Summary:
There's no unwinding functionality on Android that allows for line
numbers to be retrieved in-process. As a result, we can't have
this backtrace test run on Android.
Cleanup the test to use optnone functions instead, which is more stable
than line numbers anyway.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: #sanitizers, morehouse, cferris
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D76807
Summary:
Backtrace() returns the number of frames that are *available*, rather
than the number of frames stored. When we pack, we supply the number of
frames we have stored. The number of available frames can exceed the
number of stored frames, leading to stack OOB read.
Fix up this problem.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: #sanitizers, morehouse, cferris, pcc
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D76722
Summary: It complains about reaching the end of a non-void returning function.
Reviewers: eugenis, hctim, morehouse
Subscribers: #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D74578
Summary:
New shard out of the Check() function for GWP-ASan uses
android_set_abort_message. This is happily present on bionic Android,
but not Android for glibc host x86. Fix up to use the weak definition
always, so we don't have to worry.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: #sanitizers, llvm-commits, pcc, cferris
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D74142
Summary:
GWP-ASan's PRNG didn't use Initial-Exec TLS. Fix that to ensure that we don't
have infinite recursion, and also that we don't allocate a DTV on Android when
GWP-ASan is touched.
Test coverage ensuring that the sample counter is UINT32_MAX for an
uninitialised GWP-ASan is provided by gwp_asan/tests/late_init.cpp.
Reviewers: pcc, cferris
Reviewed By: pcc
Subscribers: #sanitizers, llvm-commits, rprichard, eugenis
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D74135
Summary:
Forewarning: This patch looks big in #LOC changed. I promise it's not that bad, it just moves a lot of content from one file to another. I've gone ahead and left inline comments on Phabricator for sections where this has happened.
This patch:
1. Introduces the crash handler API (crash_handler_api.h).
2. Moves information required for out-of-process crash handling into an AllocatorState. This is a trivially-copied POD struct that designed to be recovered from a deceased process, and used by the crash handler to create a GWP-ASan report (along with the other trivially-copied Metadata struct).
3. Implements the crash handler API using the AllocatorState and Metadata.
4. Adds tests for the crash handler.
5. Reimplements the (now optionally linked by the supporting allocator) in-process crash handler (i.e. the segv handler) using the new crash handler API.
6. Minor updates Scudo & Scudo Standalone to fix compatibility.
7. Changed capitalisation of errors (e.g. /s/Use after free/Use After Free).
Reviewers: cryptoad, eugenis, jfb
Reviewed By: eugenis
Subscribers: merge_guards_bot, pcc, jfb, dexonsmith, mgorny, cryptoad, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73557
Summary:
This patch allows for late initialisation of the GWP-ASan allocator. Previously, if late initialisation occurred, the sample counter was never updated, meaning we would end up having to wait for 2^32 allocations before getting a sampled allocation.
Now, we initialise the sampling mechanism in init() as well. We require init() to be called single-threaded, so this isn't a problem.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: merge_guards_bot, mgorny, #sanitizers, llvm-commits, cferris
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73896
Summary:
This is an Android-specific interface for iterating over all live
allocations in a memory range.
Reviewers: hctim, cferris
Subscribers: mgorny, mgrang, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73305
Summary:
* Implement enable() and disable() in GWP-ASan.
* Setup atfork handler.
* Improve test harness sanity and re-enable GWP-ASan in Scudo.
Scudo_standalone disables embedded GWP-ASan as necessary around fork().
Standalone GWP-ASan sets the atfork handler in init() if asked to. This
requires a working malloc(), therefore GWP-ASan initialization in Scudo
is delayed to the post-init callback.
Test harness changes are about setting up a single global instance of
the GWP-ASan allocator so that pthread_atfork() does not create
dangling pointers.
Test case shamelessly stolen from D72470.
Reviewers: cryptoad, hctim, jfb
Subscribers: mgorny, jfb, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73294
Summary:
GWP-ASan test currently fail on 32-bit platforms, as some of the pointers are
larger than `uintptr_t` on 32-bit platforms. Fix up all those instances.
