Please note that that this code is not used. It will be connected at some point when the rest of the code is ready.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D139464
This came up during review of D139464. Looks like this filed is always set to false to it is basically unused.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D139654
In that case it is very likely that there will be a tag mismatch anyway.
We handle the case that the pointer belongs to neither of the allocators
by getting a nullptr from allocator.GetBlockBegin.
Reviewed By: hctim, eugenis
Differential Revision: https://reviews.llvm.org/D108383
Fixes a regression when the allocator is disabled, and a dirty
allocation is re-used. This only occurs when the allocator is disabled,
so a test-only fix, but still necessary.
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D108650
In that case it is very likely that there will be a tag mismatch anyway.
We handle the case that the pointer belongs to neither of the allocators
by getting a nullptr from allocator.GetBlockBegin.
Reviewed By: hctim, eugenis
Differential Revision: https://reviews.llvm.org/D108383
The shadow for a short granule is stored in the last byte of the
granule. Currently, if there's a tail-overwrite report (a
buffer-overflow-write in uninstrumented code), we report the shadow byte
as a mismatch against the magic.
Fix this bug by slapping the shadow into the expected value. This also
makes sure that if the uninstrumented WRITE does clobber the shadow
byte, it reports the shadow was actually clobbered as well.
Reviewed By: eugenis, fmayer
Differential Revision: https://reviews.llvm.org/D107938
Before this change we were locking the StackDepot in the fork()
interceptor. This results in a deadlock when allocator functions are
used in a pthread_atfork() callback.
Instead, set up a pthread_atfork() callback at init that locks/unlocks
both StackDepot and the allocator. Since our callback is set up very
early, the pre-fork callback is executed late, and both post-fork ones
are executed early, which works perfect for us.
Differential Revision: https://reviews.llvm.org/D108063
This moves logic for setting kAliasRegionStart into hwasan_allocator.cpp
so other platforms that do not support aliasing mode will not need to define
kAliasRegionStart.
Differential Revision: https://reviews.llvm.org/D105725
Short granule tags as poison cause a UaF to read the referenced
memory to retrieve the tag, and means we do not detect the UaF
if the last granule's tag is still around.
This only increases the change of not catching a UaF from
0.39 % (1 / 256) to 0.42 % (1 / (256 - 17)).
Reviewed By: eugenis
Differential Revision: https://reviews.llvm.org/D104304
Userspace page aliasing allows us to use middle pointer bits for tags
without untagging them before syscalls or accesses. This should enable
easier experimentation with HWASan on x86_64 platforms.
Currently stack, global, and secondary heap tagging are unsupported.
Only primary heap allocations get tagged.
Note that aliasing mode will not work properly in the presence of
fork(), since heap memory will be shared between the parent and child
processes. This mode is non-ideal; we expect Intel LAM to enable full
HWASan support on x86_64 in the future.
Reviewed By: vitalybuka, eugenis
Differential Revision: https://reviews.llvm.org/D98875
Userspace page aliasing allows us to use middle pointer bits for tags
without untagging them before syscalls or accesses. This should enable
easier experimentation with HWASan on x86_64 platforms.
Currently stack, global, and secondary heap tagging are unsupported.
Only primary heap allocations get tagged.
Note that aliasing mode will not work properly in the presence of
fork(), since heap memory will be shared between the parent and child
processes. This mode is non-ideal; we expect Intel LAM to enable full
HWASan support on x86_64 in the future.
Reviewed By: vitalybuka, eugenis
Differential Revision: https://reviews.llvm.org/D98875
Summary:
This has been an experiment with late malloc interposition, made
possible by a non-standard feature of the Android dynamic loader.
Reviewers: pcc, mmalcomson
Subscribers: srhines, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D69199
llvm-svn: 375296
A short granule is a granule of size between 1 and `TG-1` bytes. The size
of a short granule is stored at the location in shadow memory where the
granule's tag is normally stored, while the granule's actual tag is stored
in the last byte of the granule. This means that in order to verify that a
pointer tag matches a memory tag, HWASAN must check for two possibilities:
* the pointer tag is equal to the memory tag in shadow memory, or
* the shadow memory tag is actually a short granule size, the value being loaded
is in bounds of the granule and the pointer tag is equal to the last byte of
the granule.
Pointer tags between 1 to `TG-1` are possible and are as likely as any other
tag. This means that these tags in memory have two interpretations: the full
tag interpretation (where the pointer tag is between 1 and `TG-1` and the
last byte of the granule is ordinary data) and the short tag interpretation
(where the pointer tag is stored in the granule).
When HWASAN detects an error near a memory tag between 1 and `TG-1`, it
will show both the memory tag and the last byte of the granule. Currently,
it is up to the user to disambiguate the two possibilities.
Because this functionality obsoletes the right aligned heap feature of
the HWASAN memory allocator (and because we can no longer easily test
it), the feature is removed.
Also update the documentation to cover both short granule tags and
outlined checks.
Differential Revision: https://reviews.llvm.org/D63908
llvm-svn: 365551
As discussed elsewhere: LLVM uses cpp as its C++ source extension; the
sanitizers should too. This updates files in hwasan.
Patch generated by
for f in lib/hwasan/*.cc ; do svn mv $f ${f%.cc}.cpp; done
followed by
for f in lib/hwasan/*.cpp ; do sed -i '' -e '1s/\.cc -/.cpp /' $f; done
CMakeLists.txt updated manually.
Differential Revision: https://reviews.llvm.org/D58620
llvm-svn: 354989
