Commit Graph

110 Commits

Author SHA1 Message Date
Kostya Kortchinsky e5c9e9f0bd [scudo] Quarantine optimization
Summary:
It turns out that the previous code construct was not optimizing the allocation
and deallocation of batches. The class id was read as a class member (even
though a precomputed one) and nothing else was optimized. By changing the
construct this way, the compiler actually optimizes most of the allocation and
deallocation away to only work with a single class id, which not only saves some
CPU but also some code footprint.

Reviewers: alekseyshl, dvyukov

Reviewed By: dvyukov

Subscribers: dvyukov, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D46961

llvm-svn: 332502
2018-05-16 18:12:31 +00:00
Kostya Kortchinsky d8803d3d92 [scudo] Adding an interface function to print allocator stats
Summary:
This adds `__scudo_print_stats` as an interface function to display the Primary
and Secondary allocator statistics for Scudo.

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D46016

llvm-svn: 330857
2018-04-25 18:52:29 +00:00
Kostya Kortchinsky 5a8bdc81d6 [scudo] Read ARM feature bits using Fuchsia APIs.
Summary:
    Fuchsia uses zx_system_get_features in lieu of getauxval.
    
    Use this call when checking for CRC32 support.

Reviewers: cryptoad

Reviewed By: cryptoad

Subscribers: delcypher, llvm-commits, #sanitizers, kristof.beyls, chrib

Differential Revision: https://reviews.llvm.org/D45896

llvm-svn: 330598
2018-04-23 14:53:13 +00:00
Kostya Kortchinsky 596b8b4a22 [sanitizer] Split Symbolizer/StackTraces from core RTSanitizerCommon
Summary:
Host symbolizer & stacktraces related code in their own RT:
`RTSanitizerCommonSymbolizer`, which is "libcdep" by nature. Symbolizer &
stacktraces specific code that used to live in common files is moved to a new
file `sanitizer_symbolizer_report.cc` as is.

The purpose of this is the enforce a separation between code that relies on
symbolization and code that doesn't. This saves the inclusion of spurious code
due to the interface functions with default visibility, and the extra data
associated.

The following sanitizers makefiles were modified & tested locally:
- dfsan: doesn't require the new symbolizer RT
- esan: requires it
- hwasan: requires it
- lsan: requires it
- msan: requires it
- safestack: doesn't require it
- xray: doesn't require it
- tsan: requires it
- ubsan: requires it
- ubsan_minimal: doesn't require it
- scudo: requires it (but not for Fuchsia that has a minimal runtime)

This was tested locally on Linux, Android, Fuchsia.

Reviewers: alekseyshl, eugenis, dberris, kubamracek, vitalybuka, dvyukov, mcgrathr

Reviewed By: alekseyshl, vitalybuka

Subscribers: srhines, kubamracek, mgorny, krytarowski, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D45457

llvm-svn: 330131
2018-04-16 16:32:19 +00:00
Kostya Kortchinsky 4563b78b99 [sanitizer] Allow for the allocator "names" to be set by the tools
Summary:
In the same spirit of SanitizerToolName, allow the Primary & Secondary
allocators to have names that can be set by the tools via PrimaryAllocatorName
and SecondaryAllocatorName.

Additionally, set a non-default name for Scudo.

Reviewers: alekseyshl, vitalybuka

Reviewed By: alekseyshl, vitalybuka

Subscribers: kubamracek, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D45600

llvm-svn: 330055
2018-04-13 19:21:27 +00:00
Kostya Kortchinsky bafba57252 [scudo] Remove duplicate cmake flags
Summary:
Now that common options are propagated again for runtimes build with D45507,
the -f{data,function}-sections flags are now duplicates, remove them.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: mgorny, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D45575

llvm-svn: 329925
2018-04-12 16:41:57 +00:00
Kostya Kortchinsky eeee252d50 [scudo] Fuchsia minimal shared runtime
Summary:
Fuchsia requires its Scudo shared runtime to not be C++ dependant. Since they
don't use UBSan in conjunction with Scudo, we can just remove the runtime,
and add the extra `nostdinc++` and `nostdlib++` flags. No need for Coverage
either. This allows to keep things going while working on additional splits
of sanitizer_commong and a more minimal runtime.

