Commit Graph

22 Commits

Author SHA1 Message Date
Nico Weber 0e92cbd6a6 Revert "[sanitizer] Simplify GetTls with dl_iterate_phdr on Linux"
This reverts commit ec575e3b0a.
Still doesn't work, see https://crbug.com/1196037
2021-04-05 19:00:18 -04:00
Fangrui Song ec575e3b0a [sanitizer] Simplify GetTls with dl_iterate_phdr on Linux
This was reverted by f176803ef1 due to
Ubuntu 16.04 x86-64 glibc 2.23 problems.
This commit additionally calls `__tls_get_addr({modid,0})` to work around the
dlpi_tls_data==NULL issues for glibc<2.25
(https://sourceware.org/bugzilla/show_bug.cgi?id=19826)

GetTls is the range of

* thread control block and optional TLS_PRE_TCB_SIZE
* static TLS blocks plus static TLS surplus

On glibc, lsan requires the range to include
`pthread::{specific_1stblock,specific}` so that allocations only referenced by
`pthread_setspecific` can be scanned.

This patch uses `dl_iterate_phdr` to collect TLS blocks. Find the one
with `dlpi_tls_modid==1` as one of the initially loaded module, then find
consecutive ranges. The boundaries give us addr and size.

This allows us to drop the glibc internal `_dl_get_tls_static_info` and
`InitTlsSize` entirely. Use the simplified method with non-Android Linux for
now, but in theory this can be used with *BSD and potentially other ELF OSes.

This simplification enables D99566 for TLS Variant I architectures.

See https://reviews.llvm.org/D93972#2480556 for analysis on GetTls usage
across various sanitizers.

Differential Revision: https://reviews.llvm.org/D98926
2021-04-04 15:35:53 -07:00
Nico Weber f176803ef1 Revert "[sanitizer] Simplify GetTls with dl_iterate_phdr"
This reverts commit 9be8f8b34d.
This breaks tsan on Ubuntu 16.04:

    $ cat tiny_race.c
    #include <pthread.h>
    int Global;
    void *Thread1(void *x) {
      Global = 42;
      return x;
    }
    int main() {
      pthread_t t;
      pthread_create(&t, NULL, Thread1, NULL);
      Global = 43;
      pthread_join(t, NULL);
      return Global;
    }
    $ out/gn/bin/clang -fsanitize=thread -g -O1 tiny_race.c --sysroot ~/src/chrome/src/build/linux/debian_sid_amd64-sysroot/
    $ docker run -v $PWD:/foo ubuntu:xenial /foo/a.out
    FATAL: ThreadSanitizer CHECK failed: ../../compiler-rt/lib/tsan/rtl/tsan_platform_linux.cpp:447 "((thr_beg)) >= ((tls_addr))" (0x7fddd76beb80, 0xfffffffffffff980)
        #0 <null> <null> (a.out+0x4960b6)
        #1 <null> <null> (a.out+0x4b677f)
        #2 <null> <null> (a.out+0x49cf94)
        #3 <null> <null> (a.out+0x499bd2)
        #4 <null> <null> (a.out+0x42aaf1)
        #5 <null> <null> (libpthread.so.0+0x76b9)
        #6 <null> <null> (libc.so.6+0x1074dc)

(Get the sysroot from here: https://commondatastorage.googleapis.com/chrome-linux-sysroot/toolchain/500976182686961e34974ea7bdc0a21fca32be06/debian_sid_amd64_sysroot.tar.xz)

Also reverts follow-on commits:
This reverts commit 58c62fd976.
This reverts commit 31e541e375.
2021-04-02 18:19:17 -04:00
Fangrui Song 9be8f8b34d [sanitizer] Simplify GetTls with dl_iterate_phdr
GetTls is the range of

* thread control block and optional TLS_PRE_TCB_SIZE
* static TLS blocks plus static TLS surplus

On glibc, lsan requires the range to include
`pthread::{specific_1stblock,specific}` so that allocations only referenced by
`pthread_setspecific` can be scanned.

This patch uses `dl_iterate_phdr` to collect TLS ranges. Find the one
with `dlpi_tls_modid==1` as one of the initially loaded module, then find
consecutive ranges. The boundaries give us addr and size.

This allows us to drop the glibc internal `_dl_get_tls_static_info` and
`InitTlsSize` entirely. Use the simplified method with non-Android Linux for
now, but in theory this can be used with *BSD and potentially other ELF OSes.

In the future, we can move `ThreadDescriptorSize` code to lsan (and consider
intercepting `pthread_setspecific`) to avoid hacks in generic code.

See https://reviews.llvm.org/D93972#2480556 for analysis on GetTls usage
across various sanitizers.

Differential Revision: https://reviews.llvm.org/D98926
2021-03-25 21:55:27 -07:00
Vitaly Buka e0dadf3de2 [sanitizer] Remove max_len parameter from InternalScopedString
InternalScopedString uses InternalMmapVector internally
so it can be resized dynamically as needed.

