Stack-based Buffer Overflow Affecting kernel-core package, versions *


Severity

Recommended
low

Based on Red Hat Enterprise Linux security rating

    Threat Intelligence

    EPSS
    0.04% (14th percentile)

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  • Snyk ID SNYK-RHEL9-KERNELCORE-7584524
  • published 5 Aug 2024
  • disclosed 29 Jul 2024

How to fix?

There is no fixed version for RHEL:9 kernel-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-core package and not the kernel-core package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

netfilter: nf_tables: prefer nft_chain_validate

nft_chain_validate already performs loop detection because a cycle will result in a call stack overflow (ctx->level >= NFT_JUMP_STACK_SIZE).

It also follows maps via ->validate callback in nft_lookup, so there appears no reason to iterate the maps again.

nf_tables_check_loops() and all its helper functions can be removed. This improves ruleset load time significantly, from 23s down to 12s.

This also fixes a crash bug. Old loop detection code can result in unbounded recursion:

BUG: TASK stack guard page was hit at .... Oops: stack guard page: 0000 [#1] PREEMPT SMP KASAN CPU: 4 PID: 1539 Comm: nft Not tainted 6.10.0-rc5+ #1 [..]

with a suitable ruleset during validation of register stores.

I can't see any actual reason to attempt to check for this from nft_validate_register_store(), at this point the transaction is still in progress, so we don't have a full picture of the rule graph.

For nf-next it might make sense to either remove it or make this depend on table->validate_state in case we could catch an error earlier (for improved error reporting to userspace).

CVSS Scores

version 3.1
Expand this section

Red Hat

4.1 medium
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    High
  • Privileges Required (PR)
    High
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    None
  • Integrity (I)
    None
  • Availability (A)
    High
Expand this section

SUSE

4.4 medium