This patch updates xt_cgroup so that it supports revision 1 interface
which includes cgroup2 path based matching.
v3: Folded into xt_cgroup as a new revision interface as suggested by
Pablo.
v2: cgroup2_match->userspacesize and ->save and man page updated as
per Jan.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Daniel Borkmann <dborkman@xxxxxxxxxx>
Cc: Jan Engelhardt <jengelh@xxxxxxx>
Cc: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
---
extensions/libxt_cgroup.c | 86 ++++++++++++++++++++++++++++++++++++
extensions/libxt_cgroup.man | 33 ++++++++-----
include/linux/netfilter/xt_cgroup.h | 13 +++++
3 files changed, 119 insertions(+), 13 deletions(-)
--- a/extensions/libxt_cgroup.c
+++ b/extensions/libxt_cgroup.c
@@ -4,6 +4,7 @@
enum {
O_CLASSID = 0,
+ O_PATH = 1,
};
static void cgroup_help_v0(void)
@@ -13,6 +14,14 @@ static void cgroup_help_v0(void)
"[!] --cgroup classid Match cgroup classid\n");
}
+static void cgroup_help_v1(void)
+{
+ printf(
+"cgroup match options:\n"
+"[!] --path path Recursively match path relative to cgroup2 root\n"
+"[!] --cgroup claasid Match cgroup classid, can't be used with --path\n");
+}
+
static const struct xt_option_entry cgroup_opts_v0[] = {
{
.name = "cgroup",
@@ -24,6 +33,24 @@ static const struct xt_option_entry cgro
XTOPT_TABLEEND,
};
+static const struct xt_option_entry cgroup_opts_v1[] = {
+ {
+ .name = "path",
+ .id = O_PATH,
+ .type = XTTYPE_STRING,
+ .flags = XTOPT_INVERT | XTOPT_PUT,
+ XTOPT_POINTER(struct xt_cgroup_info_v1, path)
+ },
+ {
+ .name = "cgroup",
+ .id = O_CLASSID,
+ .type = XTTYPE_UINT32,
+ .flags = XTOPT_INVERT | XTOPT_PUT,
+ XTOPT_POINTER(struct xt_cgroup_info_v1, classid)
+ },
+ XTOPT_TABLEEND,
+};
+
static void cgroup_parse_v0(struct xt_option_call *cb)
{
struct xt_cgroup_info_v0 *cgroupinfo = cb->data;
@@ -33,6 +60,26 @@ static void cgroup_parse_v0(struct xt_op
cgroupinfo->invert = true;
}
+static void cgroup_parse_v1(struct xt_option_call *cb)
+{
+ struct xt_cgroup_info_v1 *info = cb->data;
+
+ xtables_option_parse(cb);
+
+ switch (cb->entry->id) {
+ case O_PATH:
+ info->has_path = true;
+ if (cb->invert)
+ info->invert_path = true;
+ break;
+ case O_CLASSID:
+ info->has_classid = true;
+ if (cb->invert)
+ info->invert_classid = true;
+ break;
+ }
+}
+
static void
cgroup_print_v0(const void *ip, const struct xt_entry_match *match, int numeric)
{
@@ -48,6 +95,32 @@ static void cgroup_save_v0(const void *i
printf("%s --cgroup %u", info->invert ? " !" : "", info->id);
}
+static void
+cgroup_print_v1(const void *ip, const struct xt_entry_match *match, int numeric)
+{
+ const struct xt_cgroup_info_v1 *info = (void *)match->data;
+
+ printf(" cgroup");
+ if (info->has_path)
+ printf(" %s%s", info->invert_path ? "! ":"", info->path);
+ if (info->has_classid)
+ printf(" %s%u", info->invert_classid ? "! ":"", info->classid);
+}
+
+static void cgroup_save_v1(const void *ip, const struct xt_entry_match *match)
+{
+ const struct xt_cgroup_info_v1 *info = (void *)match->data;
+
+ if (info->has_path) {
+ printf("%s --path", info->invert_path ? " !" : "");
+ xtables_save_string(info->path);
+ }
+
+ if (info->has_classid)
+ printf("%s --cgroup %u", info->invert_classid ? " !" : "",
+ info->classid);
+}
+
static struct xtables_match cgroup_match[] = {
{
.family = NFPROTO_UNSPEC,
@@ -62,6 +135,19 @@ static struct xtables_match cgroup_match
.x6_parse = cgroup_parse_v0,
.x6_options = cgroup_opts_v0,
},
+ {
+ .family = NFPROTO_UNSPEC,
+ .revision = 1,
+ .name = "cgroup",
+ .version = XTABLES_VERSION,
+ .size = XT_ALIGN(sizeof(struct xt_cgroup_info_v1)),
+ .userspacesize = offsetof(struct xt_cgroup_info_v1, priv),
+ .help = cgroup_help_v1,
+ .print = cgroup_print_v1,
+ .save = cgroup_save_v1,
+ .x6_parse = cgroup_parse_v1,
+ .x6_options = cgroup_opts_v1,
+ },
};
void _init(void)
--- a/extensions/libxt_cgroup.man
+++ b/extensions/libxt_cgroup.man
@@ -1,23 +1,30 @@
.TP
-[\fB!\fP] \fB\-\-cgroup\fP \fIfwid\fP
-Match corresponding cgroup for this packet.
+[\fB!\fP] \fB\-\-path\fP \fIpath\fP
+Match cgroup2 membership.
-Can be used in the OUTPUT chain to assign particular firewall
-policies for aggregated task/jobs on the system. This allows
-for more fine-grained firewall policies that only match for a
-subset of the system's processes. fwid is the maker set through
-the net_cls cgroup's id.
+Each socket is associated with the v2 cgroup of the creating process.
+This matches packets coming from or going to all sockets in the
+sub-hierarchy of the specified path. The path should be relative to
+the root of the cgroup2 hierarchy.
+.TP
+[\fB!\fP] \fB\-\-cgroup\fP \fIclassid\fP
+Match cgroup net_cls classid.
-\fBIMPORTANT\fP: when being used in the INPUT chain, the cgroup
-matcher is currently only of limited functionality, meaning it
-will only match on packets that are processed for local sockets
-through early socket demuxing. Therefore, general usage on the
-INPUT chain is disadviced unless the implications are well
-understood.
+classid is the marker set through the cgroup net_cls controller. This
+option and \-\-path can't be used together.
.PP
Example:
.IP
+iptables \-A OUTPUT \-p tcp \-\-sport 80 \-m cgroup ! \-\-path service/http-server \-j DROP
+.IP
iptables \-A OUTPUT \-p tcp \-\-sport 80 \-m cgroup ! \-\-cgroup 1
\-j DROP
.PP
+\fBIMPORTANT\fP: when being used in the INPUT chain, the cgroup
+matcher is currently only of limited functionality, meaning it
+will only match on packets that are processed for local sockets
+through early socket demuxing. Therefore, general usage on the
+INPUT chain is not advised unless the implications are well
+understood.
+.PP
Available since Linux 3.14.
--- a/include/linux/netfilter/xt_cgroup.h
+++ b/include/linux/netfilter/xt_cgroup.h
@@ -2,10 +2,23 @@
#define _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 /* _XT_CGROUP_H */
--
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