Commit Graph

1114 Commits

Author SHA1 Message Date
Dan Liew e2bcc33b50 Change `asan/TestCases/Darwin/malloc_zone-protected.cpp` to call abort so that it **always crashes**.
Summary:
This is needed because on some platforms we can't install signal
handlers and so the application just traps (i.e. crashes) rather than being intercepted
by ASan's signal handler which in the default Darwin config doesn't
exit with a crashing exit code.

rdar://problem/57984547

Reviewers: yln, kubamracek, jfb

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D71573
2019-12-16 16:37:50 -08:00
Dan Liew b9a92206b6 [Symbolizers] On Darwin compute function offset when possible.
Summary:
The sanitizer symbolizers support printing the function offset
(difference between pc and function start) of a stackframe using the
`%q` format specifier.

Unfortunately this didn't actually work because neither the atos
or dladdr symbolizer set the `AddressInfo::function_offset` field.

This patch teaches both symbolizers to try to compute the function
offset. In the case of the atos symbolizer, atos might not report the
function offset (e.g. it reports a source location instead) so in this
case it fallsback to using `dladdr()` to compute the function offset.

Two test cases are included.

rdar://problem/56695185

Reviewers: kubamracek, yln

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D69549
2019-11-19 10:04:44 -08:00
Julian Lettner b0567be2b4 [ASan] Mark test as UNSUPPORTED for iOS simulator
coverage-fork.cpp uses `fork()` which requires additional permissions
in the iOS simulator sandbox.  We cannot use `sandbox-exec` to grant
these permissions since this is a Posix (not Darwin) test.
2019-11-18 08:00:46 -08:00
Alexandre Ganea 478ad94c8e [GCOV] Skip artificial functions from being emitted
This is a patch to support  D66328, which was reverted until this lands.

Enable a compiler-rt test that used to fail previously with D66328.

Differential Revision: https://reviews.llvm.org/D67283
2019-11-15 14:23:11 -05:00
Jan Korous 99e2cba219 Reland "[compiler-rt] Fix tests after 03b84e4f6d0"
This reverts commit d6be9273c6.
2019-11-08 14:28:32 -08:00
Jeremy Morse d6be9273c6 Revert "[compiler-rt] Fix tests after 03b84e4f6d0"
This reverts commit bdeb2724f0.

(Reverting 03b84e4f6d, so this must come out as well)
2019-11-08 12:07:42 +00:00
Jan Korous bdeb2724f0 [compiler-rt] Fix tests after 03b84e4f6d
Fallout from:
[clang] Report sanitizer blacklist as a dependency in cc1

Default blacklists are now passed via -fsanitize-system-blacklist from driver to cc1.
2019-11-07 14:40:22 -08:00
Evgenii Stepanov 13e04607f7 [asan] Provide an interface to update an allocation stack trace.
Summary:
Sometimes an allocation stack trace is not very informative. Provide a
way to replace it with a stack trace of the user's choice.

Reviewers: pcc, kcc

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D69208
2019-10-31 13:54:46 -07:00
Reid Kleckner 0aaa193127 [asan] Update Windows test expectations for LLVM's MS demangler
After r375041 llvm-symbolizer uses it for demangling instead of
UnDecorateSymbolName. LLVM puts spaces after commas while Microsoft does
not.

llvm-svn: 375147
2019-10-17 17:59:11 +00:00
Julian Lettner 99c9d7bd63 Reland "[ASan] Do not misrepresent high value address dereferences as null dereferences"
Updated: Removed offending TODO comment.

Dereferences with addresses above the 48-bit hardware addressable range
produce "invalid instruction" (instead of "invalid access") hardware
exceptions (there is no hardware address decoding logic for those bits),
and the address provided by this exception is the address of the
instruction (not the faulting address).  The kernel maps the "invalid
instruction" to SEGV, but fails to provide the real fault address.

