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Commit 49b31e57 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by David S. Miller
Browse files

filter: refactor common filter attach code into __sk_attach_prog 



Both sk_attach_filter() and sk_attach_bpf() are setting up sk_filter,
charging skmem and attaching it to the socket after we got the eBPF
prog up and ready. Lets refactor that into a common helper.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 70c836a4

net/core/filter.c

+33 −38
Original line number Diff line number Diff line
@@ -1019,6 +1019,32 @@ void bpf_prog_destroy(struct bpf_prog *fp) 
}

EXPORT_SYMBOL_GPL(bpf_prog_destroy);



static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk)

{

	struct sk_filter *fp, *old_fp;



	fp = kmalloc(sizeof(*fp), GFP_KERNEL);

	if (!fp)

		return -ENOMEM;



	fp->prog = prog;

	atomic_set(&fp->refcnt, 0);



	if (!sk_filter_charge(sk, fp)) {

		kfree(fp);

		return -ENOMEM;

	}



	old_fp = rcu_dereference_protected(sk->sk_filter,

					   sock_owned_by_user(sk));

	rcu_assign_pointer(sk->sk_filter, fp);



	if (old_fp)

		sk_filter_uncharge(sk, old_fp);



	return 0;

}



/**

 *	sk_attach_filter - attach a socket filter

 *	@fprog: the filter program
@@ -1031,7 +1057,6 @@ EXPORT_SYMBOL_GPL(bpf_prog_destroy); 
 */

int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk)

{

	struct sk_filter *fp, *old_fp;

	unsigned int fsize = bpf_classic_proglen(fprog);

	unsigned int bpf_fsize = bpf_prog_size(fprog->len);

	struct bpf_prog *prog;
@@ -1068,35 +1093,20 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) 
	if (IS_ERR(prog))

		return PTR_ERR(prog);



	fp = kmalloc(sizeof(*fp), GFP_KERNEL);

	if (!fp) {

	err = __sk_attach_prog(prog, sk);

	if (err < 0) {

		__bpf_prog_release(prog);

		return -ENOMEM;

	}

	fp->prog = prog;



	atomic_set(&fp->refcnt, 0);



	if (!sk_filter_charge(sk, fp)) {

		__sk_filter_release(fp);

		return -ENOMEM;

		return err;

	}



	old_fp = rcu_dereference_protected(sk->sk_filter,

					   sock_owned_by_user(sk));

	rcu_assign_pointer(sk->sk_filter, fp);



	if (old_fp)

		sk_filter_uncharge(sk, old_fp);



	return 0;

}

EXPORT_SYMBOL_GPL(sk_attach_filter);



int sk_attach_bpf(u32 ufd, struct sock *sk)

{

	struct sk_filter *fp, *old_fp;

	struct bpf_prog *prog;

	int err;



	if (sock_flag(sk, SOCK_FILTER_LOCKED))

		return -EPERM;
@@ -1110,27 +1120,12 @@ int sk_attach_bpf(u32 ufd, struct sock *sk) 
		return -EINVAL;

	}



	fp = kmalloc(sizeof(*fp), GFP_KERNEL);

	if (!fp) {

	err = __sk_attach_prog(prog, sk);

	if (err < 0) {

		bpf_prog_put(prog);

		return -ENOMEM;

	}



	fp->prog = prog;

	atomic_set(&fp->refcnt, 0);



	if (!sk_filter_charge(sk, fp)) {

		__sk_filter_release(fp);

		return -ENOMEM;

		return err;

	}



	old_fp = rcu_dereference_protected(sk->sk_filter,

					   sock_owned_by_user(sk));

	rcu_assign_pointer(sk->sk_filter, fp);



	if (old_fp)

		sk_filter_uncharge(sk, old_fp);



	return 0;

}