CVE-2024-49982

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

aoe: fix the potential use-after-free problem in more places

For fixing CVE-2023-6270, f98364e92662 (aoe: fix the potential use-after-free problem in aoecmd_cfg_pkts) makes tx() calling dev_put() instead of doing in aoecmd_cfg_pkts(). It avoids that the tx() runs into use-after-free.

Then Nicolai Stange found more places in aoe have potential use-after-free problem with tx(). e.g. revalidate(), aoecmd_ata_rw(), resend(), probe() and aoecmd_cfg_rsp(). Those functions also use aoenet_xmit() to push packet to tx queue. So they should also use dev_hold() to increase the refcnt of skb->dev.

On the other hand, moving dev_put() to tx() causes that the refcnt of skb->dev be reduced to a negative value, because corresponding dev_hold() are not called in revalidate(), aoecmd_ata_rw(), resend(), probe(), and aoecmd_cfg_rsp(). This patch fixed this issue.

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/07b418d50ccbbca7e5d87a3a0d41d436cefebf79
• https://git.kernel.org/stable/c/12f7b89dd72b25da4eeaa22097877963cad6418e
• https://git.kernel.org/stable/c/6d6e54fc71ad1ab0a87047fd9c211e75d86084a3
• https://git.kernel.org/stable/c/8253a60c89ec35c8f36fb2cc08cdf854c7a3eb58
• https://git.kernel.org/stable/c/89d9a69ae0c667e4d9d028028e2dcc837bae626f
• https://git.kernel.org/stable/c/a786265aecf39015418e4f930cc1c14603a01490
• https://git.kernel.org/stable/c/acc5103a0a8c200a52af7d732c36a8477436a3d3
• https://git.kernel.org/stable/c/bc2cbf7525ac288e07d465f5a1d8cb8fb9599254
• https://git.kernel.org/stable/c/f63461af2c1a86af4217910e47a5c46e3372e645