Because of this ASan lies and says that those cases are null
dereferences.  This downgrades the severity of a found bug in terms of
security.  In the ASan signal handler, we can not provide the real
faulting address, but at least we can try not to lie.

rdar://50366151

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D68676

> llvm-svn: 374265

llvm-svn: 374384
2019-10-10 17:19:58 +00:00
Russell Gallop c48e0873af Revert "[ASan] Do not misrepresent high value address dereferences as null dereferences"
As it was breaking bots running sanitizer lint check

This reverts r374265 (git b577efe456)

llvm-svn: 374308
2019-10-10 10:56:52 +00:00
Julian Lettner b577efe456 [ASan] Do not misrepresent high value address dereferences as null dereferences
Dereferences with addresses above the 48-bit hardware addressable range
produce "invalid instruction" (instead of "invalid access") hardware
exceptions (there is no hardware address decoding logic for those bits),
and the address provided by this exception is the address of the
instruction (not the faulting address).  The kernel maps the "invalid
instruction" to SEGV, but fails to provide the real fault address.

Because of this ASan lies and says that those cases are null
dereferences.  This downgrades the severity of a found bug in terms of
security.  In the ASan signal handler, we can not provide the real
faulting address, but at least we can try not to lie.

rdar://50366151

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D68676

llvm-svn: 374265
2019-10-10 00:33:04 +00:00
Kamil Rytarowski 5fe1e55d35 Avoid memory leak in ASan test
Summary:
Add missing free(3) for the malloc(3) call.

Detected on NetBSD with LSan.

Reviewers: joerg, mgorny, vitalybuka, dvyukov

Reviewed By: vitalybuka

Subscribers: llvm-commits, #sanitizers

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D67330

llvm-svn: 372460
2019-09-21 07:43:55 +00:00
Vitaly Buka d2af368aee [compiler-rt] Remove some cpplint filters
llvm-svn: 371704
2019-09-12 02:20:36 +00:00
Vitaly Buka c0fa632236 Remove NOLINTs from compiler-rt
llvm-svn: 371687
2019-09-11 23:19:48 +00:00
Vitaly Buka 48eb4a27d1 Update compiler-rt cpplint.py
adb3500107

llvm-svn: 371675
2019-09-11 21:33:06 +00:00
Kamil Rytarowski 90d2be0163 Stop marking 5 ASan tests as failing on NetBSD/i386
Unexpected Passing Tests (4):
    AddressSanitizer-i386-netbsd :: TestCases/Posix/coverage-reset.cpp
    AddressSanitizer-i386-netbsd :: TestCases/Posix/coverage.cpp
    AddressSanitizer-i386-netbsd :: TestCases/Posix/interception-in-shared-lib-test.cpp
    AddressSanitizer-i386-netbsd :: TestCases/suppressions-library.cpp

llvm-svn: 371337
2019-09-08 16:15:18 +00:00
Jonas Hahnfeld 307daa71a8 [ASan] Only run dlopen-mixed-c-cxx.c with static runtime
This is what the original bug (http://llvm.org/PR39641) and the fix
in https://reviews.llvm.org/D63877 have been about.
With the dynamic runtime the test only passes when the asan library
is linked against libstdc++: In contrast to libc++abi, it does not
implement __cxa_rethrow_primary_exception so the regex matches the
line saying that asan cannot intercept this function. Indeed, there
is no message that the runtime failed to intercept  __cxa_throw.

