From f17472d4599697d701aa239b4c475a506bccfd19 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Tue, 22 Nov 2022 19:54:22 -0800 Subject: [PATCH] bpf: Prevent decl_tag from being referenced in func_proto arg Syzkaller managed to hit another decl_tag issue: btf_func_proto_check kernel/bpf/btf.c:4506 [inline] btf_check_all_types kernel/bpf/btf.c:4734 [inline] btf_parse_type_sec+0x1175/0x1980 kernel/bpf/btf.c:4763 btf_parse kernel/bpf/btf.c:5042 [inline] btf_new_fd+0x65a/0xb00 kernel/bpf/btf.c:6709 bpf_btf_load+0x6f/0x90 kernel/bpf/syscall.c:4342 __sys_bpf+0x50a/0x6c0 kernel/bpf/syscall.c:5034 __do_sys_bpf kernel/bpf/syscall.c:5093 [inline] __se_sys_bpf kernel/bpf/syscall.c:5091 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5091 do_syscall_64+0x54/0x70 arch/x86/entry/common.c:48 This seems similar to commit ea68376c8bed ("bpf: prevent decl_tag from being referenced in func_proto") but for the argument. Reported-by: syzbot+8dd0551dda6020944c5d@syzkaller.appspotmail.com Signed-off-by: Stanislav Fomichev Signed-off-by: Daniel Borkmann Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/20221123035422.872531-2-sdf@google.com --- kernel/bpf/btf.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 1a59cc7..cb43cb8 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -4792,6 +4792,11 @@ static int btf_func_proto_check(struct btf_verifier_env *env, break; } + if (btf_type_is_resolve_source_only(arg_type)) { + btf_verifier_log_type(env, t, "Invalid arg#%u", i + 1); + return -EINVAL; + } + if (args[i].name_off && (!btf_name_offset_valid(btf, args[i].name_off) || !btf_name_valid_identifier(btf, args[i].name_off))) { -- 2.7.4