bpf: program: Refuse non-O_RDWR flags in BPF_OBJ_GET

As for bpf_link, refuse creating a non-O_RDWR fd. Since program fds currently don't allow modifications this is a precaution, not a straight up bug fix. Signed-off-by: Lorenz Bauer <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Acked-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
ambv · Apr 1, 2021 · d37300e · d37300e
1 parent 25fc94b
commit d37300e
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
@@ -543,7 +543,7 @@ int bpf_obj_get_user(const char __user *pathname, int flags)
 		return PTR_ERR(raw);
 
 	if (type == BPF_TYPE_PROG)
-		ret = bpf_prog_new_fd(raw);
+		ret = (f_flags != O_RDWR) ? -EINVAL : bpf_prog_new_fd(raw);
 	else if (type == BPF_TYPE_MAP)
 		ret = bpf_map_new_fd(raw, f_flags);
 	else if (type == BPF_TYPE_LINK)