335 Commits

Author SHA1 Message Date
Charlie Barto
53a81d4d26
Reland [asan][windows] Eliminate the static asan runtime on windows (#107899)
This reapplies 8fa66c6ca7272268747835a0e86805307b62399c ([asan][windows]
Eliminate the static asan runtime on windows) for a second time.

That PR bounced off the tests because it caused failures in the other
sanitizer runtimes, these have been fixed by only building interception,
sanitizer_common, and asan with /MD, and continuing to build the rest of
the runtimes with /MT. This does mean that any usage of the static
ubsan/fuzzer/etc runtimes will mean you're mixing different runtime
library linkages in the same app, the interception, sanitizer_common,
and asan runtimes are designed for this, however it does result in some
linker warnings.

Additionally, it turns out when building in release-mode with
LLVM_ENABLE_PDBs the build system forced /OPT:ICF. This totally breaks
asan's "new" method of doing "weak" functions on windows, and so
/OPT:NOICF was explicitly added to asan's link flags.

---------

Co-authored-by: Amy Wishnousky <amyw@microsoft.com>
2024-09-09 13:41:08 -07:00
Justin Stitt
76236fafda
[Clang] Overflow Pattern Exclusion - rename some patterns, enhance docs (#105709)
From @vitalybuka's review on
https://github.com/llvm/llvm-project/pull/104889:
- [x] remove unused variable in tests
- [x] rename `post-decr-while` --> `unsigned-post-decr-while`
- [x] split `add-overflow-test` into `add-unsigned-overflow-test` and
`add-signed-overflow-test`
- [x] be more clear about defaults within docs
- [x] add table to docs

Here's a screenshot of the rendered table so you don't have to build the
html docs yourself to inspect the layout:

![image](https://github.com/user-attachments/assets/5d3497c4-5f5a-4579-b29b-96a0fd192faa)


CCs: @vitalybuka

---------

Signed-off-by: Justin Stitt <justinstitt@google.com>
Co-authored-by: Vitaly Buka <vitalybuka@google.com>
2024-08-23 23:33:23 -07:00
Chris Apple
f77e8f765e
[clang][rtsan] Reland realtime sanitizer codegen and driver (#102622)
This reverts commit a1e9b7e646b76bf844e8a9a101ebd27de11992ff
This relands commit d010ec6af8162a8ae4e42d2cac5282f83db0ce07

No modifications from the original patch. It was determined that the
ubsan build failure was happening even after the revert, some examples:

https://lab.llvm.org/buildbot/#/builders/159/builds/4477 
https://lab.llvm.org/buildbot/#/builders/159/builds/4478 
https://lab.llvm.org/buildbot/#/builders/159/builds/4479
2024-08-23 08:16:52 -07:00
Chris Apple
a1e9b7e646
Revert "[clang][rtsan] Introduce realtime sanitizer codegen and drive… (#105744)
…r (#102622)"

This reverts commit d010ec6af8162a8ae4e42d2cac5282f83db0ce07.

Build failure: https://lab.llvm.org/buildbot/#/builders/159/builds/4466
2024-08-22 15:19:41 -07:00
Chris Apple
d010ec6af8
[clang][rtsan] Introduce realtime sanitizer codegen and driver (#102622)
Introduce the `-fsanitize=realtime` flag in clang driver

Plug in the RealtimeSanitizer PassManager pass in Codegen, and attribute
a function based on if it has the `[[clang::nonblocking]]` function
effect.
2024-08-22 14:08:24 -07:00
Justin Stitt
295fe0bd43
[Clang] Re-land Overflow Pattern Exclusions (#104889)
Introduce "-fsanitize-undefined-ignore-overflow-pattern=" which can
be used to disable sanitizer instrumentation for common overflow-dependent
code patterns.

For a wide selection of projects, proper overflow sanitization could
help catch bugs and solve security vulnerabilities. Unfortunately, in
some cases the integer overflow sanitizers are too noisy for their users
and are often left disabled. Providing users with a method to disable
sanitizer instrumentation of common patterns could mean more projects
actually utilize the sanitizers in the first place.

One such project that has opted to not use integer overflow (or
truncation) sanitizers is the Linux Kernel. There has been some
discussion[1] recently concerning mitigation strategies for unexpected
arithmetic overflow. This discussion is still ongoing and a succinct
article[2] accurately sums up the discussion. In summary, many Kernel
developers do not want to introduce more arithmetic wrappers when
most developers understand the code patterns as they are.

Patterns like:

  if (base + offset < base) { ... }

or

  while (i--) { ... }

or

  #define SOME -1UL

are extremely common in a code base like the Linux Kernel. It is
perhaps too much to ask of kernel developers to use arithmetic wrappers
in these cases. For example:

  while (wrapping_post_dec(i)) { ... }

which wraps some builtin would not fly. This would incur too many
changes to existing code; the code churn would be too much, at least too
much to justify turning on overflow sanitizers.

