This revision is a part of a series of patches extending
AddressSanitizer C++ container overflow detection capabilities by adding
annotations, similar to those existing in std::vector, to std::string
and std::deque collections. These changes allow ASan to detect cases
when the instrumented program accesses memory which is internally
allocated by the collection but is still not in-use (accesses before or
after the stored elements for std::deque, or between the size and
capacity bounds for std::string).
The motivation for the research and those changes was a bug, found by
Trail of Bits, in a real code where an out-of-bounds read could happen
as two strings were compared via a std::equals function that took
iter1_begin, iter1_end, iter2_begin iterators (with a custom comparison
function). When object iter1 was longer than iter2, read out-of-bounds
on iter2 could happen. Container sanitization would detect it.
This revision adds a new compiler-rt ASan sanitization API function
sanitizer_annotate_double_ended_contiguous_container necessary to
sanitize/annotate double ended contiguous containers. Note that that
function annotates a single contiguous memory buffer (for example the
std::deque's internal chunk). Such containers have the beginning of
allocated memory block, beginning of the container in-use data, end of
the container's in-use data and the end of the allocated memory block.
This also adds a new API function to verify if a double ended contiguous
container is correctly annotated
(__sanitizer_verify_double_ended_contiguous_container).
Since we do not modify the ASan's shadow memory encoding values, the
capability of sanitizing/annotating a prefix of the internal contiguous
memory buffer is limited – up to SHADOW_GRANULARITY-1 bytes may not be
poisoned before the container's in-use data. This can cause false
negatives (situations when ASan will not detect memory corruption in
those areas).
On the other hand, API function interfaces are designed to work even if
this caveat would not exist. Therefore implementations using those
functions will poison every byte correctly, if only ASan (and
compiler-rt) is extended to support it. In other words, if ASan was
modified to support annotating/poisoning of objects lying on addresses
unaligned to SHADOW_GRANULARITY (so e.g. prefixes of those blocks),
which would require changing its shadow memory encoding, this would not
require any changes in the libcxx std::string/deque code which is added
in further commits of this patch series.
If you have any questions, please email:
advenam.tacet@trailofbits.comdisconnect3d@trailofbits.com
Differential Revision: https://reviews.llvm.org/D132090
Add a new interface __sanitizer_get_report_path which will return the
full path to the report file if __sanitizer_set_report_path was
previously called (otherwise it returns null). This is useful in
particular for memory profiling handlers to access the path which
was specified at compile time (and passed down via
__memprof_profile_filename), including the pid added to the path when
the file is opened.
There wasn't a test for __sanitizer_set_report_path, so I added one
which additionally tests the new interface.
Differential Revision: https://reviews.llvm.org/D91765
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary:
Fixes https://github.com/google/sanitizers/issues/788/, a deadlock
caused by multiple crashes happening at the same time. Before printing
a crash report, we now test and set an atomic flag. If the flag was
already set, the crash handler returns immediately.
Reviewers: kcc
Reviewed By: kcc
Subscribers: llvm-commits, kubamracek
Differential Revision: https://reviews.llvm.org/D46277
llvm-svn: 331310
Summary:
Purging allocator quarantine and returning memory to OS might be desired
between fuzzer iterations since, most likely, the quarantine is not
going to catch bugs in the code under fuzz, but reducing RSS might
significantly prolong the fuzzing session.
Reviewers: cryptoad
Subscribers: kubamracek, llvm-commits
Differential Revision: https://reviews.llvm.org/D39153
llvm-svn: 316347
Add support for weak hooks on Windows, as we do on Linux and Darwin.
As we use the macro: `SANITIZER_INTERFACE_WEAK_DEF()` it was not necessary to
modify the header file: `sanitizer_common_interceptors.h`.
After this diff, many tests were fixed for libFuzzer.
Differential Revision: https://reviews.llvm.org/D29562
llvm-svn: 294409
Add a new auxiliary file to each sanitizer: sanitizer_interface.inc, listing all
the functions exported, with the macros: INTERFACE_FUNCTION() and
INTERFACE_WEAK_FUNCTION().
So, when we need to define or repeat a procedure for each function in the
sanitizer's interface, we can define the macros and include that header.
In particular, these files are needed for Windows, in the nexts commits.
Also, this files could replace the existing files: weak_symbols.txt for Apple.
Instead of reading weak_symbols.txt to get the list of weak symbols, we could
read the file sanitizer_interface.inc and consider all the symbols included with
the macro INTERFACE_WEAK_FUNCTION(Name).
In this commit, I only include these files to the sanitizers that work on
Windows. We could do the same for the rest of the sanitizers when needed.
I updated tests for: Linux, Darwin and Windows. If a new function is exported
but is not present in the interface list, the tests
"interface_symbols_[darwin|windows|linux].c" fail.
Also, I remove the comments: "/* OPTIONAL */" which are not required any more,
because we use the macro: INTERFACE_WEAK_FUNCTION() for weak functions.
Differential Revision: https://reviews.llvm.org/D29148
llvm-svn: 293682
Advenam Tacet