Also add an uncompress varint test where the result is an underflow.
Furthermore, allow multi-init for testing. Each gtest when running
`check-gwp_asan` apparently runs in its own instance, but when integrating
these tests into Android, this behaviour isn't the same. We remove the
global multi-init check here, to allow for testing to work elsewhere, and we're
not really worried about multi-init anyway as it's part of our contract with
the allocator.
Reviewers: eugenis, vlad.tsyrklevich
Reviewed By: eugenis
Subscribers: #sanitizers, llvm-commits, pcc
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D71121
Summary:
When platforms use their own `LIKELY()` definitions, it can be quite
troublesome to ensure they don't conflict with the GWP-ASan internal
definitions. Just force the GWP_ASAN_ prefix to help this issue.
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: #sanitizers, llvm-commits, cferris, pcc
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D70683
https://bugs.llvm.org/show_bug.cgi?id=43722
GWP-ASan didn't include SANITIZER_COMMON_CFLAGS, and thus would produce
LLVM bitcode files, when compiler-rt is generally built without LTO.
Summary:
@eugenis to approve addition of //compiler-rt/tools.
@pree-jackie please confirm that this WFY.
D66494 introduced the GWP-ASan stack_trace_compressor_fuzzer. Building fuzz
targets in compiler-rt is a new affair, and has some challenges:
- If the host compiler doesn't have compiler-rt, the -fsanitize=fuzzer may not
be able to link against `libclang_rt.fuzzer*`.
- Things in compiler-rt generally aren't built when you want to build with
sanitizers using `-DLLVM_USE_SANITIZER`. This tricky to work around, so
we create the new tools directory so that we can build fuzz targets with
sanitizers. This has the added bonus of fixing the problem above as well, as
we can now just guard the fuzz target build to only be done with
`-DLLVM_USE_SANITIZE_COVERAGE=On`.
Reviewers: eugenis, pree-jackie
Reviewed By: eugenis, pree-jackie
Subscribers: dberris, mgorny, #sanitizers, llvm-commits, eugenis, pree-jackie, lebedev.ri, vitalybuka, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66776
llvm-svn: 370094
This is a fixup for r369823 which introduced the use of
VERSION_GREATER_EQUAL in the cmake config for gwp_asan.
Minimum supported version of cmake in LLVM is 3.4.3 and
VERSION_GREATER_EQUAL was not introduced until later
versions of cmake.
llvm-svn: 369891
Summary:
optional/options_parser and optional/backtrace_sanitizer_common are logically
separate components. They both use sanitizer-common to power their
functionality, but there was an unstated implicit dependency that in order for
backtrace_sanitizer_common to function correctly, one had to also use
options_parser.
This was because options_parser called __sanitizer::InitialiseCommonFlags. This
is a requirement for backtrace_sanitizer_common to work, as the sanitizer
unwinder uses the sanitizer_common flags and will SEGV on a null page if
they're not initialised correctly.
This patch removes this hidden dependency. You can now use
backtrace_sanitizer_common without the requirements of options_parser.
This patch also makes the GWP-ASan unit tests only have a soft dependency on
sanitizer-common. The unit tests previously explicitly used
__sanitizer::Printf, which is now provided under
tests/optional/printf_sanitizer_common. This allows Android to build the unit
tests using their own signal-safe printf().
Reviewers: eugenis
Reviewed By: eugenis
Subscribers: srhines, mgorny, #sanitizers, llvm-commits, vlad.tsyrklevich, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66684
llvm-svn: 369825
Summary:
Clang 4.* doesn't supply -fsanitize=fuzzer, and Clang 5.* doesn't supply
-fsanitize=fuzzer-no-link. Generally, in LLVM, fuzz targets are added through
the add_llvm_fuzzer build rule, which can't be used in compiler-rt (as it has
to be able to be standalone built).
Instead of adding tooling to add a dummy main (which kind of defeats the
purpose of these fuzz targets), we instead build the fuzz target only when the
Clang version is >= 6.*.