Reviewers: phosek, flowerhack, alekseyshl

Reviewed By: phosek, alekseyshl

Subscribers: mgorny, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D44791

llvm-svn: 328625
2018-03-27 14:40:39 +00:00
Kostya Kortchinsky 988fab3f66 [sanitizer] Split coverage into separate RT in sanitizer_common
Summary:
`sanitizer_common`'s coverage support is fairly well separated, and libcdep by
default. Several sanitizers don't make use of coverage, and as far as I can
tell do no benefit from the extra dependencies pulled in by the coverage public
interface functions.

The following sanitizers call `InitializeCoverage` explicitely: MSan, ASan,
LSan, HWAsan, UBSan. On top of this, any sanitizer bundling RTUBSan should
add the coverage RT as well: ASan, Scudo, UBSan, CFI (diag), TSan, MSan, HWAsan.

So in the end the following have no need: DFSan, ESan, CFI, SafeStack (nolibc
anyway), XRay, and the upcoming Scudo minimal runtime.

I tested this with all the sanitizers check-* with gcc & clang, and in
standalone on Linux & Android, and there was no issue. I couldn't test this on
Mac, Fuchsia, BSDs, & Windows for lack of an environment, so adding a bunch of
people for additional scrunity. I couldn't test HWAsan either.

Reviewers: eugenis, vitalybuka, alekseyshl, flowerhack, kubamracek, dberris, rnk, krytarowski

Reviewed By: vitalybuka, alekseyshl, flowerhack, dberris

Subscribers: mgorny, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D44701

llvm-svn: 328204
2018-03-22 15:04:31 +00:00
Kostya Kortchinsky a51139046e [scudo] Add Chunk::getSize, rework Chunk::getUsableSize
Summary:
Using `getActuallyAllocatedSize` from the Combined resulting in mediocre
compiled code, as the `ClassId != 0` predicament was not propagated there,
resulting in additional branches and dead code. Move the logic in the frontend,
which results in better compiled code. Also I think it makes it slightly easier
to distinguish between the size the user requested, and the size that was
actually allocated by the allocator.

`const` a couple of things as well.

This has no functional impact.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D44444

llvm-svn: 327525
2018-03-14 15:50:32 +00:00
Kostya Kortchinsky e95ef87663 [scudo] Secondary allocator overhaul to support Windows
Summary:
The need for this change stems from the fact that Windows doesn't support
partial unmapping (`MEM_RELEASE` implies the entire allocated region). So we
now have to keep track of the reserved region and the committed region, so that
we can function without the trimming we did when dealing with larger alignments.

Instead of just having a `ReservedAddressRange` per chunk, we introduce a
`LargeChunkHeader` (and `LargeChunk` namespace) that additionally holds the
committed size and the usable size. The former is needed for stats purposes,
the latter is used by the frontend. Requiring both is debatable, we could only
work with the usable size but then be off by up to a page per chunk when
dealing with stats.

Additionally, we introduce more stats since they turned out to be useful for
experiments, and a `PrintStats` function that will be used by the combined
allocator in later patch.

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D43949

llvm-svn: 327321
2018-03-12 19:29:38 +00:00
Kostya Kortchinsky e245ec0cf0 [scudo] Make logging more consistent
Summary:
A few changes related to logging:
- prepend `Scudo` to the error messages so that users can identify that we
  reported an error;
- replace a couple of `Report` calls in the RSS check code with
  `dieWithMessage`/`Print`, mark a condition as `UNLIKELY` in the process;
- change some messages so that they all look more or less the same. This
  includes the `CHECK` message;
- adapt a couple of tests with the new strings.

A couple of side notes: this results in a few 1-line-blocks, for which I left
brackets. There doesn't seem to be any style guide for that, I can remove them
if need be. I didn't use `SanitizerToolName` in the strings, but directly
`Scudo` because we are the only users, I could change that too.

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: mgorny, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D44171

llvm-svn: 326901
2018-03-07 16:22:16 +00:00
Kostya Kortchinsky 7dc5137581 [scudo] Use gc-sections by default
Summary:
If not using `-Wl,--gc-sections`, a whole lot of unused `sanitizer_common` code
and related static variables are pulled into the shared library.
Keep the binary size smaller, and its memory footprint smaller as well, by
using the compiler flags `-ffunction-section` & `-fdata-sections` by default,
as well as the linker flags `-Wl,--gc-sections`.

