[PATCH 4/8] netprio_cgroup: limit the maximum css->id to USHRT_MAX
From: Tejun Heo <hidden>
Date: 2015-12-07 22:39:19
Also in:
cgroups, lkml, netfilter-devel
Subsystem:
networking [general], networking [sockets], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Kuniyuki Iwashima, Willem de Bruijn, Linus Torvalds
netprio builds per-netdev contiguous priomap array which is indexed by css->id. The array is allocated using kzalloc() effectively limiting the maximum ID supported to some thousand range. This patch caps the maximum supported css->id to USHRT_MAX which should be way above what is actually useable. This allows reducing sock->sk_cgrp_prioidx to u16 from u32. The freed up part will be used to overload the cgroup related fields. sock->sk_cgrp_prioidx's position is swapped with sk_mark so that the two cgroup related fields are adjacent. Signed-off-by: Tejun Heo <redacted> Acked-by: Daniel Wagner <redacted> Cc: Daniel Borkmann <redacted> CC: Neil Horman <redacted> --- include/net/sock.h | 10 +++++----- net/core/netprio_cgroup.c | 9 +++++++++ 2 files changed, 14 insertions(+), 5 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 6f58b84..a95bcf7 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h@@ -288,7 +288,6 @@ struct cg_proto; * @sk_ack_backlog: current listen backlog * @sk_max_ack_backlog: listen backlog set in listen() * @sk_priority: %SO_PRIORITY setting - * @sk_cgrp_prioidx: socket group's priority map index * @sk_type: socket type (%SOCK_STREAM, etc) * @sk_protocol: which protocol this socket belongs in this network family * @sk_peer_pid: &struct pid for this socket's peer
@@ -309,6 +308,7 @@ struct cg_proto; * @sk_send_head: front of stuff to transmit * @sk_security: used by security modules * @sk_mark: generic packet mark + * @sk_cgrp_prioidx: socket group's priority map index * @sk_classid: this socket's cgroup classid * @sk_cgrp: this socket's cgroup-specific proto data * @sk_write_pending: a write to stream socket waits to start
@@ -425,9 +425,7 @@ struct sock { u32 sk_ack_backlog; u32 sk_max_ack_backlog; __u32 sk_priority; -#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO) - __u32 sk_cgrp_prioidx; -#endif + __u32 sk_mark; struct pid *sk_peer_pid; const struct cred *sk_peer_cred; long sk_rcvtimeo;
@@ -445,7 +443,9 @@ struct sock { #ifdef CONFIG_SECURITY void *sk_security; #endif - __u32 sk_mark; +#if IS_ENABLED(CONFIG_CGROUP_NET_PRIO) + u16 sk_cgrp_prioidx; +#endif #ifdef CONFIG_CGROUP_NET_CLASSID u32 sk_classid; #endif
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index cbd0a19..2b9159b 100644
--- a/net/core/netprio_cgroup.c
+++ b/net/core/netprio_cgroup.c@@ -27,6 +27,12 @@ #include <linux/fdtable.h> +/* + * netprio allocates per-net_device priomap array which is indexed by + * css->id. Limiting css ID to 16bits doesn't lose anything. + */ +#define NETPRIO_ID_MAX USHRT_MAX + #define PRIOMAP_MIN_SZ 128 /*
@@ -144,6 +150,9 @@ static int cgrp_css_online(struct cgroup_subsys_state *css) struct net_device *dev; int ret = 0; + if (css->id > NETPRIO_ID_MAX) + return -ENOSPC; + if (!parent_css) return 0;
--
2.5.0