Reviewed By: eugenis

Differential Revision: https://reviews.llvm.org/D98751
2021-03-17 16:57:09 -07:00
Fangrui Song 2d7fd38cf7 [sanitizers] Remove unneeded MaybeCall*DefaultOptions() and nullptr checks
D28596 added SANITIZER_INTERFACE_WEAK_DEF which can guarantee `*_default_options` are always defined.
The weak attributes on the `__{asan,lsan,msan,ubsan}_default_options` declarations can thus be removed.

`MaybeCall*DefaultOptions` no longer need nullptr checks, so their call sites can just be replaced by `__*_default_options`.

Reviewed By: #sanitizers, vitalybuka

Differential Revision: https://reviews.llvm.org/D87175
2020-09-08 10:12:05 -07:00
Teresa Johnson 5d2be1a188 [compiler-rt][asan][hwasan] Refactor shadow setup into sanitizer_common (NFCI)
Summary:
This refactors some common support related to shadow memory setup from
asan and hwasan into sanitizer_common. This should not only reduce code
duplication but also make these facilities available for new compiler-rt
uses (e.g. heap profiling).

In most cases the separate copies of the code were either identical, or
at least functionally identical. A few notes:

In ProtectGap, the asan version checked the address against an upper
bound (kZeroBaseMaxShadowStart, which is (2^18). I have created a copy
of kZeroBaseMaxShadowStart in hwasan_mapping.h, with the same value, as
it isn't clear why that code should not do the same check. If it
shouldn't, I can remove this and guard this check so that it only
happens for asan.

In asan's InitializeShadowMemory, in the dynamic shadow case it was
setting __asan_shadow_memory_dynamic_address to 0 (which then sets both
macro SHADOW_OFFSET as well as macro kLowShadowBeg to 0) before calling
FindDynamicShadowStart(). AFAICT this is only needed because
FindDynamicShadowStart utilizes kHighShadowEnd to
get the shadow size, and kHighShadowEnd is a macro invoking
MEM_TO_SHADOW(kHighMemEnd) which in turn invokes:
(((kHighMemEnd) >> SHADOW_SCALE) + (SHADOW_OFFSET))
I.e. it computes the shadow space needed by kHighMemEnd (the shift), and
adds the offset. Since we only want the shadow space here, the earlier
setting of SHADOW_OFFSET to 0 via __asan_shadow_memory_dynamic_address
accomplishes this. In the hwasan version, it simply gets the shadow
space via "MemToShadowSize(kHighMemEnd)", where MemToShadowSize just
does the shift. I've simplified the asan handling to do the same
thing, and therefore was able to remove the setting of the SHADOW_OFFSET
via __asan_shadow_memory_dynamic_address to 0.

Reviewers: vitalybuka, kcc, eugenis

Subscribers: dberris, #sanitizers, llvm-commits, davidxl

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D83247
2020-07-16 11:47:05 -07:00
Mitch Phillips e26b25f8b1 [HWASan] Add sizeof(global) in report even if symbols missing.
Summary: Refactor the current global header iteration to be callback-based, and add a feature that reports the size of the global variable during reporting. This allows binaries without symbols to still report the size of the global variable, which is always available in the HWASan globals PT_NOTE metadata.

Reviewers: eugenis, pcc

Reviewed By: pcc

Subscribers: mgorny, llvm-commits, #sanitizers

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D80599
2020-06-09 13:02:13 -07:00
Evgenii Stepanov eaea9ed835 [hwasan] Reset current thread pointer on thread exit.
Summary:
This is necessary to handle calls to free() after __hwasan_thread_exit,
which is possible in glibc.

Also, add a null check to GetCurrentThread, otherwise the logic in
GetThreadByBufferAddress turns it into a non-null value. This means that
all of the checks for GetCurrentThread() != nullptr do not have any
effect at all right now!

Reviewers: pcc, hctim

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers

Differential Revision: https://reviews.llvm.org/D79608
2020-05-08 10:31:25 -07:00
Peter Collingbourne 9b9c68a2d6 hwasan: Remove dead code. NFCI.
Differential Revision: https://reviews.llvm.org/D72896
2020-01-17 15:12:38 -08:00
Evgeniy Stepanov d5282dfc41 libhwasan initialisation include kernel syscall ABI relaxation
Summary:
Until now AArch64 development has been on patched kernels that have an always
on relaxed syscall ABI where tagged pointers are accepted.
The patches that have gone into the mainline kernel rely on each process opting
in to this relaxed ABI.

This commit adds code to choose that ABI into __hwasan_init.

The idea has already been agreed with one of the hwasan developers
(http://lists.llvm.org/pipermail/llvm-dev/2019-September/135328.html).

The patch ignores failures of `EINVAL` for Android, since there are older versions of the Android kernel that don't require this `prctl` or even have the relevant values.  Avoiding EINVAL will let the library run on them.

I've tested this on an AArch64 VM running a kernel that requires this
prctl, having compiled both with clang and gcc.

Patch by Matthew Malcomson.

