From ef2a7c9065cea4e3fbc0390e82d05141abbccd7f Mon Sep 17 00:00:00 2001 From: Florent Fourcot Date: Fri, 15 Apr 2022 18:53:27 +0200 Subject: rtnetlink: return ENODEV when ifname does not exist and group is given When the interface does not exist, and a group is given, the given parameters are being set to all interfaces of the given group. The given IFNAME/ALT_IF_NAME are being ignored in that case. That can be dangerous since a typo (or a deleted interface) can produce weird side effects for caller: Case 1: IFLA_IFNAME=valid_interface IFLA_GROUP=1 MTU=1234 Case 1 will update MTU and group of the given interface "valid_interface". Case 2: IFLA_IFNAME=doesnotexist IFLA_GROUP=1 MTU=1234 Case 2 will update MTU of all interfaces in group 1. IFLA_IFNAME is ignored in this case This behaviour is not consistent and dangerous. In order to fix this issue, we now return ENODEV when the given IFNAME does not exist. Signed-off-by: Florent Fourcot Signed-off-by: Brian Baboch Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni --- net/core/rtnetlink.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 8bf770a7261e..2f538ab512d0 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3326,6 +3326,7 @@ static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, struct ifinfomsg *ifm; char ifname[IFNAMSIZ]; struct nlattr **data; + bool link_specified; int err; #ifdef CONFIG_MODULES @@ -3346,12 +3347,16 @@ replay: ifname[0] = '\0'; ifm = nlmsg_data(nlh); - if (ifm->ifi_index > 0) + 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]) + } else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) { + link_specified = true; dev = rtnl_dev_get(net, NULL, tb[IFLA_ALT_IFNAME], ifname); - else + } else { + link_specified = false; dev = NULL; + } master_dev = NULL; m_ops = NULL; @@ -3454,7 +3459,12 @@ replay: } if (!(nlh->nlmsg_flags & NLM_F_CREATE)) { - if (ifm->ifi_index == 0 && tb[IFLA_GROUP]) + /* No dev found and NLM_F_CREATE not set. Requested dev does not exist, + * or it's for a group + */ + if (link_specified) + return -ENODEV; + if (tb[IFLA_GROUP]) return rtnl_group_changelink(skb, net, nla_get_u32(tb[IFLA_GROUP]), ifm, extack, tb); -- cgit v1.2.3 From 5ea08b5286f66ee5ac0150668c92d1718e83e1ad Mon Sep 17 00:00:00 2001 From: Florent Fourcot Date: Fri, 15 Apr 2022 18:53:28 +0200 Subject: rtnetlink: enable alt_ifname for setlink/newlink 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 76c9ac0ee878, "net: rtnetlink: add possibility to use alternative names as message handle"" CC: Jiri Pirko Signed-off-by: Florent Fourcot Signed-off-by: Brian Baboch Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni --- net/core/rtnetlink.c | 69 ++++++++++++++++++++++------------------------------ 1 file changed, 29 insertions(+), 40 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 2f538ab512d0..5899b1d2de14 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -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; @@ -3010,21 +3016,16 @@ errout: } 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); } @@ -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); @@ -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; @@ -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; } @@ -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 @@ -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; } @@ -3341,18 +3335,13 @@ replay: 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; @@ -3455,7 +3444,7 @@ replay: 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)) { @@ -3492,7 +3481,9 @@ replay: 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; } @@ -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; @@ -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; -- cgit v1.2.3 From dee04163e9f2feabb77615c630a1e31a91cc4449 Mon Sep 17 00:00:00 2001 From: Florent Fourcot Date: Fri, 15 Apr 2022 18:53:29 +0200 Subject: rtnetlink: return ENODEV when IFLA_ALT_IFNAME is used in dellink If IFLA_ALT_IFNAME is set and given interface is not found, we should return ENODEV and be consistent with IFLA_IFNAME behaviour This commit extends feature of commit 76c9ac0ee878, "net: rtnetlink: add possibility to use alternative names as message handle" CC: Jiri Pirko Signed-off-by: Florent Fourcot Signed-off-by: Brian Baboch Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni --- net/core/rtnetlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 5899b1d2de14..73f2cbc440c9 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3158,7 +3158,7 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, goto out; if (!dev) { - if (tb[IFLA_IFNAME] || ifm->ifi_index > 0) + if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME] || ifm->ifi_index > 0) err = -ENODEV; goto out; -- cgit v1.2.3 From b6177d3240a4f58fe547891010ad77a45bc1c9ab Mon Sep 17 00:00:00 2001 From: Florent Fourcot Date: Fri, 15 Apr 2022 18:53:30 +0200 Subject: rtnetlink: return EINVAL when request cannot succeed A request without interface name/interface index/interface group cannot work. We should return EINVAL Signed-off-by: Florent Fourcot Signed-off-by: Brian Baboch Reviewed-by: Jakub Kicinski Signed-off-by: Paolo Abeni --- net/core/rtnetlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 73f2cbc440c9..b943336908a7 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3457,7 +3457,7 @@ replay: return rtnl_group_changelink(skb, net, nla_get_u32(tb[IFLA_GROUP]), ifm, extack, tb); - return -ENODEV; + return -EINVAL; } if (tb[IFLA_MAP] || tb[IFLA_PROTINFO]) -- cgit v1.2.3