Re: [PATCH] fscrypt: Fix uninit-value in ovl_fill_real

[Qing Wang]

On Sun, 25 Jan 2026 at 02:25, Eric Biggers wrote:
> For KMSAN issues, it's important to root-cause them.
> Zero-initialization isn't necessarily the right fix.
> 
> In this case, it looks like ovl_fill_real() is incorrectly assuming that
> the name is NUL-terminated.
> 
> Yet, the name passed to dir_context::actor isn't normally
> NUL-terminated.  Even for a regular directory, ext4 just passes a
> pointer to the filename in the ext4_dir_entry_2 in the buffer cache.
> 
> The encrypted directory case doesn't seem to be fundamentally different.
> Just KMSAN is able to report the issue because the memory is in a slab
> buffer rather than the buffer cache.
> 
> Can you consider fixing ovl_fill_real()?  Instead of strcmp(".."), it
> should check whether namelen is 2 and the first two chars are '.'.

Hi Eric,
Thanks for your reply. I agreed with your idea and resend a new patch.

https://lore.kernel.org/all/20260126062216.496560-1-wangqing7171@xxxxxxxxx/

Looking forward to your next review.

-- 
Best Regards,
Qing