Currently, this commit tackles three pervasive idioms:

1. "if (a + b < a)" or some logically-equivalent re-ordering like "if (a > b + a)"
2. "while (i--)" (for unsigned) a post-decrement always overflows here
3. "-1UL, -2UL, etc" negation of unsigned constants will always overflow

The patterns that are excluded can be chosen from the following list:

- add-overflow-test
- post-decr-while
- negated-unsigned-const

These can be enabled with a comma-separated list:

  -fsanitize-undefined-ignore-overflow-pattern=add-overflow-test,negated-unsigned-const

"all" or "none" may also be used to specify that all patterns should be
excluded or that none should be.

[1] https://lore.kernel.org/all/202404291502.612E0A10@keescook/
[2] https://lwn.net/Articles/979747/

CCs: @efriedma-quic @kees @jyknight @fmayer @vitalybuka
Signed-off-by: Justin Stitt <justinstitt@google.com>
Co-authored-by: Bill Wendling <morbo@google.com>
2024-08-20 20:13:44 +00:00
Thurston Dang
e398da2b37 Revert "[Clang] Overflow Pattern Exclusions (#100272)"
This reverts commit 9a666deecb9ff6ca3a6b12e6c2877e19b74b54da.

Reason: broke buildbots

e.g., fork-ubsan.test started failing at
https://lab.llvm.org/buildbot/#/builders/66/builds/2819/steps/9/logs/stdio

  Clang :: CodeGen/compound-assign-overflow.c
  Clang :: CodeGen/sanitize-atomic-int-overflow.c
started failing with https://lab.llvm.org/buildbot/#/builders/52/builds/1570
2024-08-15 10:18:52 -07:00
Justin Stitt
9a666deecb
[Clang] Overflow Pattern Exclusions (#100272)
Introduce "-fsanitize-overflow-pattern-exclusion=" which can be used to
disable sanitizer instrumentation for common overflow-dependent code
patterns.

For a wide selection of projects, proper overflow sanitization could
help catch bugs and solve security vulnerabilities. Unfortunately, in
some cases the integer overflow sanitizers are too noisy for their users
and are often left disabled. Providing users with a method to disable
sanitizer instrumentation of common patterns could mean more projects
actually utilize the sanitizers in the first place.

One such project that has opted to not use integer overflow (or
truncation) sanitizers is the Linux Kernel. There has been some
discussion[1] recently concerning mitigation strategies for unexpected
arithmetic overflow. This discussion is still ongoing and a succinct
article[2] accurately sums up the discussion. In summary, many Kernel
developers do not want to introduce more arithmetic wrappers when
most developers understand the code patterns as they are.

Patterns like:

    if (base + offset < base) { ... }

or

    while (i--) { ... }

or

    #define SOME -1UL

are extremely common in a code base like the Linux Kernel. It is
perhaps too much to ask of kernel developers to use arithmetic wrappers
in these cases. For example:

    while (wrapping_post_dec(i)) { ... }

which wraps some builtin would not fly. This would incur too many
changes to existing code; the code churn would be too much, at least too
much to justify turning on overflow sanitizers.

Currently, this commit tackles three pervasive idioms:

1. "if (a + b < a)" or some logically-equivalent re-ordering like "if (a > b + a)"
2. "while (i--)" (for unsigned) a post-decrement always overflows here
3. "-1UL, -2UL, etc" negation of unsigned constants will always overflow

The patterns that are excluded can be chosen from the following list:

- add-overflow-test
- post-decr-while
- negated-unsigned-const

These can be enabled with a comma-separated list:

    -fsanitize-overflow-pattern-exclusion=add-overflow-test,negated-unsigned-const

"all" or "none" may also be used to specify that all patterns should be
excluded or that none should be.

[1] https://lore.kernel.org/all/202404291502.612E0A10@keescook/
[2] https://lwn.net/Articles/979747/

CCs: @efriedma-quic @kees @jyknight @fmayer @vitalybuka
Signed-off-by: Justin Stitt <justinstitt@google.com>
Co-authored-by: Bill Wendling <morbo@google.com>
2024-08-15 00:17:06 +00:00
Fangrui Song
9324c952e5 [Driver] -fsanitize=numerical: work with ubsan and support -shared-libsan
* `-fsanitize=numerical,undefined`: don't link in the ubsan standalone
  runtime.
* `-shared-libsan`: link against `libclang_rt.nsan.so`

The compiler-rt part will be properly fixed by #98415
2024-07-10 17:32:17 -07:00
Alexander Shaposhnikov
48f8130a49
[Clang][Sanitizers] Add numerical sanitizer (#93783)
Add plumbing for the numerical sanitizer on Clang's side.
2024-06-10 22:14:26 -07:00
Charlie Barto
0a93e9f2e2 Revert "[asan][windows] Eliminate the static asan runtime on windows (#93770)"
This reverts commit 8fa66c6ca7272268747835a0e86805307b62399c.
2024-05-30 11:41:44 -07:00
Charlie Barto
8fa66c6ca7
[asan][windows] Eliminate the static asan runtime on windows (#93770)
Re-Apply: 246234ac70faa1e3281a2bb83dfc4dd206a7d59c
Originally #81677

The static asan runtime on windows had various buggy hacks to ensure loaded dlls got the executable's copy of asan, these never worked all that well, so we have eliminated the static runtime altogether and made the dynamic runtime work for applications linking any flavor of the CRT.

