bpf: Fix bpf_attr.attach_btf_id check

Only raw_tracepoint program type can have bpf_attr.attach_btf_id >= 0.
Make sure to reject other program types that accidentally set it to non-zero.

Fixes: ccfe29eb29c2 ("bpf: Add attach_btf_id attribute to program load")
Reported-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20191018060933.2950231-1-ast@kernel.org

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 523e3ac15a0808b4a5ca19daafeff4135d352b37..16ea3c0db4f61e355c45930b21edd5acabc31aba 100644 (file)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1570,6 +1570,17 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
                           enum bpf_attach_type expected_attach_type,
                           u32 btf_id)
 {
+       switch (prog_type) {
+       case BPF_PROG_TYPE_RAW_TRACEPOINT:
+               if (btf_id > BTF_MAX_TYPE)
+                       return -EINVAL;
+               break;
+       default:
+               if (btf_id)
+                       return -EINVAL;
+               break;
+       }
+
        switch (prog_type) {
        case BPF_PROG_TYPE_CGROUP_SOCK:
                switch (expected_attach_type) {
@@ -1610,13 +1621,7 @@ bpf_prog_load_check_attach(enum bpf_prog_type prog_type,
                default:
                        return -EINVAL;
                }
-       case BPF_PROG_TYPE_RAW_TRACEPOINT:
-               if (btf_id > BTF_MAX_TYPE)
-                       return -EINVAL;
-               return 0;
        default:
-               if (btf_id)
-                       return -EINVAL;
                return 0;
        }
 }