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
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:
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:
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:
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:
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
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
Summary:
Removed dependency on c++ standard library. Some supporting allocators (namely Scudo on Fuchsia, and shortly, scudo standalone) has a hard requirement of no c++stdlib.
This patch updates the build system so that we don't have any c++ stdlib dependencies. It also will conveniently fix a racy build-order bug discrepency between GWP-ASan and libc++.
Reviewers: phosek, morehouse
Reviewed By: phosek, morehouse
Subscribers: kubamracek, mgorny, cryptoad, #sanitizers, llvm-commits, beanz, smeenai, vitalybuka
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62048
llvm-svn: 360982
Summary:
See D60593 for further information.
This patch slices off the PRNG implementation and the initial build files for GWP-ASan.
Reviewers: vlad.tsyrklevich, morehouse, vitalybuka
Reviewed By: morehouse
Subscribers: srhines, kubamracek, mgorny, #sanitizers, llvm-commits, cryptoad, eugenis
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D61867
llvm-svn: 360710
Mitch Phillips