Reviewers: eugenis, kcc, pcc

Reviewed By: eugenis

Subscribers: srhines, kristof.beyls, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D68794

llvm-svn: 375166
2019-10-17 20:32:54 +00:00
Peter Collingbourne b2e7b85468 hwasan: Align n_namesz and n_descsz to 4 when reading notes.
There is no requirement for the producer of a note to include the note
alignment in these fields. As a result we can end up missing the HWASAN note
if one of the other notes in the binary has the alignment missing.

Differential Revision: https://reviews.llvm.org/D66692

llvm-svn: 369826
2019-08-23 23:33:26 +00:00
Peter Collingbourne 3a9059effb hwasan: Add a code model check for tagged globals.
See D65364 for the code model requirements for tagged globals. Because
of the relocations used these requirements cannot be checked at link
time so they must be checked at runtime.

Differential Revision: https://reviews.llvm.org/D65968

llvm-svn: 368351
2019-08-08 21:40:00 +00:00
Peter Collingbourne 0930643ff6 hwasan: Instrument globals.
Globals are instrumented by adding a pointer tag to their symbol values
and emitting metadata into a special section that allows the runtime to tag
their memory when the library is loaded.

Due to order of initialization issues explained in more detail in the comments,
shadow initialization cannot happen during regular global initialization.
Instead, the location of the global section is marked using an ELF note,
and we require libc support for calling a function provided by the HWASAN
runtime when libraries are loaded and unloaded.

Based on ideas discussed with @evgeny777 in D56672.

Differential Revision: https://reviews.llvm.org/D65770

llvm-svn: 368102
2019-08-06 22:07:29 +00:00
Peter Collingbourne d11ea6518c hwasan: Teach the runtime to identify the local variable being accessed in UAR reports.
Each function's PC is recorded in the ring buffer. From there we can access
the function's local variables and reconstruct the tag of each one with the
help of the information printed by llvm-symbolizer's new FRAME command. We
can then find the variable that was likely being accessed by matching the
pointer's tag against the reconstructed tag.

Differential Revision: https://reviews.llvm.org/D63469

llvm-svn: 364607
2019-06-27 23:16:13 +00:00
Vitaly Buka 0b1ea8cb28 Improve error message when '=' is missing in {ASAN,...}_OPTIONS.
Summary:
It's handling isses as described here:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89832

Patch by Martin Liška.

Reviewers: kcc, vitalybuka

Reviewed By: vitalybuka

Subscribers: cryptoad, kubamracek

Differential Revision: https://reviews.llvm.org/D59876

llvm-svn: 363480
2019-06-15 01:37:14 +00:00
Julian Lettner 9fe3b4906f [NFC][Sanitizer] Make GetStackTrace a private method of BufferedStackTrace
GetStackTrace is a implementation detail of BufferedStackTrace. Make it
a private method.

Reviewed By: vitalybuka

Differential-Revision: https://reviews.llvm.org/D58753
llvm-svn: 355232
2019-03-01 22:10:49 +00:00
Evgeniy Stepanov ecb2c1fd5b [hwasan] Fix vfork handling with large stack limit.
Remove the maximum stack cleanup size check. With ulimit -s unlimited
main thread stack can be very large, but we don't really have a choice
other than cleaning all of it. It should be reasonably fast - hwasan
cleans large shadow ranges with a single madvise call.

This change fixes check-hwasan after ulimit -s unlimited.

llvm-svn: 355137
2019-02-28 20:43:24 +00:00
Julian Lettner a0884da62a [NFC][Sanitizer] Pull up GetStackTrace into sanitizer_common
We already independently declare GetStackTrace in all (except TSan)
sanitizer runtime headers. Lets move it to sanitizer_stacktrace.h to
have one canonical way to fill in a BufferedStackFrame. Also enables us
to use it in sanitizer_common itself.

This patch defines GetStackTrace for TSan and moves the function from
ubsan_diag.cc to ubsan_diag_standalone.cc to avoid duplicate symbols
for the UBSan-ASan runtime.

Other than that this patch just moves the code out of headers and into
the correct namespace.

Reviewers: vitalybuka

Differential Revision: https://reviews.llvm.org/D58651

llvm-svn: 355039
2019-02-27 22:16:02 +00:00
Evgeniy Stepanov f46a52b536 [hwasan, asan] Intercept vfork.
Summary:
Intercept vfork on arm, aarch64, i386 and x86_64.

Reviewers: pcc, vitalybuka

Subscribers: kubamracek, mgorny, javed.absar, krytarowski, kristof.beyls, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D58533

llvm-svn: 355030
2019-02-27 21:11:50 +00:00
Julian Lettner 46e1b16e36 [NFC][Sanitizer] Hard-code fast/slow unwinder at call site
Also assert that the caller always gets what it requested.

This purely mechanical change simplifies future refactorings and
eventual removal of BufferedStackTrace::Unwind.

Reviewers: vitalybuka

Differential Revision: https://reviews.llvm.org/D58557

llvm-svn: 355022
2019-02-27 20:01:04 +00:00
Nico Weber e3b6d11038 hwasan: Rename source files from cc to cpp
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
2019-02-27 15:44:03 +00:00