Current experiments show a large discrepency between binary sizes generated
by gcc (big) and clang (small). I am not sure yet how I can make a test that
would encompass both, so it's an outstanding work item.

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: mgorny, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D44121

llvm-svn: 326833
2018-03-06 20:13:37 +00:00
Kostya Kortchinsky beeea6227b [scudo] Introduce Chunk::getHeaderSize
Summary:
Instead of using `AlignedChunkHeaderSize`, introduce a `constexpr` function
`getHeaderSize` in the `Chunk` namespace. Switch `RoundUpTo` to a `constexpr`
as well (so we can use it in `constexpr` declarations). Mark a few variables
in the areas touched as `const`.

Overall this has no functional change, and is mostly to make things a bit more
consistent.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D43772

llvm-svn: 326206
2018-02-27 16:14:49 +00:00
Kostya Kortchinsky 2833383cd4 [scudo] Allow options to be defined at compile time
Summary:
Allow for options to be defined at compile time, like is already the case for
other sanitizers, via `SCUDO_DEFAULT_OPTIONS`.

Reviewers: alekseyshl, dberris

Reviewed By: alekseyshl, dberris

Subscribers: kubamracek, delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D42980

llvm-svn: 324620
2018-02-08 16:29:48 +00:00
Kostya Kortchinsky 8c4ca0bbea [scudo] Minor Secondary changes
Summary:
Few changes to the secondary:
- mark `const` variables as such;
- change some `CHECK` to `DCHECK`: I don't feel we need to be as conservative as
  we were with out checks, as they are the results of our own computation.
- mark a condition as `UNLIKELY`.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42696

llvm-svn: 323997
2018-02-01 20:00:42 +00:00
Kostya Kortchinsky 4223af42b8 [scudo] Add default implementations for weak functions
Summary:
This is in preparation for platforms where `SANITIZER_SUPPORTS_WEAK_HOOKS` is 0.
They require a default implementation.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: delcypher, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D42557

llvm-svn: 323795
2018-01-30 17:59:49 +00:00
Kostya Kortchinsky 4b4db0057f [scudo] Overhaul malloc related interceptors
Summary:
This is a follow-up to D42506.

There are a few of things that bothered me about `scudo_interceptors.cpp`:
- the filename is a misnomer: it intercepts some functions, but the rest (C++)
  is actually in `scudo_new_delete.cpp`. I feel like `scudo_malloc.cpp` is more
  appropriate (ASan uses the same naming scheme);
- we do not need "full" interceptors, since we are never accessing the
  unsanitized version of the functions, we just need the
  `extern "C" INTERCEPTOR_ATTRIBUTE` part of it to just call our functions;
- a couple of functions where duplicated while they could just be `ALIAS`'d;
- use the `SANITIZER_INTERCEPT_*` defines to hide the unneeded interceptors;
- use `SIZE_T` instead of `uptr`: while it's the same behind the curtain,
  the former is meant for this use case.

In the end there is no functional change on the currently supported platforms
(Linux, Android).

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: mgorny, hintonda, delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42546

llvm-svn: 323464
2018-01-25 20:42:44 +00:00
Kostya Kortchinsky fc45e4a3f1 [scudo] Remove SANITIZER_LINUX requirement for the malloc interceptors
Summary:
Currently all platforms are using the `scudo_interceptors.cpp` interceptors.

We might to come up with platform specific interceptors when/if we get Apple &
Windows, but as of now, that allows for Fuchsia to use them.

`scudo_new_delete.cpp` didn't have the `#if SANITIZER_LINUX` so it's good to go.

Reviewers: alekseyshl, flowerhack

Reviewed By: flowerhack

Subscribers: delcypher, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42506

llvm-svn: 323386
2018-01-24 22:46:34 +00:00
Kostya Kortchinsky 1ebebde8b7 [scudo] Allow for weak hooks, gated by a define
Summary:
Hooks in the allocation & deallocation paths can be a security risk (see for an
example https://scarybeastsecurity.blogspot.com/2016/11/0day-exploit-advancing-exploitation.html
which used the glibc's __free_hook to complete exploitation).

