Linux vulnerability

What happened

In the Linux kernel, the following vulnerability has been resolved: RDMA/rtrs: Fix use-after-free in path file creation cleanup In the error path of rtrs_srv_create_path_files(), the sysfs root folders may already have been created and srv_path->kobj may already have been initialized. If a later step fails, the cleanup currently calls kobject_put(&srv_path->kobj) before rtrs_srv_destroy_once_sysfs_root_folders(srv_path). kobject_put() may drop the last reference to srv_path->kobj and invoke the release callback, rtrs_srv_release(), which frees srv_path. The following call to rtrs_srv_destroy_once_sysfs_root_folders(srv_path) then dereferences srv_path internally to access srv_path->srv, resulting in a use-after-free. This failure path is reached before rtrs_srv_create_path_files() returns success, so the successful-path lifetime handling is not involved. Fix this by destroying the sysfs root folders before calling kobject_put(&srv_path->kobj), so srv_path is still valid while the helper accesses it. This issue was found by a static analysis tool I am developing.

Affected versions

Linux: bab17b761c8974a869b04462be5d4dd9aad366b4 through before 01e42aabaf7632beb4bf235c7238b96c746d4144 (git); ae4c81644e9105d9f7f713bb0d444737bb6a0cf1 through before 548f3956e53a7f7bde912d8129010b8986d5e602 (git); ae4c81644e9105d9f7f713bb0d444737bb6a0cf1 through before 00904a73272b9f3ef3952fe69a833909dccad1ef (git); ae4c81644e9105d9f7f713bb0d444737bb6a0cf1 through before 92060ab1c5115674cf319175550f85f68405121f (git); ae4c81644e9105d9f7f713bb0d444737bb6a0cf1 through before eae62c5451e67e8b033c1681fd3b85d7e9a9a28f (git); ae4c81644e9105d9f7f713bb0d444737bb6a0cf1 through before b0e9706fb2859064bb6c677554c4d20c713aa8e0 (git); ae4c81644e9105d9f7f713bb0d444737bb6a0cf1 through before 5b74373390113fba798a76b483837029ab010fef (git); 5.15.61 through before 5.15.209 (semver); 5.17 Fixed: See vendor advisory.

Why it matters

Review the vendor advisory and exposure of the affected product to determine operational impact.

Detection & mitigation

• Apply vendor-provided updates or mitigations.
• Review affected product exposure and access logs.