This patch implements xt_cgroup path match which matches cgroup2
membership of the associated socket. The match is recursive and
invertible.
For rationales on introducing another cgroup based match, please refer
to a preceding commit "sock, cgroup: add sock->sk_cgroup".
v3: Folded into xt_cgroup as a new revision interface as suggested by
Pablo.
v2: Included linux/limits.h from xt_cgroup2.h for PATH_MAX. Added
explicit alignment to the priv field. Both suggested by Jan.
Signed-off-by: Tejun Heo <t...@kernel.org>
Cc: Daniel Borkmann <dan...@iogearbox.net>
Cc: Daniel Wagner <daniel.wag...@bmw-carit.de>
CC: Neil Horman <nhor...@tuxdriver.com>
Cc: Jan Engelhardt <jeng...@inai.de>
Cc: Pablo Neira Ayuso <pa...@netfilter.org>
---
include/uapi/linux/netfilter/xt_cgroup.h | 13 ++++++
net/netfilter/xt_cgroup.c | 69 ++++++++++++++++++++++++++++++++
2 files changed, 82 insertions(+)
diff --git a/include/uapi/linux/netfilter/xt_cgroup.h
b/include/uapi/linux/netfilter/xt_cgroup.h
index 577c9e0..1e4b37b 100644
--- a/include/uapi/linux/netfilter/xt_cgroup.h
+++ b/include/uapi/linux/netfilter/xt_cgroup.h
@@ -2,10 +2,23 @@
#define _UAPI_XT_CGROUP_H
#include <linux/types.h>
+#include <linux/limits.h>
struct xt_cgroup_info_v0 {
__u32 id;
__u32 invert;
};
+struct xt_cgroup_info_v1 {
+ __u8 has_path;
+ __u8 has_classid;
+ __u8 invert_path;
+ __u8 invert_classid;
+ char path[PATH_MAX];
+ __u32 classid;
+
+ /* kernel internal data */
+ void *priv __attribute__((aligned(8)));
+};
+
#endif /* _UAPI_XT_CGROUP_H */
diff --git a/net/netfilter/xt_cgroup.c b/net/netfilter/xt_cgroup.c
index 1730025..a086a91 100644
--- a/net/netfilter/xt_cgroup.c
+++ b/net/netfilter/xt_cgroup.c
@@ -34,6 +34,37 @@ static int cgroup_mt_check_v0(const struct xt_mtchk_param
*par)
return 0;
}
+static int cgroup_mt_check_v1(const struct xt_mtchk_param *par)
+{
+ struct xt_cgroup_info_v1 *info = par->matchinfo;
+ struct cgroup *cgrp;
+
+ if ((info->invert_path & ~1) || (info->invert_classid & ~1))
+ return -EINVAL;
+
+ if (!info->has_path && !info->has_classid) {
+ pr_info("xt_cgroup: no path or classid specified\n");
+ return -EINVAL;
+ }
+
+ if (info->has_path && info->has_classid) {
+ pr_info("xt_cgroup: both path and classid specified\n");
+ return -EINVAL;
+ }
+
+ if (info->has_path) {
+ cgrp = cgroup_get_from_path(info->path);
+ if (IS_ERR(cgrp)) {
+ pr_info("xt_cgroup: invalid path, errno=%ld\n",
+ PTR_ERR(cgrp));
+ return -EINVAL;
+ }
+ info->priv = cgrp;
+ }
+
+ return 0;
+}
+
static bool
cgroup_mt_v0(const struct sk_buff *skb, struct xt_action_param *par)
{
@@ -46,6 +77,31 @@ cgroup_mt_v0(const struct sk_buff *skb, struct
xt_action_param *par)
info->invert;
}
+static bool cgroup_mt_v1(const struct sk_buff *skb, struct xt_action_param
*par)
+{
+ const struct xt_cgroup_info_v1 *info = par->matchinfo;
+ struct sock_cgroup_data *skcd = &skb->sk->sk_cgrp_data;
+ struct cgroup *ancestor = info->priv;
+
+ if (!skb->sk || !sk_fullsock(skb->sk))
+ return false;
+
+ if (ancestor)
+ return cgroup_is_descendant(sock_cgroup_ptr(skcd), ancestor) ^
+ info->invert_path;
+ else
+ return (info->classid == sock_cgroup_classid(skcd)) ^
+ info->invert_classid;
+}
+
+static void cgroup_mt_destroy_v1(const struct xt_mtdtor_param *par)
+{
+ struct xt_cgroup_info_v1 *info = par->matchinfo;
+
+ if (info->priv)
+ cgroup_put(info->priv);
+}
+
static struct xt_match cgroup_mt_reg[] __read_mostly = {
{
.name = "cgroup",
@@ -59,6 +115,19 @@ static struct xt_match cgroup_mt_reg[] __read_mostly = {
(1 << NF_INET_POST_ROUTING) |
(1 << NF_INET_LOCAL_IN),
},
+ {
+ .name = "cgroup",
+ .revision = 1,
+ .family = NFPROTO_UNSPEC,
+ .checkentry = cgroup_mt_check_v1,
+ .match = cgroup_mt_v1,
+ .matchsize = sizeof(struct xt_cgroup_info_v1),
+ .destroy = cgroup_mt_destroy_v1,
+ .me = THIS_MODULE,
+ .hooks = (1 << NF_INET_LOCAL_OUT) |
+ (1 << NF_INET_POST_ROUTING) |
+ (1 << NF_INET_LOCAL_IN),
+ },
};
static int __init cgroup_mt_init(void)
--
2.5.0
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