From: Paulo Alcantara <pc@manguebit.org>
To: Frank Sorenson <sorenson@redhat.com>, linux-cifs@vger.kernel.org
Cc: linkinjeon@kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] cifs: fix loff_t underflow in cifs_remap_file_range() when len == 0
Date: Mon, 24 Aug 2026 09:56:09 -0300 [thread overview]
Message-ID: <a7e552d6083f042e9b5e8cd0b0e93cf8@manguebit.org> (raw)
In-Reply-To: <20260822215517.2353835-1-sorenson@redhat.com>
Frank Sorenson <sorenson@redhat.com> writes:
> With len == 0 (clone to EOF), the effective length is computed as:
>
> len = src_inode->i_size - off;
>
> If off > i_size, this is a negative loff_t, corrupting the ByteCount
> in the FSCTL_DUPLICATE_EXTENTS_TO_FILE request and inverting the range
> in filemap_write_and_wait_range(). The existing off >= i_size check
> fires only after the ioctl has already been sent.
>
> Snapshot i_size_read() once for both the bounds check and the length
> calculation, eliminating the TOCTOU and 32-bit torn-read risk. Reject
> off > src_size with -EINVAL. Treat off == src_size as a no-op,
> consistent with __generic_remap_file_range_prep().
> ...
Applied.
prev parent reply other threads:[~2026-08-24 12:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-22 21:55 [PATCH] cifs: fix loff_t underflow in cifs_remap_file_range() when len == 0 Frank Sorenson
2026-08-23 1:14 ` Namjae Jeon
2026-08-24 12:56 ` Paulo Alcantara [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=a7e552d6083f042e9b5e8cd0b0e93cf8@manguebit.org \
--to=pc@manguebit.org \
--cc=linkinjeon@kernel.org \
--cc=linux-cifs@vger.kernel.org \
--cc=sorenson@redhat.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox