diff options
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c b/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c index 8657e4a0d601..410acbf658c7 100644 --- a/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c +++ b/tools/testing/selftests/bpf/progs/verifier_jeq_infer_not_null.c @@ -391,6 +391,33 @@ __naked void bounded_offset_infers_map_value_non_null(void) : __clobber_all); } +/* + * The low 32 bits of a map value pointer may be zero, hence a 32-bit + * compare with zero cannot be predicted from the pointer being non-NULL + * and both successors of such a jump have to be verified. + */ +SEC("socket") +__failure __msg("invalid access to map value, value_size=4 off=32 size=4") +__naked void jmp32_ptr_vs_zero_jne(void) +{ + asm volatile (" \ + /* r0 = bpf_map_lookup_elem(map_hash, &key); */ \ + *(u64 *)(r10 - 8) = 0; \ + r1 = %[map_hash] ll; \ + r2 = r10; \ + r2 += -8; \ + call %[bpf_map_lookup_elem]; \ + if r0 == 0 goto 1f; \ + if w0 != 0 goto 1f; \ + r0 = *(u32 *)(r0 + 32); \ +1: r0 = 0; \ + exit; \ +" : + : __imm(bpf_map_lookup_elem), + __imm_addr(map_hash) + : __clobber_all); +} + void kfunc_root(void) { bpf_rdonly_cast(0, 0); |