CVE-2024-26956

NameCVE-2024-26956
DescriptionIn the Linux kernel, the following vulnerability has been resolved: nilfs2: fix failure to detect DAT corruption in btree and direct mappings Patch series "nilfs2: fix kernel bug at submit_bh_wbc()". This resolves a kernel BUG reported by syzbot. Since there are two flaws involved, I've made each one a separate patch. The first patch alone resolves the syzbot-reported bug, but I think both fixes should be sent to stable, so I've tagged them as such. This patch (of 2): Syzbot has reported a kernel bug in submit_bh_wbc() when writing file data to a nilfs2 file system whose metadata is corrupted. There are two flaws involved in this issue. The first flaw is that when nilfs_get_block() locates a data block using btree or direct mapping, if the disk address translation routine nilfs_dat_translate() fails with internal code -ENOENT due to DAT metadata corruption, it can be passed back to nilfs_get_block(). This causes nilfs_get_block() to misidentify an existing block as non-existent, causing both data block lookup and insertion to fail inconsistently. The second flaw is that nilfs_get_block() returns a successful status in this inconsistent state. This causes the caller __block_write_begin_int() or others to request a read even though the buffer is not mapped, resulting in a BUG_ON check for the BH_Mapped flag in submit_bh_wbc() failing. This fixes the first issue by changing the return value to code -EINVAL when a conversion using DAT fails with code -ENOENT, avoiding the conflicting condition that leads to the kernel bug described above. Here, code -EINVAL indicates that metadata corruption was detected during the block lookup, which will be properly handled as a file system error and converted to -EIO when passing through the nilfs2 bmap layer.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
ReferencesDLA-3840-1, DLA-3842-1, DSA-5681-1, ELA-1093-1, ELA-1116-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)jessie, jessie (lts)3.16.84-1vulnerable
stretch (security)4.9.320-2vulnerable
stretch (lts), stretch4.9.320-3vulnerable
buster (security), buster, buster (lts)4.19.316-1fixed
bullseye5.10.223-1fixed
bullseye (security)5.10.226-1fixed
bookworm6.1.115-1fixed
bookworm (security)6.1.112-1fixed
trixie6.11.7-1fixed
sid6.11.9-1fixed
linux-4.19 (PTS)jessie, jessie (lts)4.19.316-1~deb8u1fixed
stretch (security)4.19.232-1~deb9u1vulnerable
stretch (lts), stretch4.19.316-1~deb9u1fixed
linux-5.10 (PTS)jessie, jessie (lts)5.10.226-1~deb8u1fixed
stretch (lts), stretch5.10.226-1~deb9u1fixed
buster, buster (lts)5.10.226-1~deb10u1fixed
buster (security)5.10.218-1~deb10u1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcejessie(unfixed)end-of-life
linuxsourcestretch(unfixed)end-of-life
linuxsourcebuster4.19.316-1DLA-3840-1
linuxsourcebullseye5.10.216-1DSA-5681-1
linuxsourcebookworm6.1.85-1
linuxsource(unstable)6.7.12-1
linux-4.19sourcejessie4.19.316-1~deb8u1ELA-1116-1
linux-4.19sourcestretch4.19.316-1~deb9u1ELA-1116-1
linux-5.10sourcejessie5.10.216-1~deb8u1ELA-1093-1
linux-5.10sourcestretch5.10.216-1~deb9u1ELA-1093-1
linux-5.10sourcebuster5.10.216-1~deb10u1DLA-3842-1

Notes

https://git.kernel.org/linus/f2f26b4a84a0ef41791bd2d70861c8eac748f4ba (6.9-rc1)

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