CVE-2021-47579

Summary

In the Linux kernel, the following vulnerability has been resolved:

ovl: fix warning in ovl_create_real()

Syzbot triggered the following warning in ovl_workdir_create() -> ovl_create_real():

if (!err && WARN_ON(!newdentry->d_inode)) {

The reason is that the cgroup2 filesystem returns from mkdir without instantiating the new dentry.

Weird filesystems such as this will be rejected by overlayfs at a later stage during setup, but to prevent such a warning, call ovl_mkdir_real() directly from ovl_workdir_create() and reject this case early.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxe9be9d5e76e34872f0c37d72e25bc27fe9e2c54c < 445d2dc63e5871d218f21b8f62ab29ac72f2e6b8affected
LinuxLinuxe9be9d5e76e34872f0c37d72e25bc27fe9e2c54c < f9f300a92297be8250547347fd52216ef0177ae0affected
LinuxLinuxe9be9d5e76e34872f0c37d72e25bc27fe9e2c54c < 6859985a2fbda5d1586bf44538853e1be69e85f7affected
LinuxLinuxe9be9d5e76e34872f0c37d72e25bc27fe9e2c54c < d2ccdd4e4efab06178608a34d7bfb20a54104c02affected
LinuxLinuxe9be9d5e76e34872f0c37d72e25bc27fe9e2c54c < 1f5573cfe7a7056e80a92c7a037a3e69f3a13d1caffected
LinuxLinux3.18affected
LinuxLinux0 < 3.18unaffected
LinuxLinux4.19.222 <= 4.19.*unaffected
LinuxLinux5.4.168 <= 5.4.*unaffected
LinuxLinux5.10.88 <= 5.10.*unaffected
LinuxLinux5.15.11 <= 5.15.*unaffected
LinuxLinux5.16 <= *unaffected

Weaknesses

ADP Enrichment

CVE Program Container

Additional References

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

References