But some users have expressed a need for them, even if only for tests and
memory benchmarks. So allow for `__sanitizer_malloc_hook` &
`__sanitizer_free_hook` to be called if defined, and gate them behind a global
define `SCUDO_CAN_USE_HOOKS` defaulting to 0.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42430

llvm-svn: 323278
2018-01-23 23:07:42 +00:00
Kostya Kortchinsky 5435b68a11 [scudo] Pass SANITIZER_COMMON_LINK_FLAGS to the shared library LINK_FLAGS
Summary:
We somehow never did it, and it raised no issue until now, when trying to
enable Fuchsia as a supported Scudo platform in the cmake config.

So propagate SANITIZER_COMMON_LINK_FLAGS for now.

Reviewers: alekseyshl, flowerhack

Reviewed By: flowerhack

Subscribers: mgorny, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42314

llvm-svn: 322999
2018-01-19 22:17:39 +00:00
Kostya Kortchinsky 33802be579 [scudo] Fix for the Scudo interface function scope
Summary:
A forgotten include in `scudo_allocator.cpp` made the symbol only local :/

Before:
```
nm ./lib/clang/7.0.0/lib/linux/libclang_rt.scudo-i686-android.so | grep rss
00024730 t __scudo_set_rss_limit
```
After:
```
nm ./lib/clang/7.0.0/lib/linux/libclang_rt.scudo-i686-android.so | grep rs
00024760 T __scudo_set_rss_limit
```
And we want `T`!

This include also means that we can get rid of the `extern "C"` in the C++
file, the compiler does fine without it (note that this was already the case
for all the `__sanitizer_*` interface functions.

Reviewers: alekseyshl, eugenis

Reviewed By: eugenis

Subscribers: #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42199

llvm-svn: 322782
2018-01-17 23:10:02 +00:00
Kostya Kortchinsky 255913b3a0 [scudo] Limit by default the TSD pool to 2 on Android
Summary:
jemalloc on Android currently uses 2 arenas
(https://android.googlesource.com/platform/external/jemalloc/+/master/Android.bp#64).
Since the Android toolchain absorbs compiler-rt and compiles it as is, we have
to enforce the same limit to somehow stay competitive in terms of memory usage.

The changes could either go in:
- `scudo_platform.h` with a default for Android of 2 (this is the solution
  implemented here);
- in `CMakeLists.txt` adding -DSCUDO_SHARED_TSD_POOL_SIZE=2 for Android.
- something else?

I don't have a strong opinion on how to do it, but it has to be done upstream
anyway.

Reviewers: alekseyshl, eugenis

Reviewed By: alekseyshl, eugenis

Subscribers: srhines, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D42194

llvm-svn: 322764
2018-01-17 21:54:48 +00:00
Kostya Kortchinsky 0bf9c5eee5 [scudo] Add SANITIZER_CXX_ABI_LIBRARY to SCUDO_DYNAMIC_LIBS
Summary:
This is needed for the shared runtime since we are pulling RTUbsan in.

Otherwise some builds might fail with errors such as:
`error: undefined reference to '__dynamic_cast'`

Reviewers: alekseyshl, srhines

Reviewed By: srhines

Subscribers: kongyi, pirama, chh, mgorny, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D41995

llvm-svn: 322389
2018-01-12 18:45:30 +00:00
Kostya Kortchinsky 541c5a0797 [scudo] s/unsigned long/size_t/ for __scudo_set_rss_limit
Summary:
`__scudo_set_rss_limit`'s `LimitMb` should really be a `size_t`. Update
accordingly the prototype. To avoid the `NOLINT` and conform with the other
Sanitizers, use the sanitizers types for the internal definition. This should
have no functional change.

Additionally, capitalize a variable name to follow the LLVM coding standards.

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D41704

llvm-svn: 321803
2018-01-04 17:05:04 +00:00
Kostya Kortchinsky efe3d3436a [scudo] Refactor ScudoChunk
Summary:
The initial implementation used an ASan like Chunk class that was deriving from
a Header class. Due to potential races, we ended up working with local copies
of the Header and never using the parent class fields. ScudoChunk was never
constructed but cast, and we were using `this` as the pointer needed for our
computations. This was meh.

So we refactored ScudoChunk to be now a series of static functions within the
namespace `__scudo::Chunk` that take a "user" pointer as first parameter (former
`this`). A compiled binary doesn't really change, but the code is more sensible.

