CVE-2022-49524

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

media: pci: cx23885: Fix the error handling in cx23885_initdev()

When the driver fails to call the dma_set_mask(), the driver will get the following splat:

[ 55.853884] BUG: KASAN: use-after-free in __process_removed_driver+0x3c/0x240 [ 55.854486] Read of size 8 at addr ffff88810de60408 by task modprobe/590 [ 55.856822] Call Trace: [ 55.860327] __process_removed_driver+0x3c/0x240 [ 55.861347] bus_for_each_dev+0x102/0x160 [ 55.861681] i2c_del_driver+0x2f/0x50

This is because the driver has initialized the i2c related resources in cx23885_dev_setup() but not released them in error handling, fix this bug by modifying the error path that jumps after failing to call the dma_set_mask().

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/453514a874c78df1e7804e6e3aaa60c8d8deb6a8
• https://git.kernel.org/stable/c/6041d1a0365baa729b6adfb6ed5386d9388018db
• https://git.kernel.org/stable/c/7b9978e1c94e569d65a0e7e719abb9340f5db4a0
• https://git.kernel.org/stable/c/86bd6a579c6c60547706cabf299cd2c9feab3332
• https://git.kernel.org/stable/c/98106f100f50c487469903b9cf6d966785fc9cc3
• https://git.kernel.org/stable/c/ca17e7a532d1a55466cc007b3f4d319541a27493
• https://git.kernel.org/stable/c/e8123311cf06d7dae71e8c5fe78e0510d20cd30b
• https://git.kernel.org/stable/c/fa636e9ee4442215cd9a2e079cd5a8e1fe0cb8ba