Add minimal kernel runtime for UBSAN

[guest-svmhdvn]

Summary

To use:

1. Add options UBSAN to the kernel configuration file
2. Add WITH_UBSAN=yes to src.conf(5) to enable UBSAN
3. (optional) Add WITH_UBSAN_SANITIZE_ALL=yes to src.conf(5) to check all kernel source files for undefined behaviour

To check individual kernel source files with UBSAN, add compile-with "${NORMAL_C} ${ENABLE_UBSAN}" to the corresponding line in sys/conf/files. To disable UBSAN for individual files (even with WITH_UBSAN_SANITIZE_ALL=yes), add compile-with "${NORMAL_C} ${DISABLE_UBSAN}" to the corresponding line in sys/conf/files.

[guest-svmhdvn]

Add license after consulting with Ed

[emaste]

share/man/man5/src.conf.5

1512–1515

src.conf.5 is generated automatically, via tools/build/options/makeman. You need to create WITH_ files in that directory.

sys/conf/NOTES

3034–3036

This should go up near INVARIANTS INVARIANT_SUPPORT DIAGNOSTIC etc., with a slightly longer description.

sys/conf/options

1002

also near INVARIANTS and other debugging options
Also something like # undefined behaviour sanitizer (ubsan) runtime - to highlight that it's only one part of the ubsan mechanism

sys/libkern/ubsan.c

349

probably need an assert that data->type_check_kind <= nitems(type_check_kinds)

[guest-svmhdvn]

• Moved around kernel options to correct locations and added additional comments
• Added assert for checking bounds of array access

[op]

sys/libkern/ubsan.c

112

FreeBSD style(9) requires parentheses after the return, like return (1 << (type->type_info >> 1)); and new line after { when there are no local variables.

[guest-svmhdvn]

Fixed style(9) issues.

[guest-svmhdvn]

Wrong commit order, accidentally deleted license.

[emaste]

NetBSD kernel ubsan imported in 0645126fae62300fe587199cf8eade00842cb9c1