Clang tends to inline all those small function (in -O2), but GCC left a few not
inlined, so we add the `INLINE` keyword to all.

Since we don't have `ScudoChunk` pointers anymore, a few variables were renamed
here and there to introduce a clearer distinction between a user pointer
(usually `Ptr`) and a backend pointer (`BackendPtr`).

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D41200

llvm-svn: 320745
2017-12-14 21:32:57 +00:00
Kostya Kortchinsky f22f5fe910 [scudo] Adding a public Scudo interface
Summary:
The first and only function to start with allows to set the soft or hard RSS
limit at runtime. Add associated tests.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: mgorny, #sanitizers, llvm-commits

Differential Revision: https://reviews.llvm.org/D41128

llvm-svn: 320611
2017-12-13 20:41:35 +00:00
Kostya Kortchinsky f50246da65 [sanitizer] Introduce a vDSO aware timing function
Summary:
See D40657 & D40679 for previous versions of this patch & description.

A couple of things were fixed here to have it not break some bots.
Weak symbols can't be used with `SANITIZER_GO` so the previous version was
breakin TsanGo. I set up some additional local tests and those pass now.

I changed the workaround for the glibc vDSO issue: `__progname` is initialized
after the vDSO and is actually public and of known type, unlike
`__vdso_clock_gettime`. This works better, and with all compilers.

The rest is the same.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, kubamracek, krytarowski, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D41121

llvm-svn: 320594
2017-12-13 16:23:54 +00:00
Kostya Kortchinsky 4ac0b1e6e9 [scudo] Inline getScudoChunk function.
Summary:
getScudoChunk function is implicitly inlined for optimized builds on
clang, but not on gcc. It's a small enough function that it seems
sensible enough to just inline it by default.

Reviewers: cryptoad, alekseyshl

Reviewed By: cryptoad

Differential Revision: https://reviews.llvm.org/D41138

llvm-svn: 320592
2017-12-13 16:10:39 +00:00
Kostya Kortchinsky ab5f6aaa75 [sanitizer] Revert rL320409
Summary: D40679 broke a couple of builds, reverting while investigating.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, kubamracek, krytarowski, llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D41088

llvm-svn: 320417
2017-12-11 21:03:12 +00:00
Kostya Kortchinsky d276d72441 [sanitizer] Introduce a vDSO aware time function, and use it in the allocator [redo]
Summary:
Redo of D40657, which had the initial discussion. The initial code had to move
into a libcdep file, and things had to be shuffled accordingly.

`NanoTime` is a time sink when checking whether or not to release memory to
the OS. While reducing the amount of calls to said function is in the works,
another solution that was found to be beneficial was to use a timing function
that can leverage the vDSO.

We hit a couple of snags along the way, like the fact that the glibc crashes
when clock_gettime is called from a preinit_array, or the fact that
`__vdso_clock_gettime` is mangled (for security purposes) and can't be used
directly, and also that clock_gettime can be intercepted.

The proposed solution takes care of all this as far as I can tell, and
significantly improve performances and some Scudo load tests with memory
reclaiming enabled.

@mcgrathr: please feel free to follow up on
https://reviews.llvm.org/D40657#940857 here. I posted a reply at
https://reviews.llvm.org/D40657#940974.

Reviewers: alekseyshl, krytarowski, flowerhack, mcgrathr, kubamracek

Reviewed By: alekseyshl, krytarowski

Subscribers: #sanitizers, mcgrathr, srhines, llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D40679

llvm-svn: 320409
2017-12-11 19:23:12 +00:00
Kostya Kortchinsky 9fcb91b3eb [scudo] Minor code generation improvement
Summary:
It looks like clang was generating somewhat weird assembly with the current
code. `FromPrimary`, even though `const`,  was replaced every time with the code
generated for `size <= SizeClassMap::kMaxSize` instead of using a variable or
register, and `FromPrimary` didn't induce `ClassId != 0` for the compiler, so a
dead branch was generated for `getActuallyAllocatedSize(Ptr, ClassId)` since
it's never called for `ClassId = 0` (Secondary backed allocations) [this one
was more wishful thinking on my side than anything else].

I rearranged the code bit so that the generated assembly is less clunky.