Among other things this allows non-asan-instrumented applications to load asan-instrumented dlls that link against the static CRT.

Co-authored-by: Amy Wishnousky <amyw@microsoft.com>
2024-05-30 11:22:26 -07:00
Charlie Barto
10436aede2 Revert "[asan][windows] Eliminate the static asan runtime on windows (#81677)"
This reverts commit 246234ac70faa1e3281a2bb83dfc4dd206a7d59c.
2024-05-29 17:52:54 -07:00
Charlie Barto
246234ac70
[asan][windows] Eliminate the static asan runtime on windows (#81677)
This is one of the major changes we (Microsoft) have made in the version
of asan we ship with Visual Studio.

@amyw-msft wrote a blog post outlining this work at
https://devblogs.microsoft.com/cppblog/msvc-address-sanitizer-one-dll-for-all-runtime-configurations/

> With Visual Studio 2022 version 17.7 Preview 3, we have refactored the
MSVC Address Sanitizer (ASan) to depend on one runtime DLL regardless of
the runtime configuration. This simplifies project onboarding and
supports more scenarios, particularly for projects statically linked
(/MT, /MTd) to the C Runtimes. However, static configurations have a new
dependency on the ASan runtime DLL.

> Summary of the changes:

> ASan now works with /MT or /MTd built DLLs when the host EXE was not
compiled with ASan. This includes Windows services, COM components, and
plugins.
Configuring your project with ASan is now simpler, since your project
doesn’t need to uniformly specify the same [runtime
configuration](https://learn.microsoft.com/en-us/cpp/build/reference/md-mt-ld-use-run-time-library?view=msvc-170)
(/MT, /MTd, /MD, /MDd).
ASan workflows and pipelines for /MT or /MTd built projects will need to
ensure the ASan DLL (clang_rt.asan_dynamic-<arch>.dll) is available on
PATH.
The names of the ASan .lib files needed by the linker have changed (the
linker normally takes care of this if not manually specifying lib names
via /INFERASANLIBS)
You cannot mix ASan-compiled binaries from previous versions of the MSVC
Address Sanitizer (this is always true, but especially true in this
case).

Here's the description of these changes from our internal PR

1. Build one DLL that includes everything debug mode needs (not included
here, already contributed upstream).
* Remove #if _DEBUG checks everywhere.
* In some places, this needed to be replaced with a runtime check. In
asan_win.cpp, IsDebugRuntimePresent was added where we are searching for
allocations prior to ASAN initialization.
* In asan_win_runtime_functions.cpp and interception_win.cpp, we need to
be aware of debug runtime DLLs even when not built with _DEBUG.
2. Redirect statically linked functions to the ASAN DLL for /MT
* New exports for each of the C allocation APIs so that the statically
linked portion of the runtime can call them (see asan_malloc_win.cpp,
search MALLOC_DLL_EXPORT). Since we want our stack trace information to
be accurate and without noise, this means we need to capture stack frame
info from the original call and tell it to our DLL export. For this, I
have reused the __asan_win_new_delete_data used for op new/delete
support from asan_win_new_delete_thunk_common.h and moved it into
asan_win_thunk_common.h renamed as __asan_win_stack_data.
* For the C allocation APIs, a new file is included in the
statically-linked /WHOLEARCHIVE lib - asan_malloc_win_thunk.cpp. These
functions simply provide definitions for malloc/free/etc to be used
instead of the UCRT's definitions for /MT and instead call the ASAN DLL
export. /INFERASANLIBS ensures libucrt.lib will not take precedence via
/WHOLEARCHIVE.
* For other APIs, the interception code was called, so a new export is
provided: __sanitizer_override_function.
__sanitizer_override_function_by_addr is also provided to support
__except_handler4 on x86 (due to the security cookie being per-module).
3. Support weak symbols for /MD
* We have customers (CoreCLR) that rely on this behavior and would force
/MT to get it.
* There was sanitizer_win_weak_interception.cpp before, which did some
stuff for setting up the .WEAK section, but this only worked on /MT. Now
stuff registered in the .WEAK section is passed to the ASAN DLL via new
export __sanitizer_register_weak_function (impl in
sanitizer_win_interception.cpp). Unlike linux, multiple weak symbol
registrations are possible here. Current behavior is to give priority on
module load order such that whoever loads last (so priority is given to
the EXE) will have their weak symbol registered.
* Unfortunately, the registration can only occur during the user module
startup, which is after ASAN DLL startup, so any weak symbols used by
ASAN during initialization will not be picked up. This is most notable
for __asan_default_options and friends (see asan_flags.cpp). A mechanism
was made to add a callback for when a certain weak symbol was
registered, so now we process __asan_default_options during module
startup instead of ASAN startup. This is a change in behavior, but
there's no real way around this due to how DLLs are.
4. Build reorganization
* I noticed that our current build configuration is very MSVC-specific
and so did a bit of reworking. Removed a lot of
create_multiple_windows_obj_lib use since it's no longer needed and it
changed how we needed to refer to each object_lib by adding runtime
configuration to the name, conflicting with how it works for non-MSVC.
* No more Win32 static build, use /MD everywhere.
* Building with /Zl to avoid defaultlib warnings.

