Description
In the Linux kernel, the following vulnerability has been resolved:
ext4: make sure the first directory block is not a hole
The syzbot constructs a directory that has no dirblock but is non-inline, i.e. the first directory block is a hole. And no errors are reported when creating files in this directory in the following flow.
ext4_mknod ... ext4_add_entry // Read block 0 ext4_read_dirblock(dir, block, DIRENT) bh = ext4_bread(NULL, inode, block, 0) if (!bh && (type == INDEX || type == DIRENT_HTREE)) // The first directory block is a hole // But type == DIRENT, so no error is reported.
After that, we get a directory block without '.' and '..' but with a valid dentry. This may cause some code that relies on dot or dotdot (such as make_indexed_dir()) to crash.
Therefore when ext4_read_dirblock() finds that the first directory block is a hole report that the filesystem is corrupted and return an error to avoid loading corrupted data from disk causing something bad.
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HAffected software
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux | >= 3a17ca864baffc0c6f6e8aad525aa4365775a193, < d81d7e347d1f1f48a5634607d39eb90c161c8afe; >= 4e19d6b65fb4fc42e352ce9883649e049da14743, < e02f9941e8c011aa3eafa799def6a134ce06bcfa; >= 4e19d6b65fb4fc42e352ce9883649e049da14743, < de2a011a13a46468a6e8259db58b1b62071fe136; >= 4e19d6b65fb4fc42e352ce9883649e049da14743, < 9771e3d8365ae1dd5e8846a204cb9af14e3e656a; >= 4e19d6b65fb4fc42e352ce9883649e049da14743, < b609753cbbd38f8c0affd4956c0af178348523ac; >= 4e19d6b65fb4fc42e352ce9883649e049da14743, < c3893d9de8ee153baac56d127d844103488133b5; >= 4e19d6b65fb4fc42e352ce9883649e049da14743, < 299bc6ffa57e04e74c6cce866d6c0741fb4897a1; >= 4e19d6b65fb4fc42e352ce9883649e049da14743, < f9ca51596bbfd0f9c386dd1c613c394c78d9e5e6; 3f0307b0d2d8b333a6964fc4c820dc86896fd1cf; 514631c2225c1fd556c799cc1893fb27b0f48f00; 7f1f86276515f6816a98f6ca3ef99c827d54642f; 5021b7a5bdd6bb859eb648c3da71cdd6aae1d133; >= 4.19.62, < 4.19.320; >= 4.9.187, < 4.10; >= 4.14.135, < 4.15; >= 5.1.21, < 5.2; >= 5.2.4, < 5.3 |
| Linux | Linux | 5.3 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | < V1.1.1 |
References
- https://git.kernel.org/stable/c/299bc6ffa57e04e74c6cce866d6c0741fb4897a1Patch
- https://git.kernel.org/stable/c/9771e3d8365ae1dd5e8846a204cb9af14e3e656aPatch
- https://git.kernel.org/stable/c/b609753cbbd38f8c0affd4956c0af178348523acPatch
- https://git.kernel.org/stable/c/c3893d9de8ee153baac56d127d844103488133b5Patch
- https://git.kernel.org/stable/c/d81d7e347d1f1f48a5634607d39eb90c161c8afePatch
- https://git.kernel.org/stable/c/de2a011a13a46468a6e8259db58b1b62071fe136Patch
- https://git.kernel.org/stable/c/e02f9941e8c011aa3eafa799def6a134ce06bcfaPatch
- https://git.kernel.org/stable/c/f9ca51596bbfd0f9c386dd1c613c394c78d9e5e6Patch
- https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
- https://cert-portal.siemens.com/productcert/html/ssa-265688.html
Timeline
- Published
- Aug 17, 2024
- Last modified
- Oct 15, 2026
- NVD status
- Modified