Commit a37a3258 authored by Lorenz Bauer's avatar Lorenz Bauer Committed by Alexei Starovoitov
Browse files

bpf: btf: fix truncated last_member_type_id in btf_struct_resolve 



When trying to finish resolving a struct member, btf_struct_resolve
saves the member type id in a u16 temporary variable. This truncates
the 32 bit type id value if it exceeds UINT16_MAX.

As a result, structs that have members with type ids > UINT16_MAX and
which need resolution will fail with a message like this:

    [67414] STRUCT ff_device size=120 vlen=12
        effect_owners type_id=67434 bits_offset=960 Member exceeds struct_size

Fix this by changing the type of last_member_type_id to u32.

Fixes: a0791f0d ("bpf: fix BTF limits")
Reviewed-by: default avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: default avatarLorenz Bauer <oss@lmb.io>
Link: https://lore.kernel.org/r/20220910110120.339242-1-oss@lmb.io


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 8a7d61bd

kernel/bpf/btf.c

+1 −1
Original line number Diff line number Diff line
@@ -3128,7 +3128,7 @@ static int btf_struct_resolve(struct btf_verifier_env *env, 
	if (v->next_member) {

		const struct btf_type *last_member_type;

		const struct btf_member *last_member;

		u16 last_member_type_id;

		u32 last_member_type_id;



		last_member = btf_type_member(v->t) + v->next_member - 1;

		last_member_type_id = last_member->type;