In addition:
* I've reapplied "[sanitizer][asan][win] Intercept _strdup on Windows
instead of strdup" which broke the previous static asan runtime. That
runtime is gone now and this change is required for the strdup tests to
work.
* I've modified the MSVC clang driver to support linking the correct
asan libraries, including via defining _DLL (which triggers different
defaultlibs and should result in the asan dll thunk being linked, along
with the dll CRT (via defaultlib directives).
* I've made passing -static-libsan an error on windows, and made
-shared-libsan the default. I'm not sure I did this correctly, or in the
best way.
* Modified the test harnesses to add substitutions for the dynamic and
static thunks and to make the library substitutions point to the dynamic
asan runtime for all test configurations on windows. Both the static and
dynamic windows test configurations remain, because they correspond to
the static and dynamic CRT, not the static and dynamic asan runtime
library.

---------

Co-authored-by: Amy Wishnousky <amyw@microsoft.com>
2024-05-29 17:24:45 -07:00
Matheus Izvekov
b86e0992bf
[clang] Enable C++17 relaxed template template argument matching by default (#89807)
This patch will finally allow us to mark C++17 support in clang as
complete.
    
In order to implement this as a DR and avoid breaking reasonable code
that worked before P0522, this patch implements a provisional resolution
for CWG2398: When deducing template template parameters against each other,
and the argument side names a template specialization, instead of just
deducing A, we deduce a synthesized template template parameter based
on A, but with it's parameters using the template specialization's arguments
as defaults.
    
The driver flag is deprecated with a warning.
    
Fixes https://github.com/llvm/llvm-project/issues/36505
2024-05-02 02:02:35 -03:00
Nico Weber
1d7086e475
clang/win: Add a flag to disable default-linking of compiler-rt libraries (#89642)
For ASan, users already manually have to pass in the path to the lib,
and for other libraries they have to pass in the path to the libpath.

With LLVM's unreliable name of the lib (due to
LLVM_ENABLE_PER_TARGET_RUNTIME_DIR confusion and whatnot), it's useful
to be able to opt in to just explicitly passing the paths to the libs
everywhere.

Follow-up of sorts to https://reviews.llvm.org/D65543, and to #87866.
2024-04-23 11:29:59 -04:00
Fangrui Song
5f38436d34
[Driver] -fsanitize=undefined: don't expand to signed-integer-overflow if -fwrapv (#85501)
Linux kernel uses -fwrapv to change signed integer overflows from
undefined behaviors to defined behaviors. However, the security folks
still want -fsanitize=signed-integer-overflow diagnostics. Their
intention can be expressed with -fwrapv
-fsanitize=signed-integer-overflow (#80089). This mode by default
reports recoverable errors while still making signed integer overflows
defined (most UBSan checks are recoverable by default: you get errors in
stderr, but the program is not halted).

-fsanitize=undefined -fwrapv users likely want to suppress
signed-integer-overflow, unless signed-integer-overflow is explicitly
enabled. Implement this suppression.
2024-03-19 10:37:51 -07:00
Kazu Hirata
10886a8f0a [Driver] Use SmallString::operator std::string (NFC) 2024-01-19 22:24:09 -08:00
Fangrui Song
6a0c440159
[Driver,sanitizer] Remove RequiresPIE and msan's NeedPIE setting (#77689)
The two variables cause clang to default to -fPIE when no PIC/PIC option
is
specified.

msan used to require PIE because many `kMemoryLayout` made the low
address (used by ET_EXEC executables) invalid. Current msan.h no longer
does so, rendering this PIE requirement unneeded. The same argument
applies to -fsanitize=dataflow.

On Linux, most builds set CLANG_DEFAULT_PIE_ON_LINUX to 1, making
`RequiresPIE/NeedPIE` redundant on Linux.

(`NeedPIE` is not removed for now due to the -fsanitize-cfi-cross-dso
comment. If it's indeed incompatible with explicit -fno-pic, a warning
is probably better.)
2024-01-11 18:30:16 -08:00
Fangrui Song
c7dce0283b [Driver] Adjust -fsanitize=function & -mexecute-only interop after D158614
clangDriver depends on clangBasic, so clangBasic should not depend on
clangDriver, even just its header. Also remove clangBasic's dependency
on LLVMOption.

The issue can be seen through the bazel commit
d26dd681f9726ed7d43d7c0bdd8ee3cb2db69a2b which is reverted now.

