CVE-2024-26898

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

aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts

This patch is against CVE-2023-6270. The description of cve is:

A flaw was found in the ATA over Ethernet (AoE) driver in the Linux kernel. The aoecmd_cfg_pkts() function improperly updates the refcnt on struct net_device, and a use-after-free can be triggered by racing between the free on the struct and the access through the skbtxq global queue. This could lead to a denial of service condition or potential code execution.

In aoecmd_cfg_pkts(), it always calls dev_put(ifp) when skb initial code is finished. But the net_device ifp will still be used in later tx()->dev_queue_xmit() in kthread. Which means that the dev_put(ifp) should NOT be called in the success path of skb initial code in aoecmd_cfg_pkts(). Otherwise tx() may run into use-after-free because the net_device is freed.

This patch removed the dev_put(ifp) in the success path in aoecmd_cfg_pkts(), and added dev_put() after skb xmit in tx().

Weakness

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

Affected Software

Extended Description

The use of previously-freed memory can have any number of adverse consequences, ranging from the corruption of valid data to the execution of arbitrary code, depending on the instantiation and timing of the flaw. The simplest way data corruption may occur involves the system’s reuse of the freed memory. Use-after-free errors have two common and sometimes overlapping causes:

In this scenario, the memory in question is allocated to another pointer validly at some point after it has been freed. The original pointer to the freed memory is used again and points to somewhere within the new allocation. As the data is changed, it corrupts the validly used memory; this induces undefined behavior in the process. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential Mitigations

References

• https://git.kernel.org/stable/c/079cba4f4e307c69878226fdf5228c20aa1c969c
• https://git.kernel.org/stable/c/1a54aa506b3b2f31496731039e49778f54eee881
• https://git.kernel.org/stable/c/74ca3ef68d2f449bc848c0a814cefc487bf755fa
• https://git.kernel.org/stable/c/7dd09fa80b0765ce68bfae92f4e2f395ccf0fba4
• https://git.kernel.org/stable/c/a16fbb80064634b254520a46395e36b87ca4731e
• https://git.kernel.org/stable/c/ad80c34944d7175fa1f5c7a55066020002921a99
• https://git.kernel.org/stable/c/eb48680b0255a9e8a9bdc93d6a55b11c31262e62
• https://git.kernel.org/stable/c/f98364e926626c678fb4b9004b75cacf92ff0662
• https://git.kernel.org/stable/c/faf0b4c5e00bb680e8e43ac936df24d3f48c8e65