diff mbox

[4/7] netprio_cgroup: limit the maximum css->id to USHRT_MAX

Message ID 1447959171-20749-5-git-send-email-tj@kernel.org
State Changes Requested, archived
Delegated to: David Miller
Headers show

Commit Message

Tejun Heo Nov. 19, 2015, 6:52 p.m. UTC 
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 <tj@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Daniel Wagner <daniel.wagner@bmw-carit.de>
CC: Neil Horman <nhorman@tuxdriver.com>
---
 include/net/sock.h        | 10 +++++-----
 net/core/netprio_cgroup.c |  9 +++++++++
 2 files changed, 14 insertions(+), 5 deletions(-)

Comments

Daniel Wagner Nov. 20, 2015, 9:18 a.m. UTC | #1 
On 11/19/2015 07:52 PM, Tejun Heo wrote:
> 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 <tj@kernel.org>
> Cc: Daniel Borkmann <daniel@iogearbox.net>
> Cc: Daniel Wagner <daniel.wagner@bmw-carit.de>

Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
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diff mbox

Patch

diff --git a/include/net/sock.h b/include/net/sock.h
index bbf7c2c..b517351 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
@@ -423,9 +423,7 @@  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;
@@ -443,7 +441,9 @@  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;