From 5d359b97a59f27d4bace5a43695c1fed37e61bd9 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 22 Dec 2015 13:57:07 -0500 Subject: libxt_cgroup2: add support for cgroup2 path matching 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 Cc: Daniel Borkmann Cc: Jan Engelhardt Cc: Pablo Neira Ayuso Signed-off-by: Pablo Neira Ayuso --- extensions/libxt_cgroup.c | 86 +++++++++++++++++++++++++++++++++++++ extensions/libxt_cgroup.man | 33 ++++++++------ include/linux/netfilter/xt_cgroup.h | 13 ++++++ 3 files changed, 119 insertions(+), 13 deletions(-) diff --git a/extensions/libxt_cgroup.c b/extensions/libxt_cgroup.c index 64447f49..bea3c808 100644 --- 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 cgroup_opts_v0[] = { 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_option_call *cb) 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 *ip, const struct xt_entry_match *match) 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) diff --git a/extensions/libxt_cgroup.man b/extensions/libxt_cgroup.man index d0eb09b2..4d5d1d86 100644 --- 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. diff --git a/include/linux/netfilter/xt_cgroup.h b/include/linux/netfilter/xt_cgroup.h index 42b44a23..7fe61ed0 100644 --- a/include/linux/netfilter/xt_cgroup.h +++ b/include/linux/netfilter/xt_cgroup.h @@ -2,10 +2,23 @@ #define _XT_CGROUP_H #include +#include 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 */ -- cgit v1.2.3