| Message ID | 20220312171354.661448-1-ytcoode@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] libbpf: Remove redundant check in btf_ext__new() | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Clearly marked for bpf-next |
| netdev/fixes_present | success | Fixes tag not required for -next series |
| netdev/subject_prefix | success | Link |
| netdev/cover_letter | success | Single patches do not need cover letters |
| netdev/patch_count | success | Link |
| netdev/header_inline | success | No static functions without inline keyword in header files |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/cc_maintainers | success | CCed 10 of 10 maintainers |
| netdev/build_clang | success | Errors and warnings before: 0 this patch: 0 |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Signed-off-by tag matches author and committer |
| netdev/verify_fixes | success | No Fixes tag |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/checkpatch | warning | WARNING: line length of 88 exceeds 80 columns |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/source_inline | success | Was 0 now: 0 |
| bpf/vmtest-bpf-next-PR | success | PR summary |
| bpf/vmtest-bpf-next | success | VM_Test |
On Sat, Mar 12, 2022 at 9:14 AM Yuntao Wang <ytcoode@gmail.com> wrote: > > Since 'core_relo_len' is the last field of 'struct btf_ext_header', if > 'xxx->hdr_len' is not less than 'offsetofend(xxx, core_relo_len)', then > 'xxx->hdr_len' must also be not less than 'offsetofend(xxx, line_info_len)'. > > We can check 'xxx->hdr_len < offsetofend(xxx, core_relo_len)' first, if it > passes, the 'xxx->hdr_len < offsetofend(xxx, line_info_len)' check will be > redundant, it can be removed. > > Signed-off-by: Yuntao Wang <ytcoode@gmail.com> > --- > tools/lib/bpf/btf.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c > index 1383e26c5d1f..d55b44124c3e 100644 > --- a/tools/lib/bpf/btf.c > +++ b/tools/lib/bpf/btf.c > @@ -2813,7 +2813,7 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) > if (err) > goto done; > > - if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, line_info_len)) { > + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) { > err = -EINVAL; > goto done; > } > @@ -2826,11 +2826,6 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) > if (err) > goto done; > > - if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) { > - err = -EINVAL; > - goto done; > - } it seems like it's actually a bug. If header is smaller then core relos parsing should be skipped, I think. Maybe let's fix that instead? basically the logic should be: 1. if size of header is exactly == offsetof(core_relo_off) then skip core relos 2. otherwise check that it has enough size to cover core_relo_off and core_relo_len, and error out if not 3. otherwise proceed to parsing core relos > - > err = btf_ext_setup_core_relos(btf_ext); > if (err) > goto done; > -- > 2.35.1 >
diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 1383e26c5d1f..d55b44124c3e 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -2813,7 +2813,7 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) if (err) goto done; - if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, line_info_len)) { + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) { err = -EINVAL; goto done; } @@ -2826,11 +2826,6 @@ struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) if (err) goto done; - if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, core_relo_len)) { - err = -EINVAL; - goto done; - } - err = btf_ext_setup_core_relos(btf_ext); if (err) goto done;
Since 'core_relo_len' is the last field of 'struct btf_ext_header', if 'xxx->hdr_len' is not less than 'offsetofend(xxx, core_relo_len)', then 'xxx->hdr_len' must also be not less than 'offsetofend(xxx, line_info_len)'. We can check 'xxx->hdr_len < offsetofend(xxx, core_relo_len)' first, if it passes, the 'xxx->hdr_len < offsetofend(xxx, line_info_len)' check will be redundant, it can be removed. Signed-off-by: Yuntao Wang <ytcoode@gmail.com> --- tools/lib/bpf/btf.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-)