Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject tail calls directly from callback frames A tail call from a non-zero frame is modeled as a return from that frame. The verifier makes R0 unknown and calls prepare_func_exit() for the taken branch. When the current frame is a synchronous callback, prepare_func_exit() enforces the callback return-value contract and marks R0 precise. Since the tail-call path synthesized R0 rather than deriving it from an instruction, precision backtracking reaches the callback-calling instruction with R0 still requested and triggers the "callback unexpected regs" verifier bug. A CAP_BPF task can therefore cause a WARN and an -EFAULT BPF_PROG_LOAD. Tail calls reachable from callbacks are already rejected later by check_max_stack_depth(). Reject a tail call made directly by a callback before constructing the inconsistent return state, using the existing diagnostic. Tail calls from ordinary subprograms keep their current behavior.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected a6c22c91b6284e4713c0cf5b20ab3c9c71b77ae8 before 617c8266e49f45747f71e74177646a63f72b7025; affected e3245f8990431950d20631c72236d4e8cb2dcde8 before 96d31b28263c429a56e4de85bcf744a5c320b3a3; affected e3245f8990431950d20631c72236d4e8cb2dcde8 before 266aa4ad0b2e82397cd9045752c9bff03d98eddd; affected 6.18.2 before 6.18.53 |
| Linux / Linux | affected 6.19; unaffected 0 before 6.19; unaffected 6.18.53 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.