Add hasFlagNoClaim and use it as we don't want to suppress
-Wunused-command-line-argument for -mexecute-only just because
-fsanitize= is specified.
2023-08-30 20:30:13 -07:00
Ying Yi
9ef536a12e [UBSan] Disable the function and kcfi sanitizers on an execute-only target.
An execute-only target disallows data access to code sections.
-fsanitize=function and -fsanitize=kcfi instrument indirect function
calls to load a type hash before the function label. This results in a
non-execute access to the code section and a runtime error.

To solve the issue, -fsanitize=function should not be included in any
check group (e.g. undefined) on an execute-only target. If a user passes
-fsanitize=undefined, there is no error and no warning. However, if the
user explicitly passes -fsanitize=function or -fsanitize=kcfi on an
execute-only target, an error will be emitted.

Fixes: https://github.com/llvm/llvm-project/issues/64931.

Reviewed By: MaskRay, probinson, simon_tatham

Differential Revision: https://reviews.llvm.org/D158614
2023-08-30 17:17:37 +01:00
Blue Gaston
7cabb54f38 [Darwin][StableABI][ASan] Remove version mismatch check from stable abi shim
By its nature the stable abi does not require a version check symbol.
This patch sets -asan-guard-against-version-mismatch=0 for stable abi.
And updates tests to reflect this

rdar://114208627

Differential Revision: https://reviews.llvm.org/D158570
2023-08-24 13:11:54 -07:00
Fangrui Song
a8d3ae7122 [Driver] Default -fsanitize-address-globals-dead-stripping to true for ELF
-fsanitize-address-globals-dead-stripping is the default for non-ELF
platforms. For ELF, we disabled it to work around an ancient gold 2.26
bug. However, some platforms (Fuchsia and PS) default the option to
true.

This patch changes -fsanitize-address-globals-dead-stripping to true for all ELF
platforms. Without specifying -fdata-sections (non-default for most ELF
platforms), `asan_globals` can only be GCed if the monolithic .data/.bss section
is GCed, which makes it less effective.
However, I think this simplified rule is better than making the
-fsanitize-address-globals-dead-stripping default dependent on another option.

Related: D120394
Close https://github.com/llvm/llvm-project/issues/63127

Reviewed By: #sanitizers, eugenis, phosek

Differential Revision: https://reviews.llvm.org/D152604
2023-06-12 17:58:40 -07:00
Sami Tolvanen
5a64a826b9 [Driver] Allow -fsanitize=kcfi with -fsanitize-minimal-runtime
Having both UBSan with the minimal runtime and KCFI enabled can be
useful in low-level software. As there are no conflicts between the
flags, add KCFI to the list of compatible sanitizers.
2023-06-05 20:39:45 +00:00
Roy Sundahl
6f026ff029 Discussion: Darwin Sanitizers Stable ABI
# Darwin Sanitizers Stable ABI

We wish to make it possible to include the AddressSanitizer (ASan) runtime implementation in OSes and for this we need a stable ASan ABI. Based on previous discussions about this topic, our understanding is that freezing the present ABI would impose an excessive burden on other sanitizer developers and for unrelated platforms. Therefore, we propose adding a secondary stable ABI for our use and anyone else in the community seeking the same. We believe that we can define a stable ABI with minimal burden on the community, expecting only to keep existing tests running and implementing stubs when new features are added. We are okay with trading performance for stability with no impact for existing users of ASan while minimizing the maintenance burden for ASan maintainers. We wish to commit this functionality to the LLVM project to maintain it there. This new and stable ABI will abstract away the implementation details allowing new and novel approaches to ASan for developers, researchers and others.

## Details

Rather than adding a lot of conditional code to the LLVM instrumentation phase, which would incur excessive complexity and maintenance cost of adding conditional code into all places that emit a runtime call, we propose a “shim” layer which will map the unstable ABI to the stable ABI:

* A static library (.a library) shim that maps the existing ASan ABI to a generalized, smaller and stable ABI. The library would implement the __asan functions and call into the new ABI. For example:
    * `void __asan_load1(uptr p) { __asan_abi_loadn(p, 1, true); }`
    * `void __asan_load2(uptr p) { __asan_abi_loadn(p, 2, true); }`
    * `void __asan_noabort_load16(uptr p) { __asan_abi_loadn(p, 16, false); }`
    * `void __asan_poison_cxx_array_cookie(uptr p) { __asan_abi_pac(p); }`
* This “shim” library would only be used by people who opt in: A compilation flag in the Clang driver will be used to gate the use of the stable ABI workflow.
* Utilize the existing ability for the ASan instrumentation to prefer runtime calls instead of inlined direct shadow memory accesses.
* Pursue (under the new driver flag) a better separation of abstraction and implementation with:
    * LLVM instrumentation: Calling out for all poisoning, checking and unpoisoning.
    * Runtime: Implementing the stable ABI and being responsible of implementation details of the shadow memory.

