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Date: Tue, 09 Oct 2007 22:36:35 +0800
From: Herbert Xu <herbert@...dor.apana.org.au>
To: "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
Herbert Xu <herbert@...dor.apana.org.au>
Subject: [PATCH 5/7] [XFRM] user: Move attribute copying code into copy_to_user_state_extra
[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: Herbert Xu <herbert@...dor.apana.org.au>
---
net/xfrm/xfrm_user.c | 76 +++++++++++++++++++++++++++++++--------------------
1 files changed, 47 insertions(+), 29 deletions(-)
diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 52c7fce..2cbbe5e 100644
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -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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