CVE-2022-50135

/// Technical description

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

RDMA/rxe: Fix BUG: KASAN: null-ptr-deref in rxe_qp_do_cleanup

The function rxe_create_qp calls rxe_qp_from_init. If some error

occurs, the error handler of function rxe_qp_from_init will set

both scq and rcq to NULL.

Then rxe_create_qp calls rxe_put to handle qp. In the end,

rxe_qp_do_cleanup is called by rxe_put. rxe_qp_do_cleanup directly

accesses scq and rcq before checking them. This will cause

null-ptr-deref error.

The call graph is as below:

rxe_create_qp {

...

rxe_qp_from_init {

...

err1:

...

qp->rcq = NULL; <---rcq is set to NULL

qp->scq = NULL; <---scq is set to NULL

...

}

qp_init:

rxe_put{

...

rxe_qp_do_cleanup {

...

atomic_dec(&qp->scq->num_wq); <--- scq is accessed

...

atomic_dec(&qp->rcq->num_wq); <--- rcq is accessed

}

}

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References