## Maintenance

Our aim is that the maintenance burden on the sanitizer developer community be negligible. Stable ABI tests will always pass for non-Darwin platforms. Changes to the existing ABI which would require a change to the shim have been infrequent as the ASan ABI is already relatively stable. Rarely, a change that impacts the contract between LLVM and the shim will occur. Among such foreseeable changes are: 1) changes to a function signature, 2) additions of new functions, or 3) deprecation of an existing function. Following are some examples of reasonable responses to those changes:

* Example: An existing ABI function is changed to return the input parameter on success or NULL on failure. In this scenario, a reasonable change to the shim would be to modify the function signature appropriately and to simply guess at a common-sense implementation.
    * `uptr __asan_load1(uptr p) { __asan_abi_loadn(p, 1, true); return p; }`
* Example: An additional function is added for performance reasons. It has a very similar function signature to other similarly named functions and logically is an extension of that same pattern. In this case it would make sense to apply the same logic as the existing entry points:
    * `void __asan_load128(uptr p) { __asan_abi_loadn(p, 128, true); }`
* Example: An entry point is added to the existing ABI for which there is no obvious stable ABI implementation: In this case, doing nothing in a no-op stub would be acceptable, assuming existing features of ASan can still work without an actual implementation of this new function.
    * `void __asan_prefetch(uptr p) { }`
* Example: An entrypoint in the existing ABI is deprecated and/or deleted:
    * (Delete the entrypoint from the shim.)

We’re looking for buy-in for this level of support.

(Note: Upon acceptance of the general concepts herein, we will add a controlling clang flag, cmake integration, contract for the stable ABI, and the appropriate test infrastructure.)

Reviewed By: eugenis, vitalybuka, MaskRay

Differential Revision: https://reviews.llvm.org/D143675
2023-05-25 08:57:41 -07:00
Fangrui Song
46f366494f -fsanitize=function: use type hashes instead of RTTI objects
Currently we use RTTI objects to check type compatibility. To support non-unique
RTTI objects, commit 5745eccef54ddd3caca278d1d292a88b2281528b added a
`checkTypeInfoEquality` string matching to the runtime.
The scheme is inefficient.

```
_Z1fv:
  .long   846595819                    # jmp
  .long   .L__llvm_rtti_proxy-_Z3funv
  ...

main:
  ...
  # Load the second word (pointer to the RTTI object) and dereference it.
  movslq  4(%rsi), %rax
  movq    (%rax,%rsi), %rdx
  # Is it the desired typeinfo object?
  leaq    _ZTIFvvE(%rip), %rax
  # If not, call __ubsan_handle_function_type_mismatch_v1, which may recover if checkTypeInfoEquality allows
  cmpq    %rax, %rdx
  jne     .LBB1_2
  ...

.section        .data.rel.ro,"aw",@progbits
  .p2align        3, 0x0
.L__llvm_rtti_proxy:
  .quad   _ZTIFvvE
```

Let's replace the indirect `_ZTI` pointer with a type hash similar to
`-fsanitize=kcfi`.

```
_Z1fv:
  .long   3238382334
  .long   2772461324  # type hash

main:
  ...
  # Load the second word (callee type hash) and check whether it is expected
  cmpl    $-1522505972, -4(%rax)
  # If not, fail: call __ubsan_handle_function_type_mismatch
  jne     .LBB2_2
```

The RTTI object derives its name from `clang::MangleContext::mangleCXXRTTI`,
which uses `mangleType`. `mangleTypeName` uses `mangleType` as well. So the
type compatibility change is high-fidelity.

Since we no longer need RTTI pointers in
`__ubsan::__ubsan_handle_function_type_mismatch_v1`, let's switch it back to
version 0, the original signature before
e215996a2932ed7c472f4e94dc4345b30fd0c373 (2019).
`__ubsan::__ubsan_handle_function_type_mismatch_abort` is not
recoverable, so we can revert some changes from
e215996a2932ed7c472f4e94dc4345b30fd0c373.

Reviewed By: samitolvanen

Differential Revision: https://reviews.llvm.org/D148785
2023-05-20 08:24:20 -07:00
Craig Topper
9b1aaaf933 Revert "[RISCV] Move RISCV::RVVBitsPerBlock from TargetParser to Support/RISCVISAInfo.h."
This reverts commit ee9cbe3548cded885c6409d6dd8a616b515a06d3.

I've been told this cauess a namespace clash in lld.
2023-04-29 18:05:56 -07:00
Craig Topper
ee9cbe3548 [RISCV] Move RISCV::RVVBitsPerBlock from TargetParser to Support/RISCVISAInfo.h.
RISCVTargetParser.h has a dependency on a tablegen generated file.

Using RISCVISAInfo.h instead avoids this dependency.

We just need this constant somewhere visible to the frontend and
backend and I'm trying to avoid adding a header just for it.
2023-04-29 15:04:55 -07:00
Fangrui Song
adbdef6a9f [Driver] Make -fsanitize=kcfi,function incompatible
A -fsanitize=kcfi instrumented function has a special instruction/data
before the function entry at a fixed offset.
A -fsanitize=function instrumented function has special instruction/data
after the function entry at a fixed offset (may change to *before* in D148665).

The two instrumentations are not intended to be used together and will become
incompatible after D148665.

