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authorTejun Heo <tj@kernel.org>2015-12-07 17:38:51 -0500
committerDavid S. Miller <davem@davemloft.net>2015-12-08 22:02:33 -0500
commit297dbde19cf6a0ccb6fd4396c6220a5912ed61e8 (patch)
treed1b65de60b8d8adfd2f84542cd59d9ed61f12c6b /net/core/netprio_cgroup.c
parentbc9b145a092aca91a7f6ef40cdb3628b6ada7ec9 (diff)
downloadlinux-297dbde19cf6a0ccb6fd4396c6220a5912ed61e8.tar.gz
netprio_cgroup: limit the maximum css->id to USHRT_MAX
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>
Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Cc: Daniel Borkmann <daniel@iogearbox.net>
CC: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/netprio_cgroup.c')
-rw-r--r--net/core/netprio_cgroup.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/net/core/netprio_cgroup.c b/net/core/netprio_cgroup.c
index cbd0a199bf52..2b9159b7a28a 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;