On Mon, Mar 30, 2026 at 02:20:02PM +0100, [email protected] wrote:
> From: David Laight <[email protected]>
>
> If the string is constant there is no need to call __real_strlen()
> even when maxlen is a variable - just return the smaller value.
>
> If the size of the string variable is unknown fortify_panic() can't be
> called, change the condition so that the compiler can optimise it away.
>
> Change __compiletime_strlen(p) to return a 'non-constant' value
> for non-constant strings (the same as __builtin_strlen()).
> Simplify since it is only necessary to check that the size is constant
> and that the last character is '\0'.
> Explain why it is different from __builtin_strlen().
> Update the kunit tests to match.
See also
commit d07c0acb4f41 ("fortify: Fix __compiletime_strlen() under
UBSAN_BOUNDS_LOCAL")
-Kees
--
Kees Cook
