Use of Uninitialized Resource Affecting kernel-devel package, versions *


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating

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  • Snyk ID SNYK-RHEL7-KERNELDEVEL-8417128
  • published 26 Nov 2024
  • disclosed 19 Nov 2024

How to fix?

There is no fixed version for RHEL:7 kernel-devel.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-devel package and not the kernel-devel package as distributed by RHEL. See How to fix? for RHEL:7 relevant fixed versions and status.

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

btrfs: reinitialize delayed ref list after deleting it from the list

At insert_delayed_ref() if we need to update the action of an existing ref to BTRFS_DROP_DELAYED_REF, we delete the ref from its ref head's ref_add_list using list_del(), which leaves the ref's add_list member not reinitialized, as list_del() sets the next and prev members of the list to LIST_POISON1 and LIST_POISON2, respectively.

If later we end up calling drop_delayed_ref() against the ref, which can happen during merging or when destroying delayed refs due to a transaction abort, we can trigger a crash since at drop_delayed_ref() we call list_empty() against the ref's add_list, which returns false since the list was not reinitialized after the list_del() and as a consequence we call list_del() again at drop_delayed_ref(). This results in an invalid list access since the next and prev members are set to poison pointers, resulting in a splat if CONFIG_LIST_HARDENED and CONFIG_DEBUG_LIST are set or invalid poison pointer dereferences otherwise.

So fix this by deleting from the list with list_del_init() instead.

CVSS Scores

version 3.1
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NVD

5.5 medium
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    None
  • Integrity (I)
    None
  • Availability (A)
    High
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Red Hat

5.5 medium