Reviewed By: samitolvanen

Differential Revision: https://reviews.llvm.org/D148671
2023-04-19 13:15:33 -07:00
Fangrui Song
e67493f572 [Driver] -fsanitize=kcfi doesn't need RequiresPIE
As mentioned on D148671: this is unneeded. This commit is a no-op for most Linux
builds since CLANG_DEFAULT_PIE_ON_LINUX defaults to 1.
2023-04-19 13:10:46 -07:00
Enna1
b356cd70a2 [hwasan] remove requirment for PIE
The requirement for PIE of hwasan was introduced in https://reviews.llvm.org/D44745,  this patch removes requirement for PIE.

Reviewed By: vitalybuka, MaskRay

Differential Revision: https://reviews.llvm.org/D147121
2023-04-13 14:15:32 +08:00
Paul Kirth
aa1d2693c2 [CodeGen][RISCV] Change Shadow Call Stack Register to X3
ShadowCallStack implementation uses s2 register on RISC-V, but that
choice is problematic for reasons described in:

https://lists.riscv.org/g/sig-toolchains/message/544,
https://github.com/riscv-non-isa/riscv-elf-psabi-doc/issues/370, and
https://github.com/google/android-riscv64/issues/72

The concern over the register choice was also brought up in
https://reviews.llvm.org/D84414.

https://reviews.llvm.org/D84414#2228666 said:

```
  "If the register choice is the only concern about this work, then I think
  we can probably land it as-is and fixup the register choice if we see
  major drawbacks later. Yes, it's an ABI issue, but on the other hand the
  shadow call stack is not a standard ABI anyway.""
```

Since we have now found a sufficient reason to fixup the register
choice, we should go ahead and update the implementation. We propose
using x3(gp) which is now the platform register in the RISC-V ABI.

Reviewed By: asb, hiraditya, mcgrathr, craig.topper

Differential Revision: https://reviews.llvm.org/D146463
2023-04-12 21:06:22 +00:00
Marco Elver
61ed64954b [SanitizerBinaryMetadata] Do not add to GPU code
SanitizerBinaryMetadata should only apply to to host code, and not GPU
code. Recently AMD GPU target code has experimental sanitizer support.

If we're compiling a mixed host/device source file, only add sanitizer
metadata to host code.

Differential Revision: https://reviews.llvm.org/D145519
2023-03-09 10:15:28 +01:00
Sami Tolvanen
a851d46e07 [Clang][Driver] Fix integer normalization with KCFI
Commit 71c7313f42d2b6063fea09854cf4fc46fd0627e1 added integer
normalization for CFI, but doesn't correctly pass the argument
with -fsanitize=kcfi. Set CfiICallNormalizeIntegers also with
SanitizerKind::KCFI to fix the issue.
2023-02-16 00:21:31 +00:00
Marco Elver
421215b919 [SanitizerBinaryMetadata] Support ignore list
For large projects it will be required to opt out entire subdirectories.
In the absence of fine-grained control over the flags passed via the
build system, introduce -fexperimental-sanitize-metadata-ignorelist=.

The format is identical to other sanitizer ignore lists, and its effect
will be to simply not instrument either functions or entire modules
based on the rules in the ignore list file.

Reviewed By: dvyukov

Differential Revision: https://reviews.llvm.org/D143664
2023-02-10 10:25:48 +01:00
Ramon de C Valle
71c7313f42 Add CFI integer types normalization
This commit adds a new option (i.e.,
`-fsanitize-cfi-icall-normalize-integers`) for normalizing integer types
as vendor extended types for cross-language LLVM CFI/KCFI support with
other languages that can't represent and encode C/C++ integer types.

Specifically, integer types are encoded as their defined representations
(e.g., 8-bit signed integer, 16-bit signed integer, 32-bit signed
integer, ...) for compatibility with languages that define
explicitly-sized integer types (e.g., i8, i16, i32, ..., in Rust).

``-fsanitize-cfi-icall-normalize-integers`` is compatible with
``-fsanitize-cfi-icall-generalize-pointers``.

This helps with providing cross-language CFI support with the Rust
compiler and is an alternative solution for the issue described and
alternatives proposed in the RFC
https://github.com/rust-lang/rfcs/pull/3296.

For more information about LLVM CFI/KCFI and cross-language LLVM
CFI/KCFI support for the Rust compiler, see the design document in the
tracking issue https://github.com/rust-lang/rust/issues/89653.

Relands b1e9ab7438a098a18fecda88fc87ef4ccadfcf1e with fixes.

Reviewed By: pcc, samitolvanen

Differential Revision: https://reviews.llvm.org/D139395
2023-02-08 22:24:19 +00:00
Archibald Elliott
8e3d7cf5de [NFC][TargetParser] Remove llvm/Support/TargetParser.h 2023-02-07 11:08:21 +00:00
Roland McGrath
03ff435da5 [RISCV] Default to -ffixed-x18 for Fuchsia
Fuchsia's ABI always reserves the x18 (s2) register for the
ShadowCallStack ABI, even when -fsanitize=shadow-call-stack is
not enabled.

