CVE-2022-48791

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

scsi: pm8001: Fix use-after-free for aborted TMF sas_task

Currently a use-after-free may occur if a TMF sas_task is aborted before we handle the IO completion in mpi_ssp_completion(). The abort occurs due to timeout.

When the timeout occurs, the SAS_TASK_STATE_ABORTED flag is set and the sas_task is freed in pm8001_exec_internal_tmf_task().

However, if the I/O completion occurs later, the I/O completion still thinks that the sas_task is available. Fix this by clearing the ccb->task if the TMF times out - the I/O completion handler does nothing if this pointer is cleared.

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/3c334cdfd94945b8edb94022a0371a8665b17366
• https://git.kernel.org/stable/c/510b21442c3a2e3ecc071ba3e666b320e7acdd61
• https://git.kernel.org/stable/c/61f162aa4381845acbdc7f2be4dfb694d027c018
• https://git.kernel.org/stable/c/d872e7b5fe38f325f5206b6872746fa02c2b4819