Previously, ASan would produce reports like this:
ERROR: AddressSanitizer: breakpoint on unknown address 0x000000000000 (pc 0x7fffdd7c5e86 ...)
This is unhelpful, because the developer may think this is a null
pointer dereference, and not a breakpoint exception on some PC.
The cause was that SignalContext::GetAddress would read the
ExceptionInformation array to retreive an address for any kind of
exception. That data is only available for access violation exceptions.
This changes it to be conditional on the exception type, and to use the
PC otherwise.
I added a variety of tests for common exception types:
- int div zero
- breakpoint
- ud2a / illegal instruction
- SSE misalignment
I also tightened up IsMemoryAccess and GetWriteFlag to check the
ExceptionCode rather than looking at ExceptionInformation[1] directly.
Differential Revision: https://reviews.llvm.org/D92344
As discussed in the review for D87120 (specifically at
https://reviews.llvm.org/D87120#inline-831939), clean up PrintModuleMap
and DumpProcessMap usage differences. The former is only implemented for
Mac OSX, whereas the latter is implemented for all OSes. The former is
called by asan and tsan, and the latter by hwasan and now memprof, under
the same option. Simply rename the PrintModuleMap implementation for Mac
to DumpProcessMap, remove other empty PrintModuleMap implementations,
and convert asan/tsan to new name. The existing posix DumpProcessMap is
disabled for SANITIZER_MAC.
Differential Revision: https://reviews.llvm.org/D89630
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
Summary:
This change introduces the `Symbolizer::GetEnvP()` method that returns a
pointer to environment array used for spawning the symbolizer process.
The motivation is to allow implementations to customise the environment
if required. The default implementation just returns
`__sanitizer::GetEnviron()` which (provided it's implemented) should
preserve the existing behaviours of the various implementations.
This change has been plumbed through the `internal_spawn(...)` and
`StartSubprocess(...)` process spawning implementations.
For the `StartSubprocess()` implementation we need to call `execve()`
rather than `execv()` to pass the environment. However, it appears that
`internal_execve(...)` exists in sanitizer_common so this patch use that
which seems like a nice clean up.
Support in the Windows implementation of
`SymbolizerProcess:StartSymbolizerSubprocess()` has not been added
because the Windows sanitizer runtime doesn't implement `GetEnviron()`.
rdar://problem/58789439
Reviewers: kubamracek, yln, dvyukov, vitalybuka, eugenis, phosek, aizatsky, rnk
Subscribers: #sanitizers, llvm-commits
Tags: #sanitizers
Differential Revision: https://reviews.llvm.org/D76666
Summary:
Instead of hand-crafting an offset into the structure returned by
dlopen(3) to get at the link map, use the documented API. This is
described in dlinfo(3): by calling it with `RTLD_DI_LINKMAP`, the
dynamic linker ensures the right address is returned.
This is a recommit of 92e267a94d, with
dlinfo(3) expliclity being referenced only for FreeBSD, non-Android
Linux, NetBSD and Solaris. Other OSes will have to add their own
implementation.
Reviewers: devnexen, emaste, MaskRay, krytarowski
Reviewed By: krytarowski
Subscribers: krytarowski, vitalybuka, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73990
Summary:
Instead of hand-crafting an offset into the structure returned by
dlopen(3) to get at the link map, use the documented API. This is
described in dlinfo(3): by calling it with `RTLD_DI_LINKMAP`, the
dynamic linker ensures the right address is returned.
Reviewers: devnexen, emaste, MaskRay, krytarowski
Reviewed By: krytarowski
Subscribers: krytarowski, vitalybuka, #sanitizers, llvm-commits
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D73990
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
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
- Unless explicit configuration, using FreeBSD super pages feature for shadow mapping.
- asan only for now.
Reviewers: dim, emaste, vitalybuka
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D65851
llvm-svn: 370008
in madvise mode, the shadow pages will be migrated only via madvise explicit calls.
Reviewers: vitalybuka
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D65775
llvm-svn: 368090
See https://reviews.llvm.org/D58620 for discussion, and for the commands
I ran. In addition I also ran
for f in $(svn diff | diffstat | grep .cc | cut -f 2 -d ' '); do rg $f . ; done
and manually updated (many) references to renamed files found by that.
llvm-svn: 367463
Reid Kleckner