Introduce a function __scudo_get_error_info() that may be called to interpret
a crash resulting from a memory error, potentially in another process,
given information extracted from the crashing process. The crash may be
interpreted as a use-after-free, buffer overflow or buffer underflow.
Also introduce a feature to optionally record a stack trace for each
allocation and deallocation. If this feature is enabled, a stack trace for
the allocation and (if applicable) the deallocation will also be available
via __scudo_get_error_info().
Differential Revision: https://reviews.llvm.org/D77283
Summary:
Most of our larger data is dynamically allocated (via `map`) but it
became an hindrance with regard to init time, for a cost to benefit
ratio that is not great. So change the `TSD`s, `RegionInfo`, `ByteMap`
to be static.
Additionally, for reclaiming, we used mapped & unmapped a buffer each
time, which is costly. It turns out that we can have a static buffer,
and that there isn't much contention on it.
One of the other things changed here, is that we hard set the number
of TSDs on Android to the maximum number, as there could be a
situation where cores are put to sleep and we could miss some.
Subscribers: mgorny, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D74696
Summary:
Add a method to set the release to OS value as the system runs,
and allow this to be set differently in the primary and the secondary.
Also, add a default value to use for primary and secondary. This
allows Android to have a default that is different for
primary/secondary.
Update mallopt to support setting the release to OS value.
Reviewers: pcc, cryptoad
Reviewed By: cryptoad
Subscribers: cryptoad, jfb, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D74448
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
When the hardware and operating system support the ARM Memory Tagging
Extension, tag primary allocation granules with a random tag. The granules
either side of the allocation are tagged with tag 0, which is normally
excluded from the set of tags that may be selected randomly. Memory is
also retagged with a random tag when it is freed, and we opportunistically
reuse the new tag when the block is reused to reduce overhead. This causes
linear buffer overflows to be caught deterministically and non-linear buffer
overflows and use-after-free to be caught probabilistically.
This feature is currently only enabled for the Android allocator
and depends on an experimental Linux kernel branch available here:
https://github.com/pcc/linux/tree/android-experimental-mte
All code that depends on the kernel branch is hidden behind a macro,
ANDROID_EXPERIMENTAL_MTE. This is the same macro that is used by the Android
platform and may only be defined in non-production configurations. When the
userspace interface is finalized the code will be updated to use the stable
interface and all #ifdef ANDROID_EXPERIMENTAL_MTE will be removed.
Differential Revision: https://reviews.llvm.org/D70762
Summary:
fork() wasn't well (or at all) supported in Scudo. This materialized
in deadlocks in children.
In order to properly support fork, we will lock the allocator pre-fork
and unlock it post-fork in parent and child. This is done via a
`pthread_atfork` call installing the necessary handlers.
A couple of things suck here: this function allocates - so this has to
be done post initialization as our init path is not reentrance, and it
doesn't allow for an extra pointer - so we can't pass the allocator we
are currently working with.
In order to work around this, I added a post-init template parameter
that gets executed once the allocator is initialized for the current
thread. Its job for the C wrappers is to install the atfork handlers.
I reorganized a bit the impacted area and added some tests, courtesy
of cferris@ that were deadlocking prior to this fix.
Subscribers: jfb, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D72470
Summary: Bionic was modified to have all function names consistent. Modify the code and get rid of the special case for bionic since it's no longer needed.
Reviewers: cryptoad
Reviewed By: cryptoad
Subscribers: srhines, llvm-commits, #sanitizers
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D70031
Summary:
Initially, our malloc_info was returning ENOTSUP, but Android would
rather have it return successfully and write a barebone XML to the
stream, so we will oblige.
Add an associated test.
Reviewers: cferris, morehouse, hctim, eugenis, vitalybuka
Reviewed By: morehouse
Subscribers: delcypher, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D68427
llvm-svn: 373754
Summary:
Android requires additional stats in mallinfo. While we can provide
right away the number of bytes mapped (Primary+Secondary), there was
no way to get the number of free bytes (only makes sense for the
Primary since the Secondary unmaps everything on deallocation).
An approximation could be `StatMapped - StatAllocated`, but since we
are mapping in `1<<17` increments for the 64-bit Primary, it's fairly
inaccurate.
So we introduce `StatFree` (note it's `Free`, not `Freed`!), which
keeps track of the amount of Primary blocks currently unallocated.
Reviewers: cferris, eugenis, vitalybuka, hctim, morehouse
Reviewed By: morehouse
Subscribers: delcypher, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D66112
llvm-svn: 368866
Summary:
This is a redo of D63612.
Two problems came up on some bots:
- `__builtin_umull_overflow` was not declared. This is likely due to an
older clang or gcc, so add a guard with `__has_builtin` and fallback
to a division in the event the builtin doesn't exist;
- contradicting definition for `malloc`, etc. This is AFAIU due to the
fact that we ended up transitively including `stdlib.h` in the `.inc`
due to it being the flags parser header: so move the include to the
cc instead.
This should fix the issues, but since those didn't come up in my local
tests it's mostly guesswork.
Rest is the same!
Reviewers: morehouse, hctim, eugenis, vitalybuka, dyung, hans
Reviewed By: morehouse, dyung, hans
Subscribers: srhines, mgorny, delcypher, jfb, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D63831
llvm-svn: 364547
Makes the build fail with e.g.
llvm/projects/compiler-rt/lib/scudo/standalone/wrappers_c.inc:20:68: error:
declaration of 'void* calloc(size_t, size_t)' has a different exception
specifier
INTERFACE WEAK void *SCUDO_PREFIX(calloc)(size_t nmemb, size_t size) {
^
See llvm-commits thread.
> Summary:
> This CL adds C & C++ wrappers and associated tests. Those use default
> configurations for a Scudo combined allocator that will likely be
> tweaked in the future.
>
> This is the final CL required to have a functional C & C++ allocator
> based on Scudo.
>
> The structure I have chosen is to define the core C allocation
> primitives in an `.inc` file that can be customized through defines.
> This allows to easily have 2 (or more) sets of wrappers backed by
> different combined allocators, as demonstrated by the `Bionic`
> wrappers: one set for the "default" allocator, one set for the "svelte"
> allocator.
>
> Currently all the tests added have been gtests, but I am planning to
> add some more lit tests as well.
>
> Reviewers: morehouse, eugenis, vitalybuka, hctim, rengolin
>
> Reviewed By: morehouse
>
> Subscribers: srhines, mgorny, delcypher, jfb, #sanitizers, llvm-commits
>
> Tags: #llvm, #sanitizers
>
> Differential Revision: https://reviews.llvm.org/D63612
llvm-svn: 364400
Summary:
This CL adds C & C++ wrappers and associated tests. Those use default
configurations for a Scudo combined allocator that will likely be
tweaked in the future.
This is the final CL required to have a functional C & C++ allocator
based on Scudo.
The structure I have chosen is to define the core C allocation
primitives in an `.inc` file that can be customized through defines.
This allows to easily have 2 (or more) sets of wrappers backed by
different combined allocators, as demonstrated by the `Bionic`
wrappers: one set for the "default" allocator, one set for the "svelte"
allocator.
Currently all the tests added have been gtests, but I am planning to
add some more lit tests as well.
Reviewers: morehouse, eugenis, vitalybuka, hctim, rengolin
Reviewed By: morehouse
Subscribers: srhines, mgorny, delcypher, jfb, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D63612
llvm-svn: 364332
Peter Collingbourne