Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject non-scalar bpf_loop iteration counts bpf_loop() declares its nr_loops argument as ARG_ANYTHING. Privileged programs may pass pointer values to such arguments, so check_func_arg() lets a pointer-valued R1 reach the helper-specific checks. Since commit bb124da69c47 ("bpf: keep track of max number of bpf_loop callback iterations"), the verifier marks R1 precise and reads its upper bound to limit callback simulation. Precision backtracking only accepts scalar registers, so passing a pointer instead triggers the "backtracking misuse" verifier warning. Kernels with panic_on_warn enabled subsequently panic. Introduce ARG_SCALAR for helper arguments that only accept scalar values and use it for bpf_loop() nr_loops. Generic helper argument validation then rejects pointers before loop inlining and precision processing.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected bfc5c19b4b48840627af0d0f1c8f4461b276e508 before 2ff38b3552af53238aee6c877ae64cc798d46fce; affected bb124da69c47dd98d69361ec13244ece50bec63e before 656d40d1ca228ee21a9b3280432479fc9eae75ab; affected bb124da69c47dd98d69361ec13244ece50bec63e before e2e1161e03fecff6d2229a81b024337144bfcd97; affected bb124da69c47dd98d69361ec13244ece50bec63e before f8ae8275c721334ee50fafdd986fb83294eb941a; affected bb124da69c47dd98d69361ec13244ece50bec63e before c3fd8e5fd100f122bad503bdc0e9277219533253; affected 6.6.15 before 6.6.158 |
| Linux / Linux | affected 6.7; unaffected 0 before 6.7; unaffected 6.6.158 through 6.6.*; 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.
References
- https://git.kernel.org/stable/c/2ff38b3552af53238aee6c877ae64cc798d46fce
- https://git.kernel.org/stable/c/656d40d1ca228ee21a9b3280432479fc9eae75ab
- https://git.kernel.org/stable/c/e2e1161e03fecff6d2229a81b024337144bfcd97
- https://git.kernel.org/stable/c/f8ae8275c721334ee50fafdd986fb83294eb941a
- https://git.kernel.org/stable/c/c3fd8e5fd100f122bad503bdc0e9277219533253