Commit 68325d3b authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller
Browse files

[XFRM] user: Move attribute copying code into copy_to_user_state_extra 



Here's a good example of code duplication leading to code rot.  The
notification patch did its own netlink message creation for xfrm states.
It duplicated code that was already in dump_one_state.  Guess what, the
next time (and the time after) when someone updated dump_one_state the
notification path got zilch.

This patch moves that code from dump_one_state to copy_to_user_state_extra
and uses it in xfrm_notify_sa too.  Unfortunately whoever updates this
still needs to update xfrm_sa_len since the notification path wants to
know the exact size for allocation.

At least I've added a comment saying so and if someone still forgest, we'll
have a WARN_ON telling us so.

I also changed the security size calculation to use xfrm_user_sec_ctx since
that's what we actually put into the skb.  However it makes no practical
difference since it has the same size as xfrm_sec_ctx.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 658b219e

net/xfrm/xfrm_user.c

+47 −29
Original line number Diff line number Diff line
@@ -483,9 +483,9 @@ struct xfrm_dump_info { 


static int copy_sec_ctx(struct xfrm_sec_ctx *s, struct sk_buff *skb)

{

	int ctx_size = sizeof(struct xfrm_sec_ctx) + s->ctx_len;

	struct xfrm_user_sec_ctx *uctx;

	struct nlattr *attr;

	int ctx_size = sizeof(*uctx) + s->ctx_len;



	attr = nla_reserve(skb, XFRMA_SEC_CTX, ctx_size);

	if (attr == NULL)
@@ -502,23 +502,11 @@ static int copy_sec_ctx(struct xfrm_sec_ctx *s, struct sk_buff *skb) 
	return 0;

}



static int dump_one_state(struct xfrm_state *x, int count, void *ptr)

/* Don't change this without updating xfrm_sa_len! */

static int copy_to_user_state_extra(struct xfrm_state *x,

				    struct xfrm_usersa_info *p,

				    struct sk_buff *skb)

{

	struct xfrm_dump_info *sp = ptr;

	struct sk_buff *in_skb = sp->in_skb;

	struct sk_buff *skb = sp->out_skb;

	struct xfrm_usersa_info *p;

	struct nlmsghdr *nlh;



	if (sp->this_idx < sp->start_idx)

		goto out;



	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, sp->nlmsg_seq,

			XFRM_MSG_NEWSA, sizeof(*p), sp->nlmsg_flags);

	if (nlh == NULL)

		return -EMSGSIZE;



	p = nlmsg_data(nlh);

	copy_to_user_state(x, p);



	if (x->aalg)
@@ -540,6 +528,35 @@ static int dump_one_state(struct xfrm_state *x, int count, void *ptr) 
	if (x->lastused)

		NLA_PUT_U64(skb, XFRMA_LASTUSED, x->lastused);



	return 0;



nla_put_failure:

	return -EMSGSIZE;

}



static int dump_one_state(struct xfrm_state *x, int count, void *ptr)

{

	struct xfrm_dump_info *sp = ptr;

	struct sk_buff *in_skb = sp->in_skb;

	struct sk_buff *skb = sp->out_skb;

	struct xfrm_usersa_info *p;

	struct nlmsghdr *nlh;

	int err;



	if (sp->this_idx < sp->start_idx)

		goto out;



	nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, sp->nlmsg_seq,

			XFRM_MSG_NEWSA, sizeof(*p), sp->nlmsg_flags);

	if (nlh == NULL)

		return -EMSGSIZE;



	p = nlmsg_data(nlh);



	err = copy_to_user_state_extra(x, p, skb);

	if (err)

		goto nla_put_failure;



	nlmsg_end(skb, nlh);

out:

	sp->this_idx++;
@@ -547,7 +564,7 @@ out: 


nla_put_failure:

	nlmsg_cancel(skb, nlh);

	return -EMSGSIZE;

	return err;

}



static int xfrm_dump_sa(struct sk_buff *skb, struct netlink_callback *cb)
@@ -1973,6 +1990,14 @@ static inline size_t xfrm_sa_len(struct xfrm_state *x) 
		l += nla_total_size(sizeof(*x->calg));

	if (x->encap)

		l += nla_total_size(sizeof(*x->encap));

	if (x->security)

		l += nla_total_size(sizeof(struct xfrm_user_sec_ctx) +

				    x->security->ctx_len);

	if (x->coaddr)

		l += nla_total_size(sizeof(*x->coaddr));



	/* Must count this as this may become non-zero behind our back. */

	l += nla_total_size(sizeof(x->lastused));



	return l;

}
@@ -2018,23 +2043,16 @@ static int xfrm_notify_sa(struct xfrm_state *x, struct km_event *c) 
		p = nla_data(attr);

	}



	copy_to_user_state(x, p);



	if (x->aalg)

		NLA_PUT(skb, XFRMA_ALG_AUTH, alg_len(x->aalg), x->aalg);

	if (x->ealg)

		NLA_PUT(skb, XFRMA_ALG_CRYPT, alg_len(x->ealg), x->ealg);

	if (x->calg)

		NLA_PUT(skb, XFRMA_ALG_COMP, sizeof(*(x->calg)), x->calg);



	if (x->encap)

		NLA_PUT(skb, XFRMA_ENCAP, sizeof(*x->encap), x->encap);

	if (copy_to_user_state_extra(x, p, skb))

		goto nla_put_failure;



	nlmsg_end(skb, nlh);



	return nlmsg_multicast(xfrm_nl, skb, 0, XFRMNLGRP_SA, GFP_ATOMIC);



nla_put_failure:

	/* Somebody screwed up with xfrm_sa_len! */

	WARN_ON(1);

	kfree_skb(skb);

	return -1;

}

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