[compiler-rt] r312576 - [msan] Check sigset_t and sigaction arguments.

Richard Smith via llvm-commits llvm-commits at lists.llvm.org
Tue Sep 5 17:21:36 PDT 2017


On 5 September 2017 at 14:08, Evgeniy Stepanov via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: eugenis
> Date: Tue Sep  5 14:08:56 2017
> New Revision: 312576
>
> URL: http://llvm.org/viewvc/llvm-project?rev=312576&view=rev
> Log:
> [msan] Check sigset_t and sigaction arguments.
>
> Summary:
> Check sigset_t arguments in ppoll, sig*wait*, sigprocmask
> interceptors, and the entire "struct sigaction" in sigaction. This
> can be done because sigemptyset/sigfullset are intercepted and
> signal masks should be correctly marked as initialized.
>
> Reviewers: vitalybuka
>
> Subscribers: kubamracek, llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D37367
>
> Added:
>     compiler-rt/trunk/test/msan/Linux/poll.cc
>     compiler-rt/trunk/test/msan/sigaction.cc
> Modified:
>     compiler-rt/trunk/lib/msan/msan_interceptors.cc
>     compiler-rt/trunk/lib/sanitizer_common/sanitizer_
> common_interceptors.inc
>     compiler-rt/trunk/test/msan/sigwait.cc
>
> Modified: compiler-rt/trunk/lib/msan/msan_interceptors.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/
> msan/msan_interceptors.cc?rev=312576&r1=312575&r2=312576&view=diff
> ============================================================
> ==================
> --- compiler-rt/trunk/lib/msan/msan_interceptors.cc (original)
> +++ compiler-rt/trunk/lib/msan/msan_interceptors.cc Tue Sep  5 14:08:56
> 2017
> @@ -983,11 +983,21 @@ static void SignalAction(int signo, void
>    cb(signo, si, uc);
>  }
>
> +static void read_sigaction(const __sanitizer_sigaction *act) {
> +  CHECK_UNPOISONED(&act->sa_flags, sizeof(act->sa_flags));
> +  if (act->sa_flags & __sanitizer::sa_siginfo)
> +    CHECK_UNPOISONED(&act->sigaction, sizeof(act->sigaction));
> +  else
> +    CHECK_UNPOISONED(&act->handler, sizeof(act->handler));
> +  CHECK_UNPOISONED(&act->sa_mask, sizeof(act->sa_mask));
> +}
> +
>  INTERCEPTOR(int, sigaction, int signo, const __sanitizer_sigaction *act,
>              __sanitizer_sigaction *oldact) {
>    ENSURE_MSAN_INITED();
>    // FIXME: check that *act is unpoisoned.
>

Can this FIXME be removed now?


>    // That requires intercepting all of sigemptyset, sigfillset, etc.
> +  if (act) read_sigaction(act);
>    int res;
>    if (flags()->wrap_signals) {
>      SpinMutexLock lock(&sigactions_mu);
>
> Modified: compiler-rt/trunk/lib/sanitizer_common/sanitizer_
> common_interceptors.inc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/lib/
> sanitizer_common/sanitizer_common_interceptors.inc?rev=
> 312576&r1=312575&r2=312576&view=diff
> ============================================================
> ==================
> --- compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
> (original)
> +++ compiler-rt/trunk/lib/sanitizer_common/sanitizer_common_interceptors.inc
> Tue Sep  5 14:08:56 2017
> @@ -3589,7 +3589,7 @@ INTERCEPTOR(int, ppoll, __sanitizer_poll
>    if (fds && nfds) read_pollfd(ctx, fds, nfds);
>    if (timeout_ts)
>      COMMON_INTERCEPTOR_READ_RANGE(ctx, timeout_ts, struct_timespec_sz);
> -  // FIXME: read sigmask when all of sigemptyset, etc are intercepted.
