Commit e7d85427 authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Daniel Borkmann
Browse files

bpf: Validate BPF object in BPF_OBJ_PIN before calling LSM 



Do a sanity check whether provided file-to-be-pinned is actually a BPF
object (prog, map, btf) before calling security_path_mknod LSM hook. If
it's not, LSM hook doesn't have to be triggered, as the operation has no
chance of succeeding anyways.

Suggested-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/bpf/20230522232917.2454595-2-andrii@kernel.org
parent f46392ee

kernel/bpf/inode.c

+5 −6
Original line number Diff line number Diff line
@@ -448,18 +448,17 @@ static int bpf_obj_do_pin(const char __user *pathname, void *raw, 
	if (IS_ERR(dentry))

		return PTR_ERR(dentry);



	mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());



	ret = security_path_mknod(&path, dentry, mode, 0);

	if (ret)

		goto out;



	dir = d_inode(path.dentry);

	if (dir->i_op != &bpf_dir_iops) {

		ret = -EPERM;

		goto out;

	}



	mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());

	ret = security_path_mknod(&path, dentry, mode, 0);

	if (ret)

		goto out;



	switch (type) {

	case BPF_TYPE_PROG:

		ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw);