From 26711a791effbea125fea4284f4d1c4fa8f7bc73 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Thu, 2 Feb 2012 17:33:59 -0800 Subject: [PATCH] userns: xt_owner: Add basic user namespace support. - Only allow adding matches from the initial user namespace - Add the appropriate conversion functions to handle matches against sockets in other user namespaces. Cc: Jan Engelhardt Cc: Patrick McHardy Cc: Pablo Neira Ayuso Acked-by: David S. Miller Acked-by: Serge Hallyn Signed-off-by: Eric W. Biederman --- init/Kconfig | 1 - net/netfilter/xt_owner.c | 30 ++++++++++++++++++++++++------ 2 files changed, 24 insertions(+), 7 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 40f50204dddb..76ffca9729b3 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -943,7 +943,6 @@ config UIDGID_CONVERTED # Networking depends on NET_9P = n - depends on NETFILTER_XT_MATCH_OWNER = n depends on AF_RXRPC = n depends on NET_KEY = n depends on DNS_RESOLVER = n diff --git a/net/netfilter/xt_owner.c b/net/netfilter/xt_owner.c index 772d7389b337..ca2e577ed8ac 100644 --- a/net/netfilter/xt_owner.c +++ b/net/netfilter/xt_owner.c @@ -17,6 +17,17 @@ #include #include +static int owner_check(const struct xt_mtchk_param *par) +{ + struct xt_owner_match_info *info = par->matchinfo; + + /* For now only allow adding matches from the initial user namespace */ + if ((info->match & (XT_OWNER_UID|XT_OWNER_GID)) && + (current_user_ns() != &init_user_ns)) + return -EINVAL; + return 0; +} + static bool owner_mt(const struct sk_buff *skb, struct xt_action_param *par) { @@ -37,17 +48,23 @@ owner_mt(const struct sk_buff *skb, struct xt_action_param *par) return ((info->match ^ info->invert) & (XT_OWNER_UID | XT_OWNER_GID)) == 0; - if (info->match & XT_OWNER_UID) - if ((filp->f_cred->fsuid >= info->uid_min && - filp->f_cred->fsuid <= info->uid_max) ^ + if (info->match & XT_OWNER_UID) { + kuid_t uid_min = make_kuid(&init_user_ns, info->uid_min); + kuid_t uid_max = make_kuid(&init_user_ns, info->uid_max); + if ((uid_gte(filp->f_cred->fsuid, uid_min) && + uid_lte(filp->f_cred->fsuid, uid_max)) ^ !(info->invert & XT_OWNER_UID)) return false; + } - if (info->match & XT_OWNER_GID) - if ((filp->f_cred->fsgid >= info->gid_min && - filp->f_cred->fsgid <= info->gid_max) ^ + if (info->match & XT_OWNER_GID) { + kgid_t gid_min = make_kgid(&init_user_ns, info->gid_min); + kgid_t gid_max = make_kgid(&init_user_ns, info->gid_max); + if ((gid_gte(filp->f_cred->fsgid, gid_min) && + gid_lte(filp->f_cred->fsgid, gid_max)) ^ !(info->invert & XT_OWNER_GID)) return false; + } return true; } @@ -56,6 +73,7 @@ static struct xt_match owner_mt_reg __read_mostly = { .name = "owner", .revision = 1, .family = NFPROTO_UNSPEC, + .checkentry = owner_check, .match = owner_mt, .matchsize = sizeof(struct xt_owner_match_info), .hooks = (1 << NF_INET_LOCAL_OUT) | -- 2.20.1