Commit Graph

7 Commits

Author SHA1 Message Date
Peter Collingbourne 21d50019ca scudo: Add support for diagnosing memory errors when memory tagging is enabled.
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
2020-04-17 17:26:30 -07:00
Kostya Kortchinsky 15754acc59 [scudo][standalone] Split logs on Android
Summary:
The function used to log on Android will cut the message past
a certain amount of characters, which mostly materializes when
dumping the size class map on OOM.

This change splits the log message at newline boundaries.

Reviewers: pcc, cferris, hctim, eugenis

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D78018
2020-04-14 11:29:57 -07:00
Kostya Kortchinsky a1f6ff2681 [scudo][standalone] Fix Android logging
Summary:
Zygote & children's stderr is lost, so use Bionic's provided allocation
free syslog function for `outputRaw`. Get rid of the mutex as it's not
vital and could cause issues with `fork`.

Reviewers: cferris, pcc, eugenis, hctim, morehouse

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D73561
2020-01-28 11:03:39 -08:00
Kostya Kortchinsky 561fa84477 [scudo][standalone] Allow sched_getaffinity to fail
Summary:
In some configuration, `sched_getaffinity` can fail. Some reasons for
that being the lack of `CAP_SYS_NICE` capability or some syscall
filtering and so on.

This should not be fatal to the allocator, so in this situation, we
will fallback to the `MaxTSDCount` value specified in the allocator
configuration.

Reviewers: cferris, eugenis, hctim, morehouse, pcc

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D73055
2020-01-21 11:18:18 -08:00
Peter Collingbourne c299d1981d scudo: Add initial memory tagging support.
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
2020-01-16 13:27:49 -08:00
Kostya Kortchinsky 8095449e68 [scudo][standalone] Minor corrections
Summary:
Few corrections with no functional change:
- replacing `%zd` with `%zu` all around: the values are unsigned
- prefer `MAP_ANONYMOUS` to `MAP_ANON` (it's deprecated)
- remove the unused `enum LinkerInitialized`
- mark a parameter as `UNUSED` in Fuchsia's `getRandom`
- correct the casing of a variable and use `nullptr` instead of 0 for
  pointers in `list.h`
- reorder some `typedef` to be consistent between `signed` and
  `unsigned`

Reviewers: eugenis, vitalybuka, morehouse, hctim

Reviewed By: vitalybuka, morehouse

Subscribers: delcypher, #sanitizers, llvm-commits

Tags: #llvm, #sanitizers

Differential Revision: https://reviews.llvm.org/D65660

llvm-svn: 368585
2019-08-12 15:35:09 +00:00
Nico Weber 6d46ebefb7 compiler-rt: Rename .cc file in lib/scudo/standalone to .cpp
Like r367463, but for scudo/standalone.

llvm-svn: 367568
2019-08-01 14:36:38 +00:00