Also changed 2 whitespace inconsistencies that were bothering me.

Reviewers: alekseyshl, flowerhack

Reviewed By: flowerhack

Subscribers: llvm-commits, #sanitizers

Differential Revision: https://reviews.llvm.org/D40976

llvm-svn: 320160
2017-12-08 16:36:37 +00:00
Kostya Kortchinsky ddf4ef3959 [scudo] Correct performance regression in Secondary
Summary:
This wasn't noticed: `RoundUpTo` doesn't produce a constant expression, so the
sizes were not constant either. Enforce them to be static const, replace
`RoundUpTo` by its expression. The compiler can now optimize the associated
computations accordingly.

Also looking at the produced assembly, `PageSize` was fetched multiple times
during `Allocate`, so keep a local value of it. As a result it's fetched once
and kept in a register.

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D40862

llvm-svn: 319903
2017-12-06 16:53:24 +00:00
Kostya Kortchinsky df6ba242bf [scudo] Get rid of the thread local PRNG & header salt
Summary:
It was deemed that the salt in the chunk header didn't improve security
significantly (and could actually decrease it). The initial idea was that the
same chunk would different headers on different allocations, allowing for less
predictability. The issue is that gathering the same chunk header with different
salts can give information about the other "secrets" (cookie, pointer), and that
if an attacker leaks a header, they can reuse it anyway for that same chunk
anyway since we don't enforce the salt value.

So we get rid of the salt in the header. This means we also get rid of the
thread local Prng, and that we don't need a global Prng anymore as well. This
makes everything faster.

We reuse those 8 bits to store the `ClassId` of a chunk now (0 for a secondary
based allocation). This way, we get some additional speed gains:
- `ClassId` is computed outside of the locked block;
- `getActuallyAllocatedSize` doesn't need the `GetSizeClass` call;
- same for `deallocatePrimary`;
We add a sanity check at init for this new field (all sanity checks are moved
in their own function, `init` was getting crowded).

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D40796

llvm-svn: 319791
2017-12-05 17:08:29 +00:00
Kostya Kortchinsky cf5b4af820 [scudo] Allow for compile-time choice of the SizeClassMap
Summary:
With this change, we allow someone to chose the `SizeClassMap` they want to use
at compile time via a define.

I feel somewhat unimaginative with the name of the defines, so if someone has a
better idea, let me know. I have been alternating between those and
`SCUDO_USE_xxx_SIZECLASSMAP` which is clearer but also longer. The issue with
those is that it wouldn't be consistent with `SCUDO_TSD_EXCLUSIVE` that should
probably become `SCUDO_USE_EXCLUSIVE_TSD` maybe?

Anyway, naming is hard, and I am not sure what makes more sense!

Reviewers: alekseyshl, flowerhack

Reviewed By: alekseyshl

Subscribers: llvm-commits, srhines

Differential Revision: https://reviews.llvm.org/D40521

llvm-svn: 319350
2017-11-29 19:52:09 +00:00
Kostya Kortchinsky 06b891f693 [scudo] Workaround for uninitialized Bionic globals
Summary:
Bionic doesn't initialize its globals early enough. This causes issues when
trying to access them from a preinit_array (b/25751302) or from another
constructor called before the libc one (b/68046352). __progname is initialized
after the other globals, so we can check its value to know if calling
`getauxval` is safe.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, llvm-commits

Differential Revision: https://reviews.llvm.org/D40504

llvm-svn: 319099
2017-11-27 21:34:43 +00:00
Kostya Kortchinsky 0207b6fbbf [scudo] Overhaul hardware CRC32 feature detection
Summary:
This patch aims at condensing the hardware CRC32 feature detection and making
it slightly more effective on Android.

The following changes are included:
- remove the `CPUFeature` enum, and get rid of one level of nesting of
  functions: we only used CRC32, so we just implement and use
  `hasHardwareCRC32`;
- allow for a weak `getauxval`: the Android toolchain is compiled at API level
  14 for Android ARM, meaning no `getauxval` at compile time, yet we will run
  on API level 27+ devices. The `/proc/self/auxv` fallback can work but is
  worthless for a process like `init` where the proc filesystem doesn't exist
  yet. If a weak `getauxval` doesn't exist, then fallback.
- couple of extra corrections.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: kubamracek, aemerson, srhines, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D40322

llvm-svn: 318859
2017-11-22 18:30:44 +00:00
Kostya Kortchinsky 5a3fdbd829 [scudo] Make getNumberOfCPUs Fuchsia compliant v2
Summary:
This change allows Fuchsia to boot properly using the Scudo allocator.

