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authorJohannes Berg <johannes.berg@intel.com>2013-11-19 15:19:33 +0100
committerDavid S. Miller <davem@davemloft.net>2013-11-19 16:39:05 -0500
commit2ecf7536b2787580616d23b6507005d930975ca0 (patch)
tree050b07aaf96d86a83ed42c34511a3f28e1c0d1d4 /fs
parente5dcecba015f9774a402ba559b80b16999747e3b (diff)
quota/genetlink: use proper genetlink multicast APIs
The quota code is abusing the genetlink API and is using its family ID as the multicast group ID, which is invalid and may belong to somebody else (and likely will.) Make the quota code use the correct API, but since this is already used as-is by userspace, reserve a family ID for this code and also reserve that group ID to not break userspace assumptions. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'fs')
-rw-r--r--fs/quota/netlink.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/fs/quota/netlink.c b/fs/quota/netlink.c
index 16e8abb7709..aa22fe03b76 100644
--- a/fs/quota/netlink.c
+++ b/fs/quota/netlink.c
@@ -11,13 +11,23 @@
/* Netlink family structure for quota */
static struct genl_family quota_genl_family = {
- .id = GENL_ID_GENERATE,
+ /*
+ * Needed due to multicast group ID abuse - old code assumed
+ * the family ID was also a valid multicast group ID (which
+ * isn't true) and userspace might thus rely on it. Assign a
+ * static ID for this group to make dealing with that easier.
+ */
+ .id = GENL_ID_VFS_DQUOT,
.hdrsize = 0,
.name = "VFS_DQUOT",
.version = 1,
.maxattr = QUOTA_NL_A_MAX,
};
+static struct genl_multicast_group quota_mcgrp = {
+ .name = "events",
+};
+
/**
* quota_send_warning - Send warning to userspace about exceeded quota
* @type: The quota type: USRQQUOTA, GRPQUOTA,...
@@ -78,7 +88,7 @@ void quota_send_warning(struct kqid qid, dev_t dev,
goto attr_err_out;
genlmsg_end(skb, msg_head);
- genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
+ genlmsg_multicast(skb, 0, quota_mcgrp.id, GFP_NOFS);
return;
attr_err_out:
printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
@@ -92,6 +102,9 @@ static int __init quota_init(void)
if (genl_register_family(&quota_genl_family) != 0)
printk(KERN_ERR
"VFS: Failed to create quota netlink interface.\n");
+ if (genl_register_mc_group(&quota_genl_family, &quota_mcgrp))
+ printk(KERN_ERR
+ "VFS: Failed to register quota mcast group.\n");
return 0;
};