xfrm/compat: Attach xfrm dumps to 64=>32 bit translator

Currently nlmsg_unicast() is used by functions that dump structures that
can be different in size for compat tasks, see dump_one_state() and
dump_one_policy().

The following nlmsg_unicast() users exist today in xfrm:

         Function                          |    Message can be different
                                           |       in size on compat
-------------------------------------------|------------------------------
    xfrm_get_spdinfo()                     |               N
    xfrm_get_sadinfo()                     |               N
    xfrm_get_sa()                          |               Y
    xfrm_alloc_userspi()                   |               Y
    xfrm_get_policy()                      |               Y
    xfrm_get_ae()                          |               N

Besides, dump_one_state() and dump_one_policy() can be used by filtered
netlink dump for XFRM_MSG_GETSA, XFRM_MSG_GETPOLICY.

Just as for xfrm multicast, allocate frag_list for compat skb journey
down to recvmsg() which will give user the desired skb according to
syscall bitness.

Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 3769227..7fd7b16 100644 (file)
--- a/net/xfrm/xfrm_user.c
+++ b/net/xfrm/xfrm_user.c
@@ -975,6 +975,7 @@ 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_translator *xtr;
        struct xfrm_usersa_info *p;
        struct nlmsghdr *nlh;
        int err;
@@ -992,6 +993,18 @@ static int dump_one_state(struct xfrm_state *x, int count, void *ptr)
                return err;
        }
        nlmsg_end(skb, nlh);
+
+       xtr = xfrm_get_translator();
+       if (xtr) {
+               err = xtr->alloc_compat(skb, nlh);
+
+               xfrm_put_translator(xtr);
+               if (err) {
+                       nlmsg_cancel(skb, nlh);
+                       return err;
+               }
+       }
+
        return 0;
 }
 
@@ -1320,6 +1333,7 @@ static int xfrm_alloc_userspi(struct sk_buff *skb, struct nlmsghdr *nlh,
        struct net *net = sock_net(skb->sk);
        struct xfrm_state *x;
        struct xfrm_userspi_info *p;
+       struct xfrm_translator *xtr;
        struct sk_buff *resp_skb;
        xfrm_address_t *daddr;
        int family;
@@ -1370,6 +1384,17 @@ static int xfrm_alloc_userspi(struct sk_buff *skb, struct nlmsghdr *nlh,
                goto out;
        }
 
+       xtr = xfrm_get_translator();
+       if (xtr) {
+               err = xtr->alloc_compat(skb, nlmsg_hdr(skb));
+
+               xfrm_put_translator(xtr);
+               if (err) {
+                       kfree_skb(resp_skb);
+                       goto out;
+               }
+       }
+
        err = nlmsg_unicast(net->xfrm.nlsk, resp_skb, NETLINK_CB(skb).portid);
 
 out:
@@ -1776,6 +1801,7 @@ static int dump_one_policy(struct xfrm_policy *xp, int dir, int count, void *ptr
        struct xfrm_userpolicy_info *p;
        struct sk_buff *in_skb = sp->in_skb;
        struct sk_buff *skb = sp->out_skb;
+       struct xfrm_translator *xtr;
        struct nlmsghdr *nlh;
        int err;
 
@@ -1800,6 +1826,18 @@ static int dump_one_policy(struct xfrm_policy *xp, int dir, int count, void *ptr
                return err;
        }
        nlmsg_end(skb, nlh);
+
+       xtr = xfrm_get_translator();
+       if (xtr) {
+               err = xtr->alloc_compat(skb, nlh);
+
+               xfrm_put_translator(xtr);
+               if (err) {
+                       nlmsg_cancel(skb, nlh);
+                       return err;
+               }
+       }
+
        return 0;
 }