Differential Revision: https://reviews.llvm.org/D67298

llvm-svn: 371336
2019-09-08 16:08:54 +00:00
Alexander Richardson 83d2f0e799 Further relax checks in asan-symbolize-bad-path.cpp
It turns out that the DarwinSymbolizer does not print the "in" part for
invalid files but instead prints
#0 0xabcdabcd (.../asan-symbolize-bad-path.cpp.tmp/bad/path:i386+0x1234)
This tests is only checking that asan_symbolize.py doesn't hang or crash,
so further relax the checks to ensure that the test passes on macOS.

llvm-svn: 370243
2019-08-28 18:37:53 +00:00
Alexander Richardson 79f3459deb Fix asan-symbolize-bad-path.cpp on Darwin
I accidentally made the CHECK line stricter when committing D65322.
While it happens to work for Linux and FreeBSD, it broke on Darwin.
This commit restores the previous behaviour.

llvm-svn: 370110
2019-08-27 21:10:47 +00:00
Alexander Richardson 23a12fc3ac Relax test introduced in D65322
It is possible that addr2line returns a valid function and file name for
the passed address on some build configuations.
The test is only checking that asan_symbolize doesn't assert any more when
passed a valid file with an invalid address so there is no need to check
that it can't find a valid function name.
This should fix http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux

llvm-svn: 370021
2019-08-27 06:50:36 +00:00
Alexander Richardson e320db434e [asan_symbolize] Avoid blocking when llvm-symbolizer is installed as addr2line
Summary:
Currently, llvm-symbolizer will print -1 when presented with -1 and not
print a second line. In that case we will block for ever trying to read
the file name. This also happens for non-existent files, in which case GNU
addr2line exits immediate, but llvm-symbolizer does not (see
https://llvm.org/PR42754). While touching these lines, I also added some
more debug logging to help diagnose this and potential future issues.

Reviewers: kcc, eugenis, glider, samsonov

Reviewed By: eugenis

Subscribers: kubamracek, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D65322

llvm-svn: 369924
2019-08-26 16:22:04 +00:00
Julian Lettner 9f985dd380 [sanitizer_common] Extend test after switch to posix_spawn
llvm-svn: 369311
2019-08-19 23:47:35 +00:00
Julian Lettner 399408a92f [sanitizer_common] Replace forkpty with posix_spawn on Darwin
On Darwin, we currently use forkpty to communicate with the "atos"
symbolizer. There are several problems that fork[pty] has, e.g. that
after fork, interceptors are still active and this sometimes causes
crashes or hangs. This is especially problematic for TSan, which uses
interceptors for OS-provided locks and mutexes, and even Libc functions
use those.

This patch replaces forkpty with posix_spawn on Darwin. Since
posix_spawn doesn't fork (at least on Darwin), the interceptors are not
a problem. Another benefit is that we'll handle post-fork failures (e.g.
sandbox disallows "exec") gracefully now.

Related revisions and previous attempts that were blocked by or had to
be revered due to test failures:
https://reviews.llvm.org/D48451
https://reviews.llvm.org/D40032

Reviewed By: kubamracek

Differential Revision: https://reviews.llvm.org/D65253

llvm-svn: 368947
2019-08-15 00:18:55 +00:00
Dan Liew c3b93bed29 [asan_symbolize] Fix bug where the frame counter was not incremented.
Summary:
This bug occurred when a plug-in requested that a binary not be
symbolized while the script is trying to symbolize a stack frame. In
this case `self.frame_no` would not be incremented. This would cause
subsequent stack frames that are symbolized to be incorrectly numbered.

To fix this `get_symbolized_lines()` has been modified to take an
argument that indicates whether the stack frame counter should
incremented. In `process_line_posix()` `get_symbolized_lines(None, ...)`
is now used in in the case where we don't want to symbolize a line so
that we can keep the frame counter increment in a single function.

A test case is included. The test uses a dummy plugin that always asks
`asan_symbolize.py` script to not symbolize the first binary that the
script asks about. Prior to the patch this would cause the output to
script to look something like

```
  #0 0x0
  #0 0x0 in do_access
  #1 0x0 in main
```

This is the second attempt at landing this patch. The first (r368373)
failed due to failing some android bots and so was reverted in r368472.
The new test is now disabled for Android. It turns out that the patch
also fails for iOS too so it is also disabled for that family of
platforms too.

rdar://problem/49476995

Reviewers: kubamracek, yln, samsonov, dvyukov, vitalybuka

Subscribers: #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D65495

llvm-svn: 368603
2019-08-12 18:51:25 +00:00
Mitch Phillips cace571c91 Revert "[asan_symbolize] Fix bug where the frame counter was not incremented."
This reverts commit 52a36fae2a.