Reviewed By: phosek

Differential Revision: https://reviews.llvm.org/D143355
2023-02-05 18:51:18 -08:00
Archibald Elliott
8c712296fb [NFC][TargetParser] Remove llvm/Support/AArch64TargetParser.h
Removes the forwarding header `llvm/Support/AArch64TargetParser.h`.

I am proposing to do this for all the forwarding headers left after
rGf09cf34d00625e57dea5317a3ac0412c07292148 - for each header:
- Update all relevant in-tree includes
- Remove the forwarding Header

Differential Revision: https://reviews.llvm.org/D140999
2023-02-03 17:34:01 +00:00
Mitch Phillips
b88ebb3d94 Revert "Add CFI integer types normalization"
This reverts commit b1e9ab7438a098a18fecda88fc87ef4ccadfcf1e.

Reason: Looks like it broke the MSan buildbot, more details in the
phabricator review: https://reviews.llvm.org/D139395
2023-02-02 15:48:50 -08:00
Ramon de C Valle
b1e9ab7438 Add CFI integer types normalization
This commit adds a new option (i.e.,
`-fsanitize-cfi-icall-normalize-integers`) for normalizing integer types
as vendor extended types for cross-language LLVM CFI/KCFI support with
other languages that can't represent and encode C/C++ integer types.

Specifically, integer types are encoded as their defined representations
(e.g., 8-bit signed integer, 16-bit signed integer, 32-bit signed
integer, ...) for compatibility with languages that define
explicitly-sized integer types (e.g., i8, i16, i32, ..., in Rust).

``-fsanitize-cfi-icall-normalize-integers`` is compatible with
``-fsanitize-cfi-icall-generalize-pointers``.

This helps with providing cross-language CFI support with the Rust
compiler and is an alternative solution for the issue described and
alternatives proposed in the RFC
https://github.com/rust-lang/rfcs/pull/3296.

For more information about LLVM CFI/KCFI and cross-language LLVM
CFI/KCFI support for the Rust compiler, see the design document in the
tracking issue https://github.com/rust-lang/rust/issues/89653.

Reviewed By: pcc, samitolvanen

Differential Revision: https://reviews.llvm.org/D139395
2023-02-01 17:48:03 +00:00
Fangrui Song
1ff3064c65 [Driver] Simplify -fsanitize-memory-track-origins handling. NFC 2023-01-05 22:21:13 -08:00
Dmitry Vyukov
dbe8c2c316 Use-after-return sanitizer binary metadata
Currently per-function metadata consists of:
(start-pc, size, features)

This adds a new UAR feature and if it's set an additional element:
(start-pc, size, features, stack-args-size)

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D136078
2022-12-05 14:40:31 +01:00
Marco Elver
b95646fe70 Revert "Use-after-return sanitizer binary metadata"
This reverts commit d3c851d3fc8b69dda70bf5f999c5b39dc314dd73.

Some bots broke:

- https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/clang-linux-x64/b8796062278266465473/overview
- https://lab.llvm.org/buildbot/#/builders/124/builds/5759/steps/7/logs/stdio
2022-11-30 23:35:50 +01:00
Dmitry Vyukov
d3c851d3fc Use-after-return sanitizer binary metadata
Currently per-function metadata consists of:
(start-pc, size, features)

This adds a new UAR feature and if it's set an additional element:
(start-pc, size, features, stack-args-size)

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D136078
2022-11-30 14:50:22 +01:00
Dmitry Vyukov
0aedf9d714 Revert "Use-after-return sanitizer binary metadata"
This reverts commit e6aea4a5db09c845276ece92737a6aac97794100.

Broke tests:
https://lab.llvm.org/buildbot/#/builders/16/builds/38992
2022-11-30 09:38:56 +01:00
Dmitry Vyukov
e6aea4a5db Use-after-return sanitizer binary metadata
Currently per-function metadata consists of:
(start-pc, size, features)

This adds a new UAR feature and if it's set an additional element:
(start-pc, size, features, stack-args-size)

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D136078
2022-11-30 09:14:19 +01:00
Kazu Hirata
dbb1130966 Revert "Use-after-return sanitizer binary metadata"
This reverts commit a1255dc467f7ce57a966efa76bbbb4ee91d9115a.

This patch results in:

  llvm/lib/CodeGen/SanitizerBinaryMetadata.cpp:57:17: error: no member
  named 'size' in 'llvm::MDTuple'
2022-11-29 09:04:00 -08:00
Dmitry Vyukov
a1255dc467 Use-after-return sanitizer binary metadata
Currently per-function metadata consists of:
(start-pc, size, features)

This adds a new UAR feature and if it's set an additional element:
(start-pc, size, features, stack-args-size)

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D136078
2022-11-29 17:37:36 +01:00
Sami Tolvanen
5a3d6ce956 [Clang][Driver] Add KCFI to SupportsCoverage
Allow `-fsanitize=kcfi` to be enabled with `-fsanitize-coverage=` modes
such as `trace-{pc,cmp}`.

Link: https://github.com/ClangBuiltLinux/linux/issues/1743

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D138458
2022-11-22 18:20:04 +00:00