[asan] Reset stack bounds of context

ClearShadowMemoryForContextStack assumes that context contains the stack
bounds. This is not true for a context from getcontext or oucp of
swapcontext.

Reviewed

[asan] Reset stack bounds of context

ClearShadowMemoryForContextStack assumes that context contains the stack
bounds. This is not true for a context from getcontext or oucp of
swapcontext.

Reviewed By: kstoimenov

Differential Revision: https://reviews.llvm.org/D130218

show more ...

[asan] Always skip first object from dl_iterate_phdr

All platforms return the main executable as the first dl_phdr_info.
FreeBSD, NetBSD, Solaris, and Linux-musl place the executable name
in the dlp

[asan] Always skip first object from dl_iterate_phdr

All platforms return the main executable as the first dl_phdr_info.
FreeBSD, NetBSD, Solaris, and Linux-musl place the executable name
in the dlpi_name field of this entry. It appears that only Linux-glibc
uses the empty string.

To make this work generically on all platforms, unconditionally
skip the first object (like is currently done for FreeBSD and NetBSD).
This fixes first DSO detection on Linux-musl. It also would likely
fix detection on Solaris/Illumos if it were to gain PIE support
(since dlpi_addr would not be NULL).

Additionally, only skip the Linux VDSO on linux.

Finally, use the empty string as the "seen first dl_phdr_info"
marker rather than (char *)-1. If there was no other object, we
would try to dereference it for a string comparison.

Reviewed By: MaskRay, vitalybuka

Differential Revision: https://reviews.llvm.org/D119515

show more ...

Revert "[asan] Always skip first object from dl_iterate_phdr"

This reverts commit d75a5650dbdc595f836db4711f2a480f87243593.
Breaks asan_dlopen_test.cpp on several bots, see comments on
https://revie

Revert "[asan] Always skip first object from dl_iterate_phdr"

This reverts commit d75a5650dbdc595f836db4711f2a480f87243593.
Breaks asan_dlopen_test.cpp on several bots, see comments on
https://reviews.llvm.org/D119515

show more ...

[asan] Always skip first object from dl_iterate_phdr

All platforms return the main executable as the first dl_phdr_info.
FreeBSD, NetBSD, Solaris, and Linux-musl place the executable name
in the dlp

[asan] Always skip first object from dl_iterate_phdr

All platforms return the main executable as the first dl_phdr_info.
FreeBSD, NetBSD, Solaris, and Linux-musl place the executable name
in the dlpi_name field of this entry. It appears that only Linux-glibc
uses the empty string.

To make this work generically on all platforms, unconditionally skip the first
object (like is currently done for FreeBSD and NetBSD). This fixes first DSO
detection on Linux-musl with clang -shared-libsan/-shared-libasan and GCC's
default. It also would likely fix detection on Solaris/Illumos if it were to
gain PIE support (since dlpi_addr would not be NULL).

Additionally, only skip the Linux VDSO on linux.

Finally, use the empty string as the "seen first dl_phdr_info"
marker rather than (char *)-1. If there was no other object, we
would try to dereference it for a string comparison.

Reviewed By: MaskRay, vitalybuka

Differential Revision: https://reviews.llvm.org/D119515

show more ...

[ASan] Renamed SHADOW_XYZ to ASAN_SHADOW_XYZ.

Follow up from D115271.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D115293

Fix -Wformat warnings reported by GCC.

Differential Revision: https://reviews.llvm.org/D113099

[asan][memprof] Declare _DYNAMIC and fix -Wparentheses

Declare `extern ElfW(Dyn) _DYNAMIC[];` so that it will trivially work on musl.

[compiler-rt][asan] decommit shadow memory for unmaps in fuchsia.

This CL allows asan allocator in fuchsia to decommit shadow memory
for memory allocated using mmap.

Big allocations in asan end up

[compiler-rt][asan] decommit shadow memory for unmaps in fuchsia.

This CL allows asan allocator in fuchsia to decommit shadow memory
for memory allocated using mmap.

Big allocations in asan end up being allocated via `mmap` and freed with
`munmap`. However, when that memory is freed, asan returns the
corresponding shadow memory back to the OS via a call to
`ReleaseMemoryPagesToOs`.

In fuchsia, `ReleaseMemoryPagesToOs` is a no-op: to be able to free
memory back to the OS, you have to hold a handle to the vmo you want to
modify, which is tricky at the ReleaseMemoryPagesToOs level as that
function is not exclusively used for shadow memory.

The function `__sanitizer_fill_shadow` fills a given shadow memory range
with a specific value, and if that value is 0 (unpoison) and the memory
range is bigger than a threshold parameter, it will decommit that memory
if it is all zeroes.

This CL modifies the `FlushUnneededASanShadowMemory` function in
`asan_poisoning.cpp` to add a call to `__sanitizer_fill_shadow` with
value and threshold = 0. This way, all the unneeded shadow memory gets
returned back to the OS.

A test for this behavior can be found in fxrev.dev/391974

Differential Revision: https://reviews.llvm.org/D80355

Change-Id: Id6dd85693e78a222f0329d5b2201e0da753e01c0

show more ...

[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.

[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

show more ...

compiler-rt: Rename .cc file in lib/asan to .cpp

Like r367463, but for asan.

llvm-svn: 367558