Messages in this thread | | | Date | Thu, 18 Sep 2008 08:57:19 +0800 | From | "Eugene Teo" <> | Subject | Re: [PATCH 4/4] ext3: Avoid printk floods in the face of directory corruption |
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On Sat, Sep 13, 2008 at 11:32 PM, Theodore Ts'o <tytso@mit.edu> wrote: > Note: some people thinks this represents a security bug, since it > might make the system go away while it is printing a large number of > console messages, especially if a serial console is involved. Hence, > it has been assigned CVE-2008-3528, but it requires that the attacker > either has physical access to your machine to insert a USB disk with a > corrupted filesystem image (at which point why not just hit the power > button), or is otherwise able to convince the system administrator to > mount an arbitrary filesystem image (at which point why not just > include a setuid shell or world-writable hard disk device file or some > such). Me, I think they're just being silly.
The description should explain what the problem is. And the last sentence is a little ambiguous.
This is a user-triggerable DoS. The administrator who mounted the filesystem image or partition might not know that the dir->i_size and dir->i_blocks are corrupted. A remote user just need to perform either a read or write operation to the mounted image or partition, and this could trigger the problem, resulting in a denial of service.
Take note that another problem the test image shows is that, the ext2/3 (and possibly ext4) filesystem does not honour the read-only mode when the revision level is too high. That is, when le32_to_cpu(es->s_rev_level) > EXT3_MAX_SUPP_REV. Eric replied me in a private email that this is a different, and unrelated bug that will be fixed.
Thanks, Eugene
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