CVE-2022-50379

Summary

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

btrfs: fix race between quota enable and quota rescan ioctl

When enabling quotas, at btrfs_quota_enable(), after committing the transaction, we change fs_info->quota_root to point to the quota root we created and set BTRFS_FS_QUOTA_ENABLED at fs_info->flags. Then we try to start the qgroup rescan worker, first by initializing it with a call to qgroup_rescan_init() - however if that fails we end up freeing the quota root but we leave fs_info->quota_root still pointing to it, this can later result in a use-after-free somewhere else.

We have previously set the flags BTRFS_FS_QUOTA_ENABLED and BTRFS_QGROUP_STATUS_FLAG_ON, so we can only fail with -EINPROGRESS at btrfs_quota_enable(), which is possible if someone already called the quota rescan ioctl, and therefore started the rescan worker.

So fix this by ignoring an -EINPROGRESS and asserting we can't get any other error.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux5d23515be66904fa3b1b5d6bd72d2199cd2447ab < c97f6d528c3f1c83a6b792a8a7928c236c80b8feaffected
LinuxLinux5d23515be66904fa3b1b5d6bd72d2199cd2447ab < 26b7c0ac49a3eea15559c9d84863736a6d1164b4affected
LinuxLinux5d23515be66904fa3b1b5d6bd72d2199cd2447ab < 47b5ffe86332af95f0f52be0a63d4da7c2b37b55affected
LinuxLinux5d23515be66904fa3b1b5d6bd72d2199cd2447ab < 4b996a3014ef014af8f97b60c35f5289210a4720affected
LinuxLinux5d23515be66904fa3b1b5d6bd72d2199cd2447ab < 0efd9dfc00d677a1d0929319a6103cb2dfc41c22affected
LinuxLinux5d23515be66904fa3b1b5d6bd72d2199cd2447ab < 6c22f86dd221eba0c7af645b1af73dcbc04ee27baffected
LinuxLinux5d23515be66904fa3b1b5d6bd72d2199cd2447ab < 331cd9461412e103d07595a10289de90004ac890affected
LinuxLinux4.17affected
LinuxLinux0 < 4.17unaffected
LinuxLinux4.19.262 <= 4.19.*unaffected
LinuxLinux5.4.220 <= 5.4.*unaffected
LinuxLinux5.10.150 <= 5.10.*unaffected
LinuxLinux5.15.75 <= 5.15.*unaffected
LinuxLinux5.19.17 <= 5.19.*unaffected
LinuxLinux6.0.3 <= 6.0.*unaffected
LinuxLinux6.1 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

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

References