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rtnetlink: enable alt_ifname for setlink/newlink
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buffer called "ifname" given in function rtnl_dev_get
is always valid when called by setlink/newlink,
but contains only empty string when IFLA_IFNAME is not given. So
IFLA_ALT_IFNAME is always ignored

This patch fixes rtnl_dev_get function with a remove of ifname argument,
and move ifname copy in do_setlink when required.

It extends feature of commit 76c9ac0,
"net: rtnetlink: add possibility to use alternative names as message
handle""

CC: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Florent Fourcot <florent.fourcot@wifirst.fr>
Signed-off-by: Brian Baboch <brian.baboch@wifirst.fr>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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Florent Fourcot authored and Paolo Abeni committed Apr 19, 2022
1 parent ef2a7c9 commit 5ea08b5
Showing 1 changed file with 29 additions and 40 deletions.
69 changes: 29 additions & 40 deletions net/core/rtnetlink.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2644,17 +2644,23 @@ static int do_set_proto_down(struct net_device *dev,
static int do_setlink(const struct sk_buff *skb,
struct net_device *dev, struct ifinfomsg *ifm,
struct netlink_ext_ack *extack,
struct nlattr **tb, char *ifname, int status)
struct nlattr **tb, int status)
{
const struct net_device_ops *ops = dev->netdev_ops;
char ifname[IFNAMSIZ];
int err;

err = validate_linkmsg(dev, tb, extack);
if (err < 0)
return err;

if (tb[IFLA_IFNAME])
nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
else
ifname[0] = '\0';

if (tb[IFLA_NET_NS_PID] || tb[IFLA_NET_NS_FD] || tb[IFLA_TARGET_NETNSID]) {
const char *pat = ifname && ifname[0] ? ifname : NULL;
const char *pat = ifname[0] ? ifname : NULL;
struct net *net;
int new_ifindex;

Expand Down Expand Up @@ -3010,21 +3016,16 @@ static int do_setlink(const struct sk_buff *skb,
}

static struct net_device *rtnl_dev_get(struct net *net,
struct nlattr *ifname_attr,
struct nlattr *altifname_attr,
char *ifname)
{
char buffer[ALTIFNAMSIZ];

if (!ifname) {
ifname = buffer;
if (ifname_attr)
nla_strscpy(ifname, ifname_attr, IFNAMSIZ);
else if (altifname_attr)
nla_strscpy(ifname, altifname_attr, ALTIFNAMSIZ);
else
return NULL;
}
struct nlattr *tb[])
{
char ifname[ALTIFNAMSIZ];

if (tb[IFLA_IFNAME])
nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
else if (tb[IFLA_ALT_IFNAME])
nla_strscpy(ifname, tb[IFLA_ALT_IFNAME], ALTIFNAMSIZ);
else
return NULL;

return __dev_get_by_name(net, ifname);
}
Expand All @@ -3037,7 +3038,6 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
struct net_device *dev;
int err;
struct nlattr *tb[IFLA_MAX+1];
char ifname[IFNAMSIZ];

err = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFLA_MAX,
ifla_policy, extack);
Expand All @@ -3048,17 +3048,12 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
if (err < 0)
goto errout;

if (tb[IFLA_IFNAME])
nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
else
ifname[0] = '\0';

err = -EINVAL;
ifm = nlmsg_data(nlh);
if (ifm->ifi_index > 0)
dev = __dev_get_by_index(net, ifm->ifi_index);
else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname);
dev = rtnl_dev_get(net, tb);
else
goto errout;

Expand All @@ -3067,7 +3062,7 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh,
goto errout;
}

err = do_setlink(skb, dev, ifm, extack, tb, ifname, 0);
err = do_setlink(skb, dev, ifm, extack, tb, 0);
errout:
return err;
}
Expand Down Expand Up @@ -3156,8 +3151,7 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh,
if (ifm->ifi_index > 0)
dev = __dev_get_by_index(tgt_net, ifm->ifi_index);
else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
dev = rtnl_dev_get(net, tb[IFLA_IFNAME],
tb[IFLA_ALT_IFNAME], NULL);
dev = rtnl_dev_get(net, tb);
else if (tb[IFLA_GROUP])
err = rtnl_group_dellink(tgt_net, nla_get_u32(tb[IFLA_GROUP]));
else
Expand Down Expand Up @@ -3299,7 +3293,7 @@ static int rtnl_group_changelink(const struct sk_buff *skb,

for_each_netdev_safe(net, dev, aux) {
if (dev->group == group) {
err = do_setlink(skb, dev, ifm, extack, tb, NULL, 0);
err = do_setlink(skb, dev, ifm, extack, tb, 0);
if (err < 0)
return err;
}
Expand Down Expand Up @@ -3341,18 +3335,13 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
if (err < 0)
return err;

if (tb[IFLA_IFNAME])
nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
else
ifname[0] = '\0';

ifm = nlmsg_data(nlh);
if (ifm->ifi_index > 0) {
link_specified = true;
dev = __dev_get_by_index(net, ifm->ifi_index);
} else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) {
link_specified = true;
dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname);
dev = rtnl_dev_get(net, tb);
} else {
link_specified = false;
dev = NULL;
Expand Down Expand Up @@ -3455,7 +3444,7 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
status |= DO_SETLINK_NOTIFY;
}

return do_setlink(skb, dev, ifm, extack, tb, ifname, status);
return do_setlink(skb, dev, ifm, extack, tb, status);
}

if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {
Expand Down Expand Up @@ -3492,7 +3481,9 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh,
if (!ops->alloc && !ops->setup)
return -EOPNOTSUPP;

if (!ifname[0]) {
if (tb[IFLA_IFNAME]) {
nla_strscpy(ifname, tb[IFLA_IFNAME], IFNAMSIZ);
} else {
snprintf(ifname, IFNAMSIZ, "%s%%d", ops->kind);
name_assign_type = NET_NAME_ENUM;
}
Expand Down Expand Up @@ -3664,8 +3655,7 @@ static int rtnl_getlink(struct sk_buff *skb, struct nlmsghdr *nlh,
if (ifm->ifi_index > 0)
dev = __dev_get_by_index(tgt_net, ifm->ifi_index);
else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
dev = rtnl_dev_get(tgt_net, tb[IFLA_IFNAME],
tb[IFLA_ALT_IFNAME], NULL);
dev = rtnl_dev_get(tgt_net, tb);
else
goto out;

Expand Down Expand Up @@ -3760,8 +3750,7 @@ static int rtnl_linkprop(int cmd, struct sk_buff *skb, struct nlmsghdr *nlh,
if (ifm->ifi_index > 0)
dev = __dev_get_by_index(net, ifm->ifi_index);
else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME])
dev = rtnl_dev_get(net, tb[IFLA_IFNAME],
tb[IFLA_ALT_IFNAME], NULL);
dev = rtnl_dev_get(net, tb);
else
return -EINVAL;

Expand Down

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