CVE-2021-47458: ocfs2: mount fails with buffer overflow in strlen

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-22 · updated 2026-08-04
Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: ocfs2: mount fails with buffer overflow in strlen Starting with kernel 5.11 built with CONFIG_FORTIFY_SOURCE mouting an ocfs2 filesystem with either o2cb or pcmk cluster stack fails with the trace below. Problem seems to be that strings for cluster stack and cluster name are not guaranteed to be null terminated in the disk representation, while strlcpy assumes that the source string is always null terminated. This causes a read outside of the source string triggering the buffer overflow detection. detected buffer overflow in strlen ------------[ cut here ]------------ kernel BUG at lib/string.c:1149! invalid opcode: 0000 [#1] SMP PTI CPU: 1 PID: 910 Comm: mount.ocfs2 Not tainted 5.14.0-1-amd64 #1 Debian 5.14.6-2 RIP: 0010:fortify_panic+0xf/0x11 ... Call Trace: ocfs2_initialize_super.isra.0.cold+0xc/0x18 [ocfs2] ocfs2_fill_super+0x359/0x19b0 [ocfs2] mount_bdev+0x185/0x1b0 legacy_get_tree+0x27/0x40 vfs_get_tree+0x25/0xb0 path_mount+0x454/0xa20 __x64_sys_mount+0x103/0x140 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae

Affected products

Linux kernel: before 4.4.290; from 4.5 before 4.9.288; from 4.10 before 4.14.253; from 4.15 before 4.19.214; from 4.20 before 5.4.156; from 5.5 before 5.10.76 — fixed in 4.14.253, 4.19.214, 4.4.290, 4.9.288, 5.10.76, 5.14.15

How to fix

Upgrade to a fixed version: Linux kernel 4.14.253, 4.19.214, 4.4.290, 4.9.288. Check the vendor advisory for mitigations.

References

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