On Fri, Jun 16, 2023 at 06:17:22PM +0100, Alan Maguire wrote:
SNIP
> static int btf_sec_info_cmp(const void *a, const void *b)
> @@ -5193,32 +5246,37 @@ static int btf_check_sec_info(struct btf_verifier_env *env,
> u32 btf_data_size)
> {
> struct btf_sec_info secs[ARRAY_SIZE(btf_sec_info_offset)];
> - u32 total, expected_total, i;
> + u32 nr_secs = ARRAY_SIZE(btf_sec_info_offset);
> + u32 total, expected_total, gap, i;
> const struct btf_header *hdr;
> const struct btf *btf;
>
> btf = env->btf;
> hdr = &btf->hdr;
>
> + if (hdr->hdr_len < sizeof(struct btf_header))
> + nr_secs--;
> +
> /* Populate the secs from hdr */
> - for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++)
> + for (i = 0; i < nr_secs; i++)
> secs[i] = *(struct btf_sec_info *)((void *)hdr +
> btf_sec_info_offset[i]);
>
> - sort(secs, ARRAY_SIZE(btf_sec_info_offset),
> + sort(secs, nr_secs,
> sizeof(struct btf_sec_info), btf_sec_info_cmp, NULL);
>
> /* Check for gaps and overlap among sections */
> total = 0;
> expected_total = btf_data_size - hdr->hdr_len;
> - for (i = 0; i < ARRAY_SIZE(btf_sec_info_offset); i++) {
> + for (i = 0; i < nr_secs; i++) {
> if (expected_total < secs[i].off) {
> btf_verifier_log(env, "Invalid section offset");
> return -EINVAL;
> }
> - if (total < secs[i].off) {
> - /* gap */
> - btf_verifier_log(env, "Unsupported section found");
> + gap = secs[i].off - total;
> + if (gap >= 4) {
> + /* gap larger than alignment gap */
> + btf_verifier_log(env, "Unsupported section gap found");
> return -EINVAL;
this sems to break several btf header tests with:
do_test_raw:PASS:check 0 nsec
do_test_raw:FAIL:check expected err_str:Unsupported section found
magic: 0xeb9f
version: 1
flags: 0x0
hdr_len: 40
type_off: 4
type_len: 16
str_off: 16
str_len: 5
btf_total_size: 61
Unsupported section gap found
#23/48 btf/btf_header test. Gap between hdr and type:FAIL
jirka
> }
> if (total > secs[i].off) {
> @@ -5230,7 +5288,7 @@ static int btf_check_sec_info(struct btf_verifier_env *env,
> "Total section length too long");
> return -EINVAL;
> }
> - total += secs[i].len;
> + total += secs[i].len + gap;
> }
>
> /* There is data other than hdr and known sections */
> @@ -5293,7 +5351,7 @@ static int btf_parse_hdr(struct btf_verifier_env *env)
> return -ENOTSUPP;
> }
>
> - if (hdr->flags) {
> + if (hdr->flags & ~(BTF_FLAG_CRC_SET | BTF_FLAG_BASE_CRC_SET)) {
> btf_verifier_log(env, "Unsupported flags");
> return -ENOTSUPP;
> }
> @@ -5530,6 +5588,10 @@ static struct btf *btf_parse(const union bpf_attr *attr, bpfptr_t uattr, u32 uat
> if (err)
> goto errout;
>
> + err = btf_parse_kind_layout_sec(env);
> + if (err)
> + goto errout;
> +
> err = btf_parse_type_sec(env);
> if (err)
> goto errout;
> --
> 2.39.3
>
