selftests/bpf: Add test for reading from STACK_INVALID slots

Ensure that when CAP_PERFMON is dropped, and the verifier sees
allow_ptr_leaks as false, we are not permitted to read from a
STACK_INVALID slot. Without the fix, the test will report unexpected
success in loading.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241204044757.1483141-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Kumar Kartikeya Dwivedi 2024-12-03 20:47:56 -08:00 committed by Alexei Starovoitov
parent adfdd9c685
commit f513c36350

View File

@ -1244,4 +1244,22 @@ __naked void old_stack_misc_vs_cur_ctx_ptr(void)
: __clobber_all);
}
SEC("socket")
__description("stack_noperfmon: reject read of invalid slots")
__success
__caps_unpriv(CAP_BPF)
__failure_unpriv __msg_unpriv("invalid read from stack off -8+1 size 8")
__naked void stack_noperfmon_reject_invalid_read(void)
{
asm volatile (" \
r2 = 1; \
r6 = r10; \
r6 += -8; \
*(u8 *)(r6 + 0) = r2; \
r2 = *(u64 *)(r6 + 0); \
r0 = 0; \
exit; \
" ::: __clobber_all);
}
char _license[] SEC("license") = "GPL";