From: Lorenz Bauer oss@lmb.io
[ Upstream commit a37a32583e282d8d815e22add29bc1e91e19951a ]
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: a0791f0df7d2 ("bpf: fix BTF limits") Reviewed-by: Stanislav Fomichev sdf@google.com Signed-off-by: Lorenz Bauer oss@lmb.io Link: https://lore.kernel.org/r/20220910110120.339242-1-oss@lmb.io Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 7e64447659f3..36fd4b509294 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -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;