> +  if (sigmask) COMMON_INTERCEPTOR_READ_RANGE(ctx, sigmask,
> sizeof(*sigmask));
>    int res =
>        COMMON_INTERCEPTOR_BLOCK_REAL(ppoll)(fds, nfds, timeout_ts,
> sigmask);
>    if (fds && nfds) write_pollfd(ctx, fds, nfds);
> @@ -3630,7 +3630,7 @@ INTERCEPTOR(int, wordexp, char *s, __san
>  INTERCEPTOR(int, sigwait, __sanitizer_sigset_t *set, int *sig) {
>    void *ctx;
>    COMMON_INTERCEPTOR_ENTER(ctx, sigwait, set, sig);
> -  // FIXME: read sigset_t when all of sigemptyset, etc are intercepted
> +  if (set) COMMON_INTERCEPTOR_READ_RANGE(ctx, set, sizeof(*set));
>    // FIXME: under ASan the call below may write to freed memory and
> corrupt
>    // its metadata. See
>    // https://github.com/google/sanitizers/issues/321.
> @@ -3647,7 +3647,7 @@ INTERCEPTOR(int, sigwait, __sanitizer_si
>  INTERCEPTOR(int, sigwaitinfo, __sanitizer_sigset_t *set, void *info) {
>    void *ctx;
>    COMMON_INTERCEPTOR_ENTER(ctx, sigwaitinfo, set, info);
> -  // FIXME: read sigset_t when all of sigemptyset, etc are intercepted
> +  if (set) COMMON_INTERCEPTOR_READ_RANGE(ctx, set, sizeof(*set));
>    // FIXME: under ASan the call below may write to freed memory and
> corrupt
>    // its metadata. See
>    // https://github.com/google/sanitizers/issues/321.
> @@ -3666,7 +3666,7 @@ INTERCEPTOR(int, sigtimedwait, __sanitiz
>    void *ctx;
>    COMMON_INTERCEPTOR_ENTER(ctx, sigtimedwait, set, info, timeout);
>    if (timeout) COMMON_INTERCEPTOR_READ_RANGE(ctx, timeout,
> struct_timespec_sz);
> -  // FIXME: read sigset_t when all of sigemptyset, etc are intercepted
> +  if (set) COMMON_INTERCEPTOR_READ_RANGE(ctx, set, sizeof(*set));
>    // FIXME: under ASan the call below may write to freed memory and
> corrupt
>    // its metadata. See
>    // https://github.com/google/sanitizers/issues/321.
> @@ -3729,7 +3729,7 @@ INTERCEPTOR(int, sigprocmask, int how, _
>              __sanitizer_sigset_t *oldset) {
>    void *ctx;
>    COMMON_INTERCEPTOR_ENTER(ctx, sigprocmask, how, set, oldset);
> -  // FIXME: read sigset_t when all of sigemptyset, etc are intercepted
> +  if (set) COMMON_INTERCEPTOR_READ_RANGE(ctx, set, sizeof(*set));
>    // FIXME: under ASan the call below may write to freed memory and
> corrupt
>    // its metadata. See
>    // https://github.com/google/sanitizers/issues/321.
>
> Added: compiler-rt/trunk/test/msan/Linux/poll.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/
> test/msan/Linux/poll.cc?rev=312576&view=auto
> ============================================================
> ==================
> --- compiler-rt/trunk/test/msan/Linux/poll.cc (added)
> +++ compiler-rt/trunk/test/msan/Linux/poll.cc Tue Sep  5 14:08:56 2017
> @@ -0,0 +1,42 @@
> +// RUN: %clangxx_msan -O0 -std=c++11 -g %s -o %t
> +// RUN: %run %t _ 2>&1 | FileCheck %s --check-prefix=CLEAN
> +// RUN: not %run %t A 2>&1 | FileCheck %s --check-prefix=A
> +// RUN: not %run %t B 2>&1 | FileCheck %s --check-prefix=B
> +
> +#include <assert.h>
> +#include <poll.h>
> +#include <signal.h>
> +#include <stdio.h>
> +
> +#include <sanitizer/msan_interface.h>
> +
> +int main(int argc, char **argv) {
> +  char T = argv[1][0];
> +
> +  struct timespec ts;
> +  ts.tv_sec = 0;
> +  ts.tv_nsec = 1000;
> +  int res = ppoll(nullptr, 0, &ts, nullptr);
> +  assert(res == 0);
> +
