Commit 26711a79 authored by Eric W. Biederman's avatar Eric W. Biederman

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 <jengelh@medozas.de>
Cc: Patrick McHardy <kaber@trash.net>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: default avatarEric W. Biederman <ebiederm@xmission.com>
parent da742808
......@@ -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
......
......@@ -17,6 +17,17 @@
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_owner.h>
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) |
......
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