Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject untrusted allocated-object pointers When the final RCU read-side critical section ends, a local kptr is demoted to PTR_UNTRUSTED but retains MEM_ALLOC. The pointer may be NULL or may refer to an object whose lifetime is no longer protected. type_is_ptr_alloc_obj() nevertheless recognizes any PTR_TO_BTF_ID with MEM_ALLOC as a live allocated object. In particular, a refcount-only local kptr never carries NON_OWN_REF, so it still passes the bpf_refcount_acquire() argument check after RCU protection ends. The kfunc can then dereference NULL or stale memory. Make type_is_ptr_alloc_obj() reject PTR_UNTRUSTED pointers. Since type_is_non_owning_ref() is based on the same predicate, graph kfunc arguments obey the same live-object requirement. Fault-protected reads of the demoted pointer remain valid: writes are already rejected, and read fixups use bpf_may_fault_on_deref() rather than this predicate. [ kkd: Rewrote commit log ]
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected 1b12171533a9bb23cf6fba7262b479028b65e1e8 before 092c2874dc1b2060fa77a465a971acd4fdf87683; affected 1b12171533a9bb23cf6fba7262b479028b65e1e8 before 135d542b97fa93e32c457d49d6e7b33ca7d05bae; affected 1b12171533a9bb23cf6fba7262b479028b65e1e8 before 6b1f786ad85a0b63393b76f5e634deab1a73198c; affected 1b12171533a9bb23cf6fba7262b479028b65e1e8 before 7441ee8276641bddaf1cba7bb75ef9c1458ceb3b |
| Linux / Linux | affected 6.8; unaffected 0 before 6.8; unaffected 6.12.111 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.