Linux Kernel up to 5.15.4 flow_put allocation of resources

Summaryinfo

A vulnerability marked as problematic has been reported in Linux Kernel up to 5.15.4. Affected by this issue is the function flow_put. The manipulation leads to allocation of resources. This vulnerability is uniquely identified as CVE-2021-47199. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 5.15.4. This issue affects the function flow_put. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: CT, Fix multiple allocations and memleak of mod acts CT clear action offload adds additional mod hdr actions to the flow's original mod actions in order to clear the registers which hold ct_state. When such flow also includes encap action, a neigh update event can cause the driver to unoffload the flow and then reoffload it. Each time this happens, the ct clear handling adds that same set of mod hdr actions to reset ct_state until the max of mod hdr actions is reached. Also the driver never releases the allocated mod hdr actions and causing a memleak. Fix above two issues by moving CT clear mod acts allocation into the parsing actions phase and only use it when offloading the rule. The release of mod acts will be done in the normal flow_put(). backtrace: [] krealloc+0x83/0xd0 [] mlx5e_mod_hdr_alloc+0x147/0x300 [mlx5_core] [] mlx5e_tc_match_to_reg_set_and_get_id+0xd7/0x240 [mlx5_core] [] mlx5e_tc_match_to_reg_set+0xa/0x20 [mlx5_core] [] mlx5_tc_ct_entry_set_registers.isra.0+0x36/0xc0 [mlx5_core] [] mlx5_tc_ct_flow_offload+0x272/0x1f10 [mlx5_core] [] mlx5e_tc_offload_fdb_rules.part.0+0x150/0x620 [mlx5_core] [] mlx5e_tc_encap_flows_add+0x489/0x690 [mlx5_core] [] mlx5e_rep_update_flows+0x6e4/0x9b0 [mlx5_core] [] mlx5e_rep_neigh_update+0x39a/0x5d0 [mlx5_core]

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2021-47199 since 03/25/2024. The exploitation is known to be difficult. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 5.15.5 or 5.16 eliminates this vulnerability. Applying the patch 486e8de6e233/806401c20a0f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.15.0
• 5.15.1
• 5.15.2
• 5.15.3
• 5.15.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

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CPE 2.2info

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