CVE-2024-26924 — netfilter: nft_set_pipapo: do not free live element

Affected: Linux, linux_kernel

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

netfilter: nft_set_pipapo: do not free live element

Pablo reports a crash with large batches of elements with a back-to-back add/remove pattern. Quoting Pablo:

add_elem("00000000") timeout 100 ms ... add_elem("0000000X") timeout 100 ms del_elem("0000000X") <---------------- delete one that was just added ... add_elem("00005000") timeout 100 ms

1) nft_pipapo_remove() removes element 0000000X Then, KASAN shows a splat.

Looking at the remove function there is a chance that we will drop a rule that maps to a non-deactivated element.

Removal happens in two steps, first we do a lookup for key k and return the to-be-removed element and mark it as inactive in the next generation. Then, in a second step, the element gets removed from the set/map.

The _remove function does not work correctly if we have more than one element that share the same key.

This can happen if we insert an element into a set when the set already holds an element with same key, but the element mapping to the existing key has timed out or is not active in the next generation.

In such case its possible that removal will unmap the wrong element. If this happens, we will leak the non-deactivated element, it becomes unreachable.

The element that got deactivated (and will be freed later) will remain reachable in the set data structure, this can result in a crash when such an element is retrieved during lookup (stale pointer)…

LSN-0105-1 — Kernel Live Patch Security Notice

Affected: Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:18.04:LTS: linux-aws, Ubuntu:Pro:18.04:LTS: linux-azure-4.15, Ubuntu:Pro:18.04:LTS: linux-gcp-4.15 and 29 more

It was discovered that the ATA over Ethernet (AoE) driver in the Linux kernel contained a race condition, leading to a use-after-free vulnerability. An attacker could use this to cause a denial of service or possibly execute arbitrary code.(CVE-2023-6270)

It was discovered that the netfilter connection tracker for netlink in the Linux kernel did not properly perform reference counting in some error conditions. A local attacker could possibly use this to cause a denial of service (memory exhaustion).(CVE-2023-7192)

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: disallow anonymous set with timeout flag Anonymous sets are never used with timeout from userspace, reject this. Exception to this rule is NFT_SET_EVAL to ensure legacy meters still work.(CVE-2024-26642)

In the Linux kernel, the following vulnerability has been resolved: cifs: fix underflow in parse_server_interfaces() In this loop, we step through the buffer and after each item we check if the size_left is greater than the minimum size we need. However, the problem is that 'bytes_left' is type ssize_t while sizeof() is type size_t. That means that because of type promotion, the comparison is done as an unsigned and if we have negative bytes left the loop continues instead of ending.(CVE-2024-26828)

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_set_pipapo: do not free live element (CVE-2024-26924)

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CVE-2024-26924 — netfilter: nft_set_pipapo: do not free live element

LSN-0105-1 — Kernel Live Patch Security Notice