j-montgomery/freestanding_sanitizers

Freestanding sanitizers that can be used anywhere

freestanding_sanitizers's Issues

Implement missing UBSAN handler APIs

The following UBSAN APIs are either misnamed or missing from the current implementation:

• Handle add_overflow
• Handle cfi_bad_type
• Handle cfi_check_fail
• Handle dynamic type cache miss
• Handle float cast overflow v1 and v2
• Handle function type mismatch v1

Implement missing UBSAN user interface functions

The following interface functions are missing from the current implementation. As user-code may implement these, they're part of the public API libfreesan has to implement as well.

• __ubsan_on_report
• __ubsan_default_options
• __ubsan_get_current_report_data

Expand the test suite to cover all APIs

It'd be best if we could somehow port the ubsan tests already used by compiler-rt. Alternatively, continue with the current system of manually written tests.

Document the various macro interfaces that control libfreesan build options

As an example, -DSANITIZER_CONFIG_BACKTRACE_ENABLE=0 may be set to disable backtrace usage on linux systems.

Update the README to reflect UBSAN API status

The README was not updated before merging #3. Oops.

Provide documentation (with examples) on how to integrate libfreesan

There is no written documentation on how say, an embedded developer might integrate libfreesan into their bare metal system and make use of it.

Support compilation under -Werror=switch-default

switch statements in the ubsan handlers do not implement default case statements in places where we're relying on the compiler to provide us with one of a finite number of object types. However, the compiler isn't smart enough to realize that it's enforcing its own rules and can throw an error if the library is built with overly strict settings. libfreesan should provide a default case statement to deal with those cases gracefully.

Add __ubsan_handle_type_mismatch handler

Older versions of Clang and somewhat newer GCCs (e.g. <= v9.x) implement type mismatch as
__ubsan_handle_type_mismatch() instead of the corresponding *_v1 APIs. To improve backwards compatibility, libfreesan should support the older APIs:

• __ubsan_handle_type_mismatch()
• __ubsan_handle_nonnull_return()
• __ubsan_handle_nullability_return()
• __ubsan_handle_function_type_mismatch()

Provide optional bare metal stubs for standard library functions if they don't exist on targets

The primary use case for libfreesan is targets that do not have support for the sanitizer library that normally ships with the compiler. Many of these targets also lack access to correctly implemented standard libraries. Basic (albeit slow) implementations should be optionally provided to help integrate libfreesan in these difficult environments.