Commit Graph

6 Commits

Author SHA1 Message Date
Mitch Phillips 8e167f66b2 [GWP-ASan] Add version header.
Adds magic version header to AllocatorState. This can be used by
out-of-process crash handlers, like Crashpad on Fuchsia, to do offline
reconstruction of GWP-ASan crash metadata.

Crashpad on Fuchsia is intending on dumping the AllocationMetadata pool
and the AllocatorState directly into the minidump. Then, using the
version number, they can unpack the data on serverside using a versioned
unpack tool.

Also add some asserts to make sure the version number gets bumped if the
internal structs get changed.

Reviewed By: eugenis, mcgrathr

Differential Revision: https://reviews.llvm.org/D106690
2021-07-29 14:52:37 -07:00
Mitch Phillips e78b64df98 [Scudo] Use GWP-ASan's aligned allocations and fixup postalloc hooks.
This patch does a few cleanup things:
 1. The non-standalone scudo has a problem where GWP-ASan allocations
 may not meet alignment requirements where Scudo was requested to have
 alignment >= 16. Use the new GWP-ASan API to fix this.
 2. The standalone variant loses some debugging information inside of
 GWP-ASan because we ask GWP-ASan to allocate an aligned size in the
 frontend. This means reports end up with 'UaF on a 16-byte allocation'
 for a 1-byte allocation with 16-byte alignment. Also use the new API to
 fix this.
 3. Add post-alloc hooks for GWP-ASan intercepted allocations, and add
 stats tracking for GWP-ASan allocations.
 4. Add a small test that checks the alignment of the frontend
 allocator, so that it can be used under GWP-ASan torture mode.
 5. Add GWP-ASan torture mode as a testing configuration to catch these
 regressions.

Depends on D94830, D95889.

Reviewed By: cryptoad

Differential Revision: https://reviews.llvm.org/D95884
2021-05-10 12:56:18 -07:00
Mitch Phillips 3d8823b8e4 [GWP-ASan] Add aligned allocations.
Adds a new allocation API to GWP-ASan that handles size+alignment
restrictions.

Reviewed By: cryptoad, eugenis

Differential Revision: https://reviews.llvm.org/D94830
2021-02-08 11:22:29 -08:00
Mitch Phillips 0dcf3324cf Revert "[GWP-ASan] Add aligned allocations."
This reverts commit 9dc0676247.

Should not have been committed, was a bad rebase. Review still
continuing on D94830.
2021-02-02 14:46:25 -08:00
Mitch Phillips 9dc0676247 [GWP-ASan] Add aligned allocations.
Adds a new allocation API to GWP-ASan that handles size+alignment
restrictions.

Differential Revision: https://reviews.llvm.org/D94830
2021-02-02 14:44:35 -08:00
Mitch Phillips a62586846f [GWP-ASan] Crash Handler API.
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
2020-02-05 15:39:17 -08:00