strncpy() has been a persistent source of bugs due to its ambiguous
intended usage and frequently counter-intuitive semantics: it may not
NUL-terminate the destination, and it unconditionally zero-pads to the
full length, which isn't always needed. All former callers have been
migrated[1] to:
- strscpy() for NUL-terminated destinations
- strscpy_pad() for NUL-terminated destinations needing zero-padding
- strtomem_pad() for non-NUL-terminated fixed-width fields
- memcpy_and_pad() for bounded copies with explicit padding
- memcpy() for known-length copies
Remove the generic implementation, its declaration, the FORTIFY_SOURCE
wrapper, and associated tests.
Link: https://github.com/KSPP/linux/issues/90 [1]
Signed-off-by: Kees Cook <kees@kernel.org>
It seems the Clang can see through OPTIMIZER_HIDE_VAR when the constant
is coming from sizeof. Adding "volatile" back to these variables solves
this false positive without reintroducing the issues that originally led
to switching to OPTIMIZER_HIDE_VAR in the first place[1].
Reported-by: Nathan Chancellor <nathan@kernel.org>
Closes: https://github.com/ClangBuiltLinux/linux/issues/2075 [1]
Cc: Jannik Glückert <jannik.glueckert@gmail.com>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Fixes: 6ee149f61b ("kunit/fortify: Replace "volatile" with OPTIMIZER_HIDE_VAR()")
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250628234034.work.800-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
