From 591065e7664b61b1d937bc8cf03da2e1397558ff Mon Sep 17 00:00:00 2001 From: Lorenz Bauer Date: Sat, 10 Sep 2022 11:01:20 +0000 Subject: [PATCH] bpf: btf: fix truncated last_member_type_id in btf_struct_resolve BugLink: https://bugs.launchpad.net/bugs/1996825 [ 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 Signed-off-by: Lorenz Bauer Link: https://lore.kernel.org/r/20220910110120.339242-1-oss@lmb.io Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin Signed-off-by: Kamal Mostafa Signed-off-by: Stefan Bader --- 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 3cfba41a0829..7cb13b9f69a6 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -2983,7 +2983,7 @@ 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; -- 2.39.5