From: Qing Wang <wangqing7171@gmail.com>
To: ebiggers@kernel.org
Cc: jaegeuk@kernel.org, linux-fscrypt@vger.kernel.org,
linux-kernel@vger.kernel.org,
syzbot+d130f98b2c265fae5297@syzkaller.appspotmail.com,
tytso@mit.edu, wangqing7171@gmail.com
Subject: Re: [PATCH] fscrypt: Fix uninit-value in ovl_fill_real
Date: Mon, 26 Jan 2026 14:33:55 +0800 [thread overview]
Message-ID: <20260126063355.504157-1-wangqing7171@gmail.com> (raw)
In-Reply-To: <20260124182547.GA2762@quark>
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@gmail.com/
Looking forward to your next review.
--
Best Regards,
Qing
prev parent reply other threads:[~2026-01-26 6:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-23 7:30 [PATCH] fscrypt: Fix uninit-value in ovl_fill_real Qing Wang
2026-01-24 18:25 ` Eric Biggers
2026-01-26 6:22 ` [PATCH v2] " Qing Wang
2026-01-27 3:47 ` Eric Biggers
2026-01-27 6:10 ` [PATCH] " Qing Wang
2026-01-26 6:33 ` Qing Wang [this message]
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