This commit broke the sanitizer_android buildbot. See comments at
https://reviews.llvm.org/rL368373 for more details.

llvm-svn: 368472
2019-08-09 19:36:41 +00:00
Dan Liew 52a36fae2a [asan_symbolize] Fix bug where the frame counter was not incremented.
Summary:
This bug occurred when a plug-in requested that a binary not be
symbolized while the script is trying to symbolize a stack frame. In
this case `self.frame_no` would not be incremented. This would cause
subsequent stack frames that are symbolized to be incorrectly numbered.

To fix this `get_symbolized_lines()` has been modified to take an
argument that indicates whether the stack frame counter should
incremented. In `process_line_posix()` `get_symbolized_lines(None, ...)`
is now used in in the case where we don't want to symbolize a line so
that we can keep the frame counter increment in a single function.

A test case is included. The test uses a dummy plugin that always asks
`asan_symbolize.py` script to not symbolize the first binary that the
script asks about. Prior to the patch this would cause the output to
script to look something like

```
  #0 0x0
  #0 0x0 in do_access
  #1 0x0 in main
```

rdar://problem/49476995

Reviewers: kubamracek, yln, samsonov, dvyukov, vitalybuka

Subscribers: #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D65495

llvm-svn: 368373
2019-08-09 00:52:07 +00:00
Nico Weber 673dc3d4a0 compiler-rt: Rename cc files below test/asan to cpp
See r367803 and similar other changes.

llvm-svn: 367887
2019-08-05 16:48:12 +00:00
Nico Weber 74989aff53 compiler-rt: Rename cc files below test/sanitizer_common to cpp
See r367803 and similar other changes.

llvm-svn: 367863
2019-08-05 13:57:03 +00:00
Nico Weber 217222abea compiler-rt: Rename .cc file in lib/asan to .cpp
Like r367463, but for asan.

llvm-svn: 367558
2019-08-01 13:43:28 +00:00
Alexander Richardson a4ea27de92 [Sanitizer][ASAN][MSAN] Fix infinite recursion on FreeBSD
Summary:
MSAN was broken on FreeBSD by https://reviews.llvm.org/D55703: after this
change accesses to the key variable call __tls_get_addr, which is
intercepted. The interceptor then calls GetCurrentThread which calls
MsanTSDGet which again calls __tls_get_addr, etc...
Using the default implementation in the SANITIZER_FREEBSD case fixes MSAN
for me.

I then applied the same change to ASAN (introduced in https://reviews.llvm.org/D55596)
but that did not work yet. In the ASAN case, we get infinite recursion
again during initialization, this time because calling pthread_key_create() early on
results in infinite recursion. pthread_key_create() calls sysctlbyname()
which is intercepted but COMMON_INTERCEPTOR_NOTHING_IS_INITIALIZED returns
true, so the interceptor calls internal_sysctlbyname() which then ends up
calling the interceptor again. I fixed this issue by using dlsym() to get
the libc version of sysctlbyname() instead.

This fixes https://llvm.org/PR40761

Reviewers: vitalybuka, krytarowski, devnexen, dim, bsdjhb, #sanitizers, MaskRay

Reviewed By: MaskRay

Subscribers: MaskRay, emaste, kubamracek, jfb, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D65221

llvm-svn: 367442
2019-07-31 16:31:55 +00:00
Rainer Orth 58aa6a87a6 [ASan][test] XFAIL AddressSanitizer-*-sunos :: TestCases/intercept-rethrow-exception.cc on Solaris
AddressSanitizer-*-sunos :: TestCases/intercept-rethrow-exception.cc currently FAILs
on Solaris.  This happens because std::rethrow_exception cannot be intercepted, as
detailed in Bug 42703.

