Linux Kernel mlx5 Refcount Crash in Flow Rule Linking
CVE-2024-35960 Published on May 20, 2024
net/mlx5: Properly link new fs rules into the tree
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Properly link new fs rules into the tree
Previously, add_rule_fg would only add newly created rules from the
handle into the tree when they had a refcount of 1. On the other hand,
create_flow_handle tries hard to find and reference already existing
identical rules instead of creating new ones.
These two behaviors can result in a situation where create_flow_handle
1) creates a new rule and references it, then
2) in a subsequent step during the same handle creation references it
again,
resulting in a rule with a refcount of 2 that is not linked into the
tree, will have a NULL parent and root and will result in a crash when
the flow group is deleted because del_sw_hw_rule, invoked on rule
deletion, assumes node->parent is != NULL.
This happened in the wild, due to another bug related to incorrect
handling of duplicate pkt_reformat ids, which lead to the code in
create_flow_handle incorrectly referencing a just-added rule in the same
flow handle, resulting in the problem described above. Full details are
at [1].
This patch changes add_rule_fg to add new rules without parents into
the tree, properly initializing them and avoiding the crash. This makes
it more consistent with how rules are added to an FTE in
create_flow_handle.
Vulnerability Analysis
CVE-2024-35960 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, a high impact on integrity and availability.
Weakness Type
NULL Pointer Dereference
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.
Products Associated with CVE-2024-35960
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Affected Versions
Linux:- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below de0139719cdda82806a47580ca0df06fc85e0bd2 is affected.
- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below 1263b0b26077b1183c3c45a0a2479573a351d423 is affected.
- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below 3d90ca9145f6b97b38d0c2b6b30f6ca6af9c1801 is affected.
- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below 7aaee12b804c5e0374e7b132b6ec2158ff33dd64 is affected.
- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below 2e8dc5cffc844dacfa79f056dea88002312f253f is affected.
- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below 5cf5337ef701830f173b4eec00a4f984adeb57a0 is affected.
- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below adf67a03af39095f05d82050f15813d6f700159d is affected.
- Version 74491de937125d0c98c9b9c9208b4105717a3caa and below 7c6782ad4911cbee874e85630226ed389ff2e453 is affected.
- Version 4.10 is affected.
- Before 4.10 is unaffected.
- Version 4.19.313, <= 4.19.* is unaffected.
- Version 5.4.275, <= 5.4.* is unaffected.
- Version 5.10.216, <= 5.10.* is unaffected.
- Version 5.15.156, <= 5.15.* is unaffected.
- Version 6.1.87, <= 6.1.* is unaffected.
- Version 6.6.28, <= 6.6.* is unaffected.
- Version 6.8.7, <= 6.8.* is unaffected.
- Version 6.9, <= * is unaffected.
- Version 74491de93712 and below de0139719cdd is affected.
- Version 74491de93712 and below 3d90ca9145f6 is affected.
- Version 74491de93712 and below 7aaee12b804c is affected.
- Version 74491de93712 and below 2e8dc5cffc84 is affected.
- Version 74491de93712 and below 5cf5337ef701 is affected.
- Version 74491de93712 and below adf67a03af39 is affected.
- Version 74491de93712 and below 7c6782ad4911 is affected.
- Version 4.10 is affected.
- Before 4.10 is unaffected.
- Version 4.19.313, <= 4.20 is unaffected.
- Before and including 5.5 is unaffected.
- Version 5.10.216, <= 5.11 is unaffected.
- Version 5.15.156, <= 5.16 is unaffected.
- Version 6.1.87, <= 6.2 is unaffected.
- Version 6.6.28, <= 6.7 is unaffected.
- Version 6.8.7, <= 6.9 is unaffected.
- Version 6.9 is unaffected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.