Reviewers: tejohnson
Subscribers: mgorny, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66682
llvm-svn: 369823
Remove c++ standard library dependency for now for @phosek. They have a
complicated build system that breaks with the fuzzer target here.
Also added a todo to remedy later.
Differential Revision: https://reviews.llvm.org/D66568
llvm-svn: 369606
Summary:
Note: Do not submit this documentation until Scudo support is reviewed and submitted (should be #[5]).
See D60593 for further information.
This patch introduces the public-facing documentation for GWP-ASan, as well as updating the definition of one of the options, which wasn't properly merged. The document describes the design and features of GWP-ASan, as well as how to use GWP-ASan from both a user's standpoint, and development documentation for supporting allocators.
Reviewers: jfb, morehouse, vlad.tsyrklevich
Reviewed By: morehouse, vlad.tsyrklevich
Subscribers: kcc, dexonsmith, kubamracek, cryptoad, jfb, #sanitizers, llvm-commits, vlad.tsyrklevich, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62875
llvm-svn: 369552
Summary:
Flips the switch to build stack_trace_compressor_fuzzer. This was recently
temporarily disabled in rL369079 as it was breaking the sanitizer buildbots.
My diagnosis of the problem is that on clang-only bootstrap builds, we build
gwp_asan before libfuzzer. This causes a discrepancy when the clang driver
attempts to link libclang_rt.fuzzer* as CMake doesn't see a dependency there.
I've (hopefully) fixed the issue by adding a direct dependency for the fuzz
target so CMake can resolve the build order properly. As part of this, the
libFuzzer 'fuzzer' target has to be discovered before the declaration of the
fuzz target.
pcc@ for mild review + notification as buildcop.
Reviewers: pcc
Reviewed By: pcc
Subscribers: mgorny, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66494
llvm-svn: 369551
Should hopefully fix the remainder of the buildbot issues. Just disabling this
for now with a comment that I'm working on it. Can actually fix the real problem
when I'm at a real computer.
llvm-svn: 369079
Used add_executable instead, as this allows a standalone compiler-rt to build,
as the add_llvm_executable build target isn't accessible in a standalone CRT
preparation.
llvm-svn: 369071
Summary:
This patch introduces stack frame compression to GWP-ASan. Each stack frame is
variable-length integer encoded as the difference between frame[i] and
frame[i - 1]. Furthermore, we use zig-zag encoding on the difference to ensure
that negative differences are also encoded into a relatively small number of
bytes.
Examples of what the compression looks like can be seen in
`gwp_asan/tests/compression.cpp`.
This compression can reduce the memory consumption cost of stack traces by
~50%.
Reviewers: vlad.tsyrklevich
Reviewed By: vlad.tsyrklevich
Subscribers: mgorny, #sanitizers, llvm-commits, eugenis, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66189
llvm-svn: 369048
Summary:
Updates the function signature and comments for backtracing (and printing
backtraces). This update brings GWP-ASan in line with future requirements for
stack frame compression, wherein the length of the trace is provided
explicitly, rather than relying on nullptr-termination.
Reviewers: vlad.tsyrklevich
Reviewed By: vlad.tsyrklevich
Subscribers: #sanitizers, llvm-commits, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D66099
llvm-svn: 368619
Summary:
Adds thread ID to PRNG seed for increased entropy. In particular, this allows
multiple runs in quick succession that will have different PRNG seeds, allowing
for better demos/testing.
Reviewers: kcc
Reviewed By: kcc
Subscribers: kubamracek, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D64453
llvm-svn: 366253
Summary:
Adds two flavours of generic unwinder and all the supporting cruft. If the
supporting allocator is okay with bringing in sanitizer_common, they can use
the fast frame-pointer based unwinder from sanitizer_common. Otherwise, we also
provide the backtrace() libc-based unwinder as well. Of course, the allocator
can always specify its own unwinder and unwinder-symbolizer.
The slightly changed output format is exemplified in the first comment on this
patch. It now better incorporates backtrace information, and displays
allocation details on the second line.
