen, *cond.failed_))));
+ }
}
- }
- break;
- case ErrorCode::OP_HAS_ANY_BITS:
- // Check the bits in the LSB half of the system call argument. Our
- // OP_HAS_ANY_BITS operator passes, iff any of the bits are set. This maps
- // nicely to the kernel's BPF_JSET operation.
- {
- uint32_t lsb_bits = static_cast<uint32_t>(cond.value_);
- if (!lsb_bits) {
- // No bits are set in the LSB half. The test will always fail.
- lsb_head = RetExpression(gen, *cond.failed_);
- lsb_tail = NULL;
- } else {
- lsb_tail = gen->MakeInstruction(BPF_JMP+BPF_JSET+BPF_K,
- lsb_bits,
- RetExpression(gen, *cond.passed_),
- RetExpression(gen, *cond.failed_));
- gen->JoinInstructions(lsb_head, lsb_tail);
+ break;
+ case ErrorCode::OP_HAS_ANY_BITS:
+ // Check the bits in the LSB half of the system call argument. Our
+ // OP_HAS_ANY_BITS operator passes, iff any of the bits are set. This maps
+ // nicely to the kernel's BPF_JSET operation.
+ {
+ uint32_t lsb_bits = static_cast<uint32_t>(cond.value_);
+ if (!lsb_bits) {
+ // No bits are set in the LSB half. The test will always fail.
+ lsb_head = RetExpression(gen, *cond.failed_);
+ lsb_tail = NULL;
+ } else {
+ lsb_tail = gen->MakeInstruction(BPF_JMP + BPF_JSET + BPF_K,
+ lsb_bits,
+ RetExpression(gen, *cond.passed_),
+ RetExpression(gen, *cond.failed_));
+ gen->JoinInstructions(lsb_head, lsb_tail);
+ }
}
- }
- // If we are looking at a 64bit argument, we need to also check the bits
- // in the MSB half of the system call argument.
- if (cond.width_ == ErrorCode::TP_64BIT) {
- uint32_t msb_bits = static_cast<uint32_t>(cond.value_ >> 32);
- if (!msb_bits) {
- // No bits are set in the MSB half. The test will always fail.
- msb_head = lsb_head;
- } else {
- msb_tail = gen->MakeInstruction(BPF_JMP+BPF_JSET+BPF_K,
- msb_bits,
- RetExpression(gen, *cond.passed_),
- lsb_head);
- gen->JoinInstructions(msb_head, msb_tail);
+ // If we are looking at a 64bit argument, we need to also check the bits
+ // in the MSB half of the system call argument.
+ if (cond.width_ == ErrorCode::TP_64BIT) {
+ uint32_t msb_bits = static_cast<uint32_t>(cond.value_ >> 32);
+ if (!msb_bits) {
+ // No bits are set in the MSB half. The test will always fail.
+ msb_head = lsb_head;
+ } else {
+ msb_tail = gen->MakeInstruction(BPF_JMP + BPF_JSET + BPF_K,
+ msb_bits,
+ RetExpression(gen, *cond.passed_),
+ lsb_head);
+ gen->JoinInstructions(msb_head, msb_tail);
+ }
}
- }
- break;
- default:
- // TODO(markus): Need to add support for OP_GREATER
- SANDBOX_DIE("Not implemented");
- break;
+ break;
+ default:
+ // TODO(markus): Need to add support for OP_GREATER
+ SANDBOX_DIE("Not implemented");
+ break;
}
// Ensure that we never pass a 64bit value, when we only expect a 32bit
@@ -937,26 +957,28 @@ Instruction *Sandbox::CondExpression(CodeGen *gen, const ErrorCode& cond) {
// LSB has been sign-extended into the MSB.
if (cond.width_ == ErrorCode::TP_32BIT) {
if (cond.value_ >> 32) {
- SANDBOX_DIE("Invalid comparison of a 32bit system call argument "
- "against a 64bit constant; this test is always false.");
+ SANDBOX_DIE(
+ "Invalid comparison of a 32bit system call argument "
+ "against a 64bit constant; this test is always false.");
}
- Instruction *invalid_64bit = RetExpression(gen, Unexpected64bitArgument());
- #if __SIZEOF_POINTER__ > 4
- invalid_64bit =
- gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K, 0xFFFFFFFF,
- gen->MakeInstruction(BPF_LD+BPF_W+BPF_ABS,
- SECCOMP_ARG_LSB_IDX(cond.argno_),
- gen->MakeInstruction(BPF_JMP+BPF_JGE+BPF_K, 0x80000000,
- lsb_head,
- invalid_64bit)),
- invalid_64bit);
- #endif
+ Instruction* invalid_64bit = RetExpression(gen, Unexpected64bitArgument());
+#if __SIZEOF_POINTER__ > 4
+ invalid_64bit = gen->MakeInstruction(
+ BPF_JMP + BPF_JEQ + BPF_K,
+ 0xFFFFFFFF,
+ gen->MakeInstruction(BPF_LD + BPF_W + BPF_ABS,
+ SECCOMP_ARG_LSB_IDX(cond.argno_),
+ gen->MakeInstruction(BPF_JMP + BPF_JGE + BPF_K,
+ 0x80000000,
+ lsb_head,
+ invalid_64bit)),
+ invalid_64bit);
+#endif
gen->JoinInstructions(
- msb_tail,
- gen->MakeInstruction(BPF_JMP+BPF_JEQ+BPF_K, 0,
- lsb_head,
- invalid_64bit));
+ msb_tail,
+ gen->MakeInstruction(
+ BPF_JMP + BPF_JEQ + BPF_K, 0, lsb_head, invalid_64bit));
}
return msb_head;
@@ -966,11 +988,11 @@ ErrorCode Sandbox::Unexpected64bitArgument() {
return Kill("Unexpected 64bit argument detected");
}
-ErrorCode Sandbox::Trap(Trap::TrapFnc fnc, const void *aux) {
+ErrorCode Sandbox::Trap(Trap::TrapFnc fnc, const void* aux) {
return Trap::MakeTrap(fnc, aux, true /* Safe Trap */);
}
-ErrorCode Sandbox::UnsafeTrap(Trap::TrapFnc fnc, const void *aux) {
+ErrorCode Sandbox::UnsafeTrap(Trap::TrapFnc fnc, const void* aux) {
return Trap::MakeTrap(fnc, aux, false /* Unsafe Trap */);
}
@@ -984,16 +1006,22 @@ intptr_t Sandbox::ForwardSyscall(const struct arch_seccomp_data& args) {
static_cast<intptr_t>(args.args[5]));
}
-ErrorCode Sandbox::Cond(int argno, ErrorCode::ArgType width,
- ErrorCode::Operation op, uint64_t value,
- const ErrorCode& passed, const ErrorCode& failed) {
- return ErrorCode(argno, width, op, value,
+ErrorCode Sandbox::Cond(int argno,
+ ErrorCode::ArgType width,
+ ErrorCode::Operation op,
+ uint64_t value,
+ const ErrorCode& passed,
+ const ErrorCode& failed) {
+ return ErrorCode(argno,
+ width,
+ op,
+ value,
&*conds_->insert(passed).first,
&*conds_->insert(failed).first);
}
-ErrorCode Sandbox::Kill(const char *msg) {
- return Trap(BpfFailure, const_cast<char *>(msg));
+ErrorCode Sandbox::Kill(const char* msg) {
+ return Trap(BpfFailure, const_cast<char*>(msg));
}
Sandbox::SandboxStatus Sandbox::status_ = STATUS_UNKNOWN;
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