CVE-2024-40903

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

usb: typec: tcpm: fix use-after-free case in tcpm_register_source_caps

There could be a potential use-after-free case in tcpm_register_source_caps(). This could happen when:

• new (say invalid) source caps are advertised
• the existing source caps are unregistered
• tcpm_register_source_caps() returns with an error as usb_power_delivery_register_capabilities() fails

This causes port->partner_source_caps to hold on to the now freed source caps.

Reset port->partner_source_caps value to NULL after unregistering existing source caps.

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/04c05d50fa79a41582f7bde8a1fd4377ae4a39e5
• https://git.kernel.org/stable/c/4053696594d7235f3638d49a00cf0f289e4b36a3
• https://git.kernel.org/stable/c/6b67b652849faf108a09647c7fde9b179ef24e2b
• https://git.kernel.org/stable/c/e7e921918d905544500ca7a95889f898121ba886