CVE-2024-43862

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

net: wan: fsl_qmc_hdlc: Convert carrier_lock spinlock to a mutex

The carrier_lock spinlock protects the carrier detection. While it is held, framer_get_status() is called which in turn takes a mutex. This is not correct and can lead to a deadlock.

A run with PROVE_LOCKING enabled detected the issue: [ BUG: Invalid wait context ] … c204ddbc (&framer->mutex){+.+.}-{3:3}, at: framer_get_status+0x40/0x78 other info that might help us debug this: context-{4:4} 2 locks held by ifconfig/146: #0: c0926a38 (rtnl_mutex){+.+.}-{3:3}, at: devinet_ioctl+0x12c/0x664 #1: c2006a40 (&qmc_hdlc->carrier_lock){….}-{2:2}, at: qmc_hdlc_framer_set_carrier+0x30/0x98

Avoid the spinlock usage and convert carrier_lock to a mutex.

Weakness

The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.

Affected Software

Extended Description

Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process. This can lead to data or memory corruption, denial of service, etc.

Potential Mitigations

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/25.html
• https://cwe.mitre.org/data/definitions/26.html
• https://cwe.mitre.org/data/definitions/27.html

References

• https://git.kernel.org/stable/c/c4d6a347ba7babdf9d90a0eb24048c266cae0532
• https://git.kernel.org/stable/c/f223d2b4acb7a45a6e0581cb380e1af1a6dc7ab9