A first version of this commit was reverted by rL317834 because it broke Android
builds for toolchains generated with older NDKs. This commit introduces a
fall back to solve that issue.

Reviewers: cryptoad, krytarowski, rnk, alekseyshl

Reviewed By: cryptoad, krytarowski, alekseyshl

Subscribers: llvm-commits, srhines, kubamracek, krytarowski

Differential Revision: https://reviews.llvm.org/D40121

llvm-svn: 318802
2017-11-21 21:14:00 +00:00
Kostya Kortchinsky 58f2656d7e [scudo] Soft and hard RSS limit checks
Summary:
This implements an opportunistic check for the RSS limit.

For ASan, this was implemented thanks to a background thread checking the
current RSS vs the set limit every 100ms. This was deemed problematic for Scudo
due to potential Android concerns (Zygote as pointed out by Aleksey) as well as
the general inconvenience of having a permanent background thread.

If a limit (soft or hard) is specified, we will attempt to update the RSS limit
status (exceeded or not) every 100ms. This is done in an opportunistic way: if
we can update it, we do it, if not we return the current status, mostly because
we don't need it to be fully consistent (it's done every 100ms anyway). If the
limit is exceeded `allocate` will act as if OOM for a soft limit, or just die
for a hard limit.

We use the `common_flags()`'s `hard_rss_limit_mb` & `soft_rss_limit_mb` for
configuration of the limits.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D40038

llvm-svn: 318301
2017-11-15 16:40:27 +00:00
Kostya Kortchinsky a2b715f883 [scudo] Simplify initialization and flags
Summary:
This is mostly some cleanup and shouldn't affect functionalities.

Reviewing some code for a future addition, I realized that the complexity of
the initialization path was unnecessary, and so was maintaining a structure
for the allocator options throughout the initialization.

So we get rid of that structure, of an extraneous level of nesting for the
`init` function, and correct a couple of related code inaccuracies in the
flags cpp.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39974

llvm-svn: 318157
2017-11-14 16:14:53 +00:00
Kostya Kortchinsky 2ba105a7da [sanitizer] Update scudo to use new API
Summary:
The ScudoAllocator uses a SecondaryHeader to keep track of the size and base address of each mmap'd chunk.

This aligns well with what the ReservedAddressRange is trying to do.  This changeset converts the scudo allocator from using the MmapNoAccess/MmapFixed APIs to the ReservedAddressRange::Init and ::Map APIs.  In doing so, it replaces the SecondayHeader struct with the ReservedAddressRange object.

This is part 3 of a 4 part changeset; part 1 https://reviews.llvm.org/D39072 and part 2 https://reviews.llvm.org/D38592

Reviewers: alekseyshl, mcgrathr, cryptoad, phosek

Reviewed By: cryptoad

Subscribers: llvm-commits, cryptoad, kubamracek

Differential Revision: https://reviews.llvm.org/D38593

llvm-svn: 318080
2017-11-13 20:38:22 +00:00
Kostya Kortchinsky 36e56785b4 [scudo] Bump the Android API level requirement to 21 for getauxval
Summary:
`getauxval` was introduced in 18 & 21 depending on the architecture. Bump the
requirement to 21.

It also turns out that the NDK is finicky: NDK r13b doesn't include sys/auxv.h
when creating a standalone toolchain at API level 19 for ARM. So 18 didn't work
well with older NDKs.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: aemerson, srhines, llvm-commits, kristof.beyls

Differential Revision: https://reviews.llvm.org/D39905

llvm-svn: 317907
2017-11-10 19:01:17 +00:00
Kostya Kortchinsky 5604ad1c9b [sanitizer] Revert rL317822
Summary:
This reverts D39490.

For toolchains generated with older NDKs (<=r13b as far as we tested),
`cpu_set_t` doesn't exist in `sched.h`.
We have to figure out another way to get the number of CPUs without this.

