| From a669e48453c5666f1f2cf9c69506d945fbd77ecd Mon Sep 17 00:00:00 2001 |
| From: Hangbin Liu <liuhangbin@gmail.com> |
| Date: Wed, 11 Dec 2019 22:20:16 +0800 |
| Subject: [PATCH] ipv6/addrconf: only check invalid header values when |
| NETLINK_F_STRICT_CHK is set |
| |
| commit 2beb6d2901a3f73106485d560c49981144aeacb1 upstream. |
| |
| In commit 4b1373de73a3 ("net: ipv6: addr: perform strict checks also for |
| doit handlers") we add strict check for inet6_rtm_getaddr(). But we did |
| the invalid header values check before checking if NETLINK_F_STRICT_CHK |
| is set. This may break backwards compatibility if user already set the |
| ifm->ifa_prefixlen, ifm->ifa_flags, ifm->ifa_scope in their netlink code. |
| |
| I didn't move the nlmsg_len check because I thought it's a valid check. |
| |
| Reported-by: Jianlin Shi <jishi@redhat.com> |
| Fixes: 4b1373de73a3 ("net: ipv6: addr: perform strict checks also for doit handlers") |
| Signed-off-by: Hangbin Liu <liuhangbin@gmail.com> |
| Reviewed-by: David Ahern <dsahern@gmail.com> |
| Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c |
| index c94bc461e268..9f2c4bc260ef 100644 |
| --- a/net/ipv6/addrconf.c |
| +++ b/net/ipv6/addrconf.c |
| @@ -5229,16 +5229,16 @@ static int inet6_rtm_valid_getaddr_req(struct sk_buff *skb, |
| return -EINVAL; |
| } |
| |
| + if (!netlink_strict_get_check(skb)) |
| + return nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX, |
| + ifa_ipv6_policy, extack); |
| + |
| ifm = nlmsg_data(nlh); |
| if (ifm->ifa_prefixlen || ifm->ifa_flags || ifm->ifa_scope) { |
| NL_SET_ERR_MSG_MOD(extack, "Invalid values in header for get address request"); |
| return -EINVAL; |
| } |
| |
| - if (!netlink_strict_get_check(skb)) |
| - return nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX, |
| - ifa_ipv6_policy, extack); |
| - |
| err = nlmsg_parse_deprecated_strict(nlh, sizeof(*ifm), tb, IFA_MAX, |
| ifa_ipv6_policy, extack); |
| if (err) |
| -- |
| 2.7.4 |
| |