To account for this and reduce testsuite noise, this patch XFAILs the test.

Tested on x86_64-pc-solaris2.11.

Differential Revision: https://reviews.llvm.org/D65056

llvm-svn: 367293
2019-07-30 07:59:43 +00:00
Lei Huang 686cee0945 [NFC][ASAN] Add brackets around not command
Under certain execution conditions, the `not` command binds to the command the
output is piped to rather than the command piping the output. In this case, that
flips the return code of the FileCheck invocation, causing a failure when
FileCheck succeeds.

llvm-svn: 366805
2019-07-23 13:10:29 +00:00
Serge Guelton a30a4a35ec Fix asan infinite loop on undefined symbol
Fix llvm#39641

Recommit of r366413

Differential Revision: https://reviews.llvm.org/D63877

> llvm-svn: 366632

llvm-svn: 366638
2019-07-20 17:44:30 +00:00
Serge Guelton 7a3d4c15a7 Revert "Fix asan infinite loop on undefined symbol"
This reverts commit cbd28cd05b.

Buildbot fail: http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/22434/steps/64-bit%20check-asan-dynamic/

llvm-svn: 366634
2019-07-20 13:00:12 +00:00
Serge Guelton cbd28cd05b Fix asan infinite loop on undefined symbol
Fix llvm#39641

Recommit of r366413

Differential Revision: https://reviews.llvm.org/D63877

llvm-svn: 366632
2019-07-20 12:01:18 +00:00
Matthew Voss 407e837540 Revert "Fix asan infinite loop on undefined symbol"
This reverts commit 8e46275488.

This was failing on sanitizer-x86_64-linux and our internal CI.

llvm-svn: 366618
2019-07-19 21:41:07 +00:00
Serge Guelton 8e46275488 Fix asan infinite loop on undefined symbol
Fix llvm#39641

Recommit of r366413

Differential Revision: https://reviews.llvm.org/D63877

llvm-svn: 366588
2019-07-19 15:20:36 +00:00
Matthew Voss 892758a526 [compiler-rt] Complete revert of r366413
Incomplete revert. Mea culpa. This test is failing on sanitizer-x86_64-linux
and our internal CI.

llvm-svn: 366482
2019-07-18 18:39:06 +00:00
Serge Guelton ec2a7c463e Restrict asan + dlopen testcase to x86
llvm-svn: 366436
2019-07-18 13:47:28 +00:00
Serge Guelton 6a61bea4d6 Relax regexp to detect failed interception by asan
This should fix failed detection on aarch64/ppc64/thumbv8...

llvm-svn: 366432
2019-07-18 13:13:29 +00:00
Serge Guelton 63719119c7 Fix asan infinite loop on undefined symbol
Fix llvm#39641

Differential Revision: https://reviews.llvm.org/D63877

llvm-svn: 366413
2019-07-18 08:09:31 +00:00
Nico Weber e837847ec6 Change another test I missed in r365724
llvm-svn: 365725
2019-07-11 01:21:17 +00:00
Nico Weber da233838c9 clang-cl: Remove -O0 option
cl.exe doesn't understand it; there's /Od instead. See also the review
thread for r229575.

Update lots of compiler-rt tests to use -Od instead of -O0.
Ran `rg -l 'clang_cl.*O0' compiler-rt/test/ | xargs sed -i -c 's/-O0/-Od/'`

Differential Revision: https://reviews.llvm.org/D64506

llvm-svn: 365724
2019-07-11 01:18:05 +00:00
Matthew G McGovern 4e636156ef [sanitizers][windows] FIX: Rtl-Heap Interception and tests
- Adds interceptors for Rtl[Allocate|Free|Size|ReAllocate]Heap
   - Adds unit tests for the new interceptors and expands HeapAlloc
     tests to demonstrate new functionality.
   Reviewed as D62927
   - adds fixes for ~win and x64 tests