Reviewers: rnk

Reviewed By: rnk

Subscribers: kubamracek, llvm-commits, krytarowski

Differential Revision: https://reviews.llvm.org/D39867

llvm-svn: 317834
2017-11-09 21:26:07 +00:00
Kostya Kortchinsky 6458216b28 [scudo] Make getNumberOfCPUs Fuchsia compliant
Summary: This change allows Fuchsia to boot properly using the Scudo allocator.

Reviewers: cryptoad, alekseyshl, krytarowski

Reviewed By: cryptoad, krytarowski

Subscribers: rnk, krytarowski, kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D39490

llvm-svn: 317822
2017-11-09 19:18:55 +00:00
Kostya Kortchinsky 6edadae34a [sanitizer] Add Scudo to the sanitizer lint checks.
Summary:
Scudo abides by the coding style enforced by the sanitizer_common
linter, but as of right now, it's not linter-enforced.

Add Scudo to the list of directories checked by check_lint.sh.

Also: fixes some linter errors found after getting this running.

Reviewers: cryptoad

Reviewed By: cryptoad

Subscribers: llvm-commits, kubamracek

Differential Revision: https://reviews.llvm.org/D39757

llvm-svn: 317699
2017-11-08 16:42:29 +00:00
Reid Kleckner f7fdac4508 Revert "[scudo] Make getNumberOfCPUs Fuchsia compliant"
This reverts commit r317604.

Android doesn't have cpu_set_t.

llvm-svn: 317655
2017-11-08 01:33:15 +00:00
Kostya Kortchinsky 4e8ce0225f [scudo] Make getNumberOfCPUs Fuchsia compliant
Summary: This change allows Fuchsia to boot properly using the Scudo allocator.

Reviewers: cryptoad, alekseyshl, krytarowski

Reviewed By: cryptoad, krytarowski

Subscribers: krytarowski, kubamracek, llvm-commits

Differential Revision: https://reviews.llvm.org/D39490

llvm-svn: 317604
2017-11-07 19:30:08 +00:00
Kostya Kortchinsky 4a0ebbfe97 [scudo] Rearrange #include order
Summary:
To be compliant with https://llvm.org/docs/CodingStandards.html#include-style,
system headers have to come after local headers.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39623

llvm-svn: 317390
2017-11-03 23:48:25 +00:00
Kostya Kortchinsky d937b0a10c [scudo] Implement stricter separation of C vs C++
Summary:
Initially, Scudo had a monolithic design where both C and C++ functions were
living in the same library. This was not necessarily ideal, and with the work
on -fsanitize=scudo, it became more apparent that this needed to change.

We are splitting the new/delete interceptor in their own C++ library. This
allows more flexibility, notably with regard to std::bad_alloc when the work is
done. This also allows us to not link new & delete when using pure C.

Additionally, we add the UBSan runtimes with Scudo, in order to be able to have
a -fsanitize=scudo,undefined in Clang (see work in D39334).

The changes in this patch:
- split the cxx specific code in the scudo cmake file into a new library;
  (remove the spurious foreach loop, that was not necessary)
- add the UBSan runtimes (both C and C++);
- change the test cmake file to allow for specific C & C++ tests;
- make C tests pure C, rename their extension accordingly.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: srhines, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D39461

llvm-svn: 317097
2017-11-01 15:28:20 +00:00
Kostya Kortchinsky 91b7558ca8 [scudo] Allow to specify the maximum number of TSDs at compile time
Summary:
This introduces `SCUDO_MAX_CACHES` allowing to define an upper bound to the
number of `ScudoTSD` created in the Shared TSD model (by default 32U).
This name felt clearer than `SCUDO_MAX_TSDS` which is technically what it really
is. I am opened to suggestions if that doesn't feel right.

Additionally change `getNumberOfCPUs` to return a `u32` to be more consistent.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39338

llvm-svn: 316788
2017-10-27 20:10:14 +00:00
Kostya Kortchinsky f9008a3a06 [scudo] Remove comment about security of the 32-bit allocator
Summary:
The 32-bit allocator is now on par with the 64-bit in terms of security (chunks
randomization is done, batches separation is done).

Unless objection, the comment can go away.

Reviewers: alekseyshl

Reviewed By: alekseyshl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D39303

llvm-svn: 316620
2017-10-25 22:00:26 +00:00