diff options
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_subprog_precision.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c b/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c index b5efcaeaa1ae..d41d2a8bb97e 100644 --- a/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c +++ b/tools/testing/selftests/bpf/progs/verifier_subprog_precision.c @@ -117,6 +117,56 @@ __naked int global_subprog_result_precise(void) ); } +__naked __noinline __used +static unsigned long loop_callback_bad() +{ + /* bpf_loop() callback that can return values outside of [0, 1] range */ + asm volatile ( + "call %[bpf_get_prandom_u32];" + "if r0 s> 1000 goto 1f;" + "r0 = 0;" + "1:" + "goto +0;" /* checkpoint */ + /* bpf_loop() expects [0, 1] values, so branch above skipping + * r0 = 0; should lead to a failure, but if exit instruction + * doesn't enforce r0's precision, this callback will be + * successfully verified + */ + "exit;" + : + : __imm(bpf_get_prandom_u32) + : __clobber_common + ); +} + +SEC("?raw_tp") +__failure __log_level(2) +__flag(BPF_F_TEST_STATE_FREQ) +/* check that fallthrough code path marks r0 as precise */ +__msg("mark_precise: frame1: regs=r0 stack= before 11: (b7) r0 = 0") +/* check that we have branch code path doing its own validation */ +__msg("from 10 to 12: frame1: R0=scalar(smin=umin=1001") +/* check that branch code path marks r0 as precise, before failing */ +__msg("mark_precise: frame1: regs=r0 stack= before 9: (85) call bpf_get_prandom_u32#7") +__msg("At callback return the register R0 has value (0x0; 0x7fffffffffffffff) should have been in (0x0; 0x1)") +__naked int callback_precise_return_fail(void) +{ + asm volatile ( + "r1 = 1;" /* nr_loops */ + "r2 = %[loop_callback_bad];" /* callback_fn */ + "r3 = 0;" /* callback_ctx */ + "r4 = 0;" /* flags */ + "call %[bpf_loop];" + + "r0 = 0;" + "exit;" + : + : __imm_ptr(loop_callback_bad), + __imm(bpf_loop) + : __clobber_common + ); +} + SEC("?raw_tp") __success __log_level(2) /* First simulated path does not include callback body, |