Julian Lettner 99c9d7bd63 Reland "[ASan] Do not misrepresent high value address dereferences as null dereferences"
Updated: Removed offending TODO comment.

Dereferences with addresses above the 48-bit hardware addressable range
produce "invalid instruction" (instead of "invalid access") hardware
exceptions (there is no hardware address decoding logic for those bits),
and the address provided by this exception is the address of the
instruction (not the faulting address).  The kernel maps the "invalid
instruction" to SEGV, but fails to provide the real fault address.

Because of this ASan lies and says that those cases are null
dereferences.  This downgrades the severity of a found bug in terms of
security.  In the ASan signal handler, we can not provide the real
faulting address, but at least we can try not to lie.

rdar://50366151

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D68676

> llvm-svn: 374265

llvm-svn: 374384
2019-10-10 17:19:58 +00:00
..
2019-08-21 05:06:21 +00:00
2019-09-11 23:19:48 +00:00
2019-09-11 23:19:48 +00:00
2019-09-11 23:19:48 +00:00
2019-08-21 05:06:21 +00:00
2019-09-11 23:19:48 +00:00

AddressSanitizer RT
================================
This directory contains sources of the AddressSanitizer (ASan) runtime library.

Directory structure:
README.txt       : This file.
Makefile.mk      : File for make-based build.
CMakeLists.txt   : File for cmake-based build.
asan_*.{cc,h}    : Sources of the asan runtime library.
scripts/*        : Helper scripts.
tests/*          : ASan unit tests.

Also ASan runtime needs the following libraries:
lib/interception/      : Machinery used to intercept function calls.
lib/sanitizer_common/  : Code shared between various sanitizers.

ASan runtime currently also embeds part of LeakSanitizer runtime for
leak detection (lib/lsan/lsan_common.{cc,h}).

ASan runtime can only be built by CMake. You can run ASan tests
from the root of your CMake build tree:

make check-asan

For more instructions see:
https://github.com/google/sanitizers/wiki/AddressSanitizerHowToBuild