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

bpf: Reject resilient lock operations in rbtree callbacks

__bpf_rbtree_add() keeps parent and link pointers live across calls to the program-supplied comparison callback. The verifier therefore requires the root's lock to remain held throughout the callback.

The helper path enforces this rule for bpf_spin_lock() and bpf_spin_unlock(), but the resilient lock kfunc argument path does not. Since resilient locks may protect BPF rbtree roots, a callback can release the root lock and let another CPU remove and free the node referenced by the in-progress tree walk. The walk then resumes using freed pointers.

Reject resilient lock kfuncs in an rbtree comparison callback, matching the existing policy for the spin lock helpers. Resilient-lock-protected trees remain valid when their comparison callbacks leave lock state alone.

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

bpf: Reject resilient lock operations in rbtree callbacks

__bpf_rbtree_add() keeps parent and link pointers live across calls to the program-supplied comparison callback. The verifier therefore requires the root's lock to remain held throughout the callback.

The helper path enforces this rule for bpf_spin_lock() and bpf_spin_unlock(), but the resilient lock kfunc argument path does not. Since resilient locks may protect BPF rbtree roots, a callback can release the root lock and let another CPU remove and free the node referenced by the in-progress tree walk. The walk then resumes using freed pointers.

Reject resilient lock kfuncs in an rbtree comparison callback, matching the existing policy for the spin lock helpers. Resilient-lock-protected trees remain valid when their comparison callbacks leave lock state alone.

Affected: Ubuntu:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe and 246 more

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject resilient lock operations in rbtree callbacks __bpf_rbtree_add() keeps parent and link pointers live across calls to the program-supplied comparison callback. The verifier therefore requires the root's lock to remain held throughout the callback. The helper path enforces this rule for bpf_spin_lock() and bpf_spin_unlock(), but the resilient lock kfunc argument path does not. Since resilient locks may protect BPF rbtree roots, a callback can release the root lock and let another CPU remove and free the node referenced by the in-progress tree walk. The walk then resumes using freed pointers. Reject resilient lock kfuncs in an rbtree comparison callback, matching the existing policy for the spin lock helpers. Resilient-lock-protected trees remain valid when their comparison callbacks leave lock state alone.

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service Zustand herbeizuführen oder nicht näher spezifizierten Angriff durchzuführen.