> llvm-svn: 365381

llvm-svn: 365424
2019-07-09 01:55:11 +00:00
Matthew G McGovern 848a19e4eb [sanitizers][windows] Rtl-Heap Interception and tests
- Adds interceptors for Rtl[Allocate|Free|Size|ReAllocate]Heap
   - Adds unit tests for the new interceptors and expands HeapAlloc
     tests to demonstrate new functionality.
   Reviewed as D62927

llvm-svn: 365422
2019-07-09 01:47:08 +00:00
JF Bastien c5630ac641 Revert "[sanitizers][windows] Rtl-Heap Interception and tests"
Causes build failure on clang-ppc64be-linux-lnt:

compiler-rt/lib/asan/asan_malloc_win.cc:23:2: error: #error "Missing arch or unsupported platform for Windows."
 #error "Missing arch or unsupported platform for Windows."
  ^~~~~
compiler-rt/lib/asan/asan_malloc_win.cc:25:10: fatal error: heapapi.h: No such file or directory
 #include <heapapi.h>
          ^~~~~~~~~~~
compilation terminated.
[39/1151] Building CXX object projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_debugging.cc.o
[40/1151] Building CXX object projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o
FAILED: projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o
/usr/bin/c++  -D_DEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -Iprojects/compiler-rt/lib/asan -Icompiler-rt/lib/asan -Iinclude -I/home/buildbots/ppc64be-clang-lnt-test/clang-ppc64be-lnt/llvm/include -Icompiler-rt/lib/asan/.. -fPIC -fvisibility-inlines-hidden -Werror=date-time -std=c++11 -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-maybe-uninitialized -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wno-comment -fdiagnostics-color -ffunction-sections -fdata-sections -Wall -std=c++11 -Wno-unused-parameter -O2    -UNDEBUG  -m64 -fPIC -fno-builtin -fno-exceptions -fomit-frame-pointer -funwind-tables -fno-stack-protector -fvisibility=hidden -fno-lto -O3 -g -Wno-variadic-macros -Wno-non-virtual-dtor -fno-rtti -MD -MT projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o -MF projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o.d -o projects/compiler-rt/lib/asan/CMakeFiles/RTAsan.powerpc64.dir/asan_malloc_win.cc.o -c compiler-rt/lib/asan/asan_malloc_win.cc
compiler-rt/lib/asan/asan_malloc_win.cc:23:2: error: #error "Missing arch or unsupported platform for Windows."
 #error "Missing arch or unsupported platform for Windows."
  ^~~~~
compiler-rt/lib/asan/asan_malloc_win.cc:25:10: fatal error: heapapi.h: No such file or directory
 #include <heapapi.h>
          ^~~~~~~~~~~

llvm-svn: 365384
2019-07-08 20:21:09 +00:00
Matthew G McGovern c9fa99d066 [sanitizers][windows] Rtl-Heap Interception and tests
- Adds interceptors for Rtl[Allocate|Free|Size|ReAllocate]Heap
   - Adds unit tests for the new interceptors and expands HeapAlloc
     tests to demonstrate new functionality.
   Reviewed as D62927

llvm-svn: 365381
2019-07-08 19:58:50 +00:00
Reid Kleckner 8007ff1ab1 [compiler-rt] Rename lit.*.cfg.* -> lit.*.cfg.py.*
These lit configuration files are really Python source code. Using the
.py file extension helps editors and tools use the correct language
mode. LLVM and Clang already use this convention for lit configuration,
this change simply applies it to all of compiler-rt.

Reviewers: vitalybuka, dberris

Differential Revision: https://reviews.llvm.org/D63658

llvm-svn: 364591
2019-06-27 20:56:04 +00:00
Dan Liew 9216358c21 Disable recently added Darwin symbolization tests for iOS.
These tests won't necessarily work because the reported modules paths
from the device don't match what's on the host and so offline
symbolization fails.

llvm-svn: 363641
2019-06-18 01:38:03 +00:00