From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
- 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@xxxxxxxxxx>
Cc: Patrick McHardy <kaber@xxxxxxxxx>
Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Acked-by: Serge Hallyn <serge.hallyn@xxxxxxxxxxxxx>
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
---
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 40f5020..76ffca9 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 772d738..ca2e577 100644
--- a/net/netfilter/xt_owner.c
+++ b/net/netfilter/xt_owner.c
@@ -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) |
--
1.7.5.4
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