Reviewers: eugenis, vlad.tsyrklevich
Reviewed By: eugenis, vlad.tsyrklevich
Subscribers: srhines, kubamracek, mgorny, cryptoad, #sanitizers, llvm-commits, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D63841
llvm-svn: 364941
Summary:
Add a recursivity guard for GPA::allocate(). This means that any
recursive allocations will fall back to the supporting allocator. In future
patches, we will introduce stack trace collection support. The unwinder will be
provided by the supporting allocator, and we can't guarantee they don't call
malloc() (e.g. backtrace() on posix may call dlopen(), which may call malloc().
Furthermore, this patch packs the new TLS recursivity guard into a thread local
struct, so that TLS variables should be hopefully not fall across cache lines.
Reviewers: vlad.tsyrklevich, morehouse, eugenis
Reviewed By: eugenis
Subscribers: kubamracek, #sanitizers, llvm-commits, eugenis
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D63736
llvm-svn: 364356
to try and fix android buildbot. Also make sure that the empty dummy
test contains an output file name so the android_build.py wrapper script
doesn't check fail.
llvm-svn: 362758
Summary:
See D60593 for further information.
This patch introduces the core of GWP-ASan, being the guarded pool allocator. This class contains the logic for creating and maintaining allocations in the guarded pool. Its public interface is to be utilised by supporting allocators in order to provide sampled guarded allocation behaviour.
This patch also contains basic functionality tests of the allocator as unittests. The error-catching behaviour will be tested in upcoming patches that use Scudo as an implementing allocator.
Reviewers: vlad.tsyrklevich, eugenis, jfb
Reviewed By: vlad.tsyrklevich
Subscribers: dexonsmith, kubamracek, mgorny, cryptoad, jfb, #sanitizers, llvm-commits, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62872
llvm-svn: 362636
Summary:
See D60593 for further information.
This patch introduces the configuration options for GWP-ASan. In general, we expect the supporting allocator to populate the options struct, and give that to GWP-ASan during initialisation. For allocators that are okay with pulling in sanitizer_common, we also provide an optional parser that populates the gwp_asan::Options struct with values provided in the GWP_ASAN_OPTIONS environment variable.
This patch contains very little logic, and all of the testable components (i.e. the optional parser's internal logic) is tested as part of the sanitizer_common testbed.
Reviewers: vlad.tsyrklevich, morehouse, jfb
Reviewed By: morehouse
Subscribers: dexonsmith, kubamracek, mgorny, #sanitizers, llvm-commits, vitalybuka
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62698
llvm-svn: 362527
Looks like armv8 can't handle a thousand threads, which GWP-ASan
requests when running a synchronised mutex test. Limiting this to 100 to
attempt to fix the build issue.
llvm-svn: 362163
Summary:
See D60593 for further information.
This patch pulls out the mutex implementation and the required definitions file.
We implement our own mutex for GWP-ASan currently, because:
1. We must be compatible with the sum of the most restrictive elements of the supporting allocator's build system. Current targets for GWP-ASan include Scudo (on Linux and Fuchsia), and bionic (on Android).
2. Scudo specifies `-nostdlib++ -nonodefaultlibs`, meaning we can't use `std::mutex` or `mtx_t`.
3. We can't use `sanitizer_common`'s mutex, as the supporting allocators cannot afford the extra maintenance (Android, Fuchsia) and code size (Fuchsia) overheads that this would incur.
In future, we would like to implement a shared base mutex for GWP-ASan, Scudo and sanitizer_common. This will likely happen when both GWP-ASan and Scudo standalone are not in the development phase, at which point they will have stable requirements.
Reviewers: vlad.tsyrklevich, morehouse, jfb
Reviewed By: morehouse
Subscribers: dexonsmith, srhines, cfe-commits, kubamracek, mgorny, cryptoad, jfb, #sanitizers, llvm-commits, vitalybuka, eugenis
Tags: #sanitizers, #llvm, #clang
Differential Revision: https://reviews.llvm.org/D61923
llvm-svn: 362138
Mitch Phillips