CVE-2024-44963 btrfs: do not BUG_ON() when freeing tree block after error

2024-09-0418:36:00

Linux

www.cve.org

linux kernel

btrfs

vulnerability

EPSS

Percentile

9.6%

JSON

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

btrfs: do not BUG_ON() when freeing tree block after error

When freeing a tree block, at btrfs_free_tree_block(), if we fail to
create a delayed reference we don’t deal with the error and just do a
BUG_ON(). The error most likely to happen is -ENOMEM, and we have a
comment mentioning that only -ENOMEM can happen, but that is not true,
because in case qgroups are enabled any error returned from
btrfs_qgroup_trace_extent_post() (can be -EUCLEAN or anything returned
from btrfs_search_slot() for example) can be propagated back to
btrfs_free_tree_block().

So stop doing a BUG_ON() and return the error to the callers and make
them abort the transaction to prevent leaking space. Syzbot was
triggering this, likely due to memory allocation failure injection.

CNA Affected

[
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "unaffected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/btrfs/ctree.c",
      "fs/btrfs/extent-tree.c",
      "fs/btrfs/extent-tree.h",
      "fs/btrfs/free-space-tree.c",
      "fs/btrfs/ioctl.c",
      "fs/btrfs/qgroup.c"
    ],
    "versions": [
      {
        "version": "1da177e4c3f4",
        "lessThan": "98251cd60b4d",
        "status": "affected",
        "versionType": "git"
      },
      {
        "version": "1da177e4c3f4",
        "lessThan": "bb3868033a4c",
        "status": "affected",
        "versionType": "git"
      }
    ]
  },
  {
    "product": "Linux",
    "vendor": "Linux",
    "defaultStatus": "affected",
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "programFiles": [
      "fs/btrfs/ctree.c",
      "fs/btrfs/extent-tree.c",
      "fs/btrfs/extent-tree.h",
      "fs/btrfs/free-space-tree.c",
      "fs/btrfs/ioctl.c",
      "fs/btrfs/qgroup.c"
    ],
    "versions": [
      {
        "version": "6.10.5",
        "lessThanOrEqual": "6.10.*",
        "status": "unaffected",
        "versionType": "custom"
      },
      {
        "version": "6.11",
        "lessThanOrEqual": "*",
        "status": "unaffected",
        "versionType": "original_commit_for_fix"
      }
    ]
  }
]