linux-kernel - Re: [PATCH v2] ext4: fix OOB read when checking dotdot dir

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Message-ID: <174261457018.1344301.17270350351088330714.b4-ty@mit.edu>
Date: Fri, 21 Mar 2025 23:36:14 -0400
From: "Theodore Ts'o" <tytso@....edu>
To: linux-kernel@...r.kernel.org, linux-ext4@...r.kernel.org,
        "Acs, Jakub" <acsjakub@...zon.de>
Cc: "Theodore Ts'o" <tytso@....edu>, acsjakub@...zon.com,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        Mahmoud Adam <mngyadam@...zon.com>, stable@...r.kernel.org,
        security@...nel.org
Subject: Re: [PATCH v2] ext4: fix OOB read when checking dotdot dir


On Thu, 20 Mar 2025 15:46:49 +0000, Acs, Jakub wrote:
> Mounting a corrupted filesystem with directory which contains '.' dir
> entry with rec_len == block size results in out-of-bounds read (later
> on, when the corrupted directory is removed).
> 
> ext4_empty_dir() assumes every ext4 directory contains at least '.'
> and '..' as directory entries in the first data block. It first loads
> the '.' dir entry, performs sanity checks by calling ext4_check_dir_entry()
> and then uses its rec_len member to compute the location of '..' dir
> entry (in ext4_next_entry). It assumes the '..' dir entry fits into the
> same data block.
> 
> [...]

Applied, thanks!

[1/1] ext4: fix OOB read when checking dotdot dir
      commit: d5e206778e96e8667d3bde695ad372c296dc9353

Best regards,
-- 
Theodore Ts'o <tytso@....edu>