> +  if (T == 'A') {
> +    __msan_poison(&ts.tv_sec, sizeof(ts.tv_sec));
> +    ppoll(nullptr, 0, &ts, nullptr);
> +    // A: use-of-uninitialized-value
> +  }
> +
> +  // A-NOT: ==1
> +  // B: ==1
> +  fprintf(stderr, "==1\n");
> +
> +  sigset_t sig;
> +  if (T != 'B')
> +    sigemptyset(&sig);
> +  ppoll(nullptr, 0, &ts, &sig);
> +  // B: use-of-uninitialized-value
> +
> +  // B-NOT: ==2
> +  // CLEAN: ==2
> +  fprintf(stderr, "==2\n");
> +  return 0;
> +}
>
> Added: compiler-rt/trunk/test/msan/sigaction.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/
> test/msan/sigaction.cc?rev=312576&view=auto
> ============================================================
> ==================
> --- compiler-rt/trunk/test/msan/sigaction.cc (added)
> +++ compiler-rt/trunk/test/msan/sigaction.cc Tue Sep  5 14:08:56 2017
> @@ -0,0 +1,47 @@
> +// RUN: %clangxx_msan -std=c++11 -O0 -g %s -o %t
> +// RUN: %run %t __
> +// RUN: not %run %t A_ 2>&1 | FileCheck %s
> +// RUN: not %run %t AH 2>&1 | FileCheck %s
> +// RUN: not %run %t B_ 2>&1 | FileCheck %s
> +// RUN: not %run %t BH 2>&1 | FileCheck %s
> +// RUN: not %run %t C_ 2>&1 | FileCheck %s
> +// RUN: not %run %t CH 2>&1 | FileCheck %s
> +
> +#include <assert.h>
> +#include <signal.h>
> +#include <string.h>
> +#include <sys/time.h>
> +#include <unistd.h>
> +
> +#include <sanitizer/msan_interface.h>
> +
> +void handler(int) {}
> +void action(int, siginfo_t *, void *) {}
> +
> +int main(int argc, char **argv) {
> +  char T = argv[1][0];
> +  char H = argv[1][1];
> +  struct sigaction sa;
> +  memset(&sa, 0, sizeof(sa));
> +  if (H == 'H') {
> +    sa.sa_handler = handler;
> +  } else {
> +    sa.sa_sigaction = action;
> +    sa.sa_flags = SA_SIGINFO;
> +  }
> +
> +  if (T == 'A') {
> +    if (H == 'H')
> +      __msan_poison(&sa.sa_handler, sizeof(sa.sa_handler));
> +    else
> +      __msan_poison(&sa.sa_sigaction, sizeof(sa.sa_sigaction));
> +  }
> +  if (T == 'B')
> +    __msan_poison(&sa.sa_flags, sizeof(sa.sa_flags));
> +  if (T == 'C')
> +    __msan_poison(&sa.sa_mask, sizeof(sa.sa_mask));
> +  // CHECK: use-of-uninitialized-value
> +  int res = sigaction(SIGUSR1, &sa, nullptr);
> +  assert(res == 0);
> +  return 0;
> +}
>
> Modified: compiler-rt/trunk/test/msan/sigwait.cc
> URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/
> test/msan/sigwait.cc?rev=312576&r1=312575&r2=312576&view=diff
> ============================================================
> ==================
> --- compiler-rt/trunk/test/msan/sigwait.cc (original)
> +++ compiler-rt/trunk/test/msan/sigwait.cc Tue Sep  5 14:08:56 2017
> @@ -1,16 +1,21 @@
>  // RUN: %clangxx_msan -std=c++11 -O0 -g %s -o %t && %run %t
> +// RUN: %clangxx_msan -DPOSITIVE -std=c++11 -O0 -g %s -o %t && not %run
> %t 2>&1 | FileCheck %s
>
>  #include <assert.h>
> -#include <sanitizer/msan_interface.h>
>  #include <signal.h>
>  #include <sys/time.h>
>  #include <unistd.h>
>
> +#include <sanitizer/msan_interface.h>
> +
>  void test_sigwait() {
>    sigset_t s;
> +#ifndef POSITIVE
>    sigemptyset(&s);
>    sigaddset(&s, SIGUSR1);
> +#endif
>    sigprocmask(SIG_BLOCK, &s, 0);
> +  // CHECK:  MemorySanitizer: use-of-uninitialized-value
>
>    if (pid_t pid = fork()) {
>      kill(pid, SIGUSR1);
>
>
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