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Subject[PATCH v3 3/7] xfrm/compat: Attach xfrm dumps to 64=>32 bit translator
Date
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>
---
net/xfrm/xfrm_user.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c
index 3769227ed4e1..7fd7b16a8805 100644
--- 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;
}

--
2.28.0
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