From c53ed7423619b4e8108914a9f31b426dd58ad591 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 19 Nov 2013 15:19:31 +0100 Subject: genetlink: only pass array to genl_register_family_with_ops() As suggested by David Miller, make genl_register_family_with_ops() a macro and pass only the array, evaluating ARRAY_SIZE() in the macro, this is a little safer. The openvswitch has some indirection, assing ops/n_ops directly in that code. This might ultimately just assign the pointers in the family initializations, saving the struct genl_family_and_ops and code (once mcast groups are handled differently.) Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- fs/dlm/netlink.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'fs') diff --git a/fs/dlm/netlink.c b/fs/dlm/netlink.c index 60a327863b11..e7cfbaf8d0e2 100644 --- a/fs/dlm/netlink.c +++ b/fs/dlm/netlink.c @@ -74,14 +74,16 @@ static int user_cmd(struct sk_buff *skb, struct genl_info *info) return 0; } -static struct genl_ops dlm_nl_ops = { - .cmd = DLM_CMD_HELLO, - .doit = user_cmd, +static struct genl_ops dlm_nl_ops[] = { + { + .cmd = DLM_CMD_HELLO, + .doit = user_cmd, + }, }; int __init dlm_netlink_init(void) { - return genl_register_family_with_ops(&family, &dlm_nl_ops, 1); + return genl_register_family_with_ops(&family, dlm_nl_ops); } void dlm_netlink_exit(void) -- cgit v1.2.1 From 2ecf7536b2787580616d23b6507005d930975ca0 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 19 Nov 2013 15:19:33 +0100 Subject: 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 Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- fs/quota/netlink.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/quota/netlink.c b/fs/quota/netlink.c index 16e8abb7709b..aa22fe03b76c 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("a_genl_family) != 0) printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n"); + if (genl_register_mc_group("a_genl_family, "a_mcgrp)) + printk(KERN_ERR + "VFS: Failed to register quota mcast group.\n"); return 0; }; -- cgit v1.2.1 From 68eb55031da7c967d954e5f9415cd05f4abdb692 Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 19 Nov 2013 15:19:38 +0100 Subject: genetlink: pass family to functions using groups This doesn't really change anything, but prepares for the next patch that will change the APIs to pass the group ID within the family, rather than the global group ID. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- fs/quota/netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/quota/netlink.c b/fs/quota/netlink.c index aa22fe03b76c..a5b5eddf6603 100644 --- a/fs/quota/netlink.c +++ b/fs/quota/netlink.c @@ -88,7 +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_mcgrp.id, GFP_NOFS); + genlmsg_multicast("a_genl_family, skb, 0, quota_mcgrp.id, GFP_NOFS); return; attr_err_out: printk(KERN_ERR "VFS: Not enough space to compose quota message!\n"); -- cgit v1.2.1 From 2a94fe48f32ccf7321450a2cc07f2b724a444e5b Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Tue, 19 Nov 2013 15:19:39 +0100 Subject: genetlink: make multicast groups const, prevent abuse Register generic netlink multicast groups as an array with the family and give them contiguous group IDs. Then instead of passing the global group ID to the various functions that send messages, pass the ID relative to the family - for most families that's just 0 because the only have one group. This avoids the list_head and ID in each group, adding a new field for the mcast group ID offset to the family. At the same time, this allows us to prevent abusing groups again like the quota and dropmon code did, since we can now check that a family only uses a group it owns. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller --- fs/quota/netlink.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) (limited to 'fs') diff --git a/fs/quota/netlink.c b/fs/quota/netlink.c index a5b5eddf6603..72d29177998e 100644 --- a/fs/quota/netlink.c +++ b/fs/quota/netlink.c @@ -9,6 +9,10 @@ #include #include +static const struct genl_multicast_group quota_mcgrps[] = { + { .name = "events", }, +}; + /* Netlink family structure for quota */ static struct genl_family quota_genl_family = { /* @@ -22,10 +26,8 @@ static struct genl_family quota_genl_family = { .name = "VFS_DQUOT", .version = 1, .maxattr = QUOTA_NL_A_MAX, -}; - -static struct genl_multicast_group quota_mcgrp = { - .name = "events", + .mcgrps = quota_mcgrps, + .n_mcgrps = ARRAY_SIZE(quota_mcgrps), }; /** @@ -88,7 +90,7 @@ void quota_send_warning(struct kqid qid, dev_t dev, goto attr_err_out; genlmsg_end(skb, msg_head); - genlmsg_multicast("a_genl_family, skb, 0, quota_mcgrp.id, GFP_NOFS); + genlmsg_multicast("a_genl_family, skb, 0, 0, GFP_NOFS); return; attr_err_out: printk(KERN_ERR "VFS: Not enough space to compose quota message!\n"); @@ -102,9 +104,6 @@ static int __init quota_init(void) if (genl_register_family("a_genl_family) != 0) printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n"); - if (genl_register_mc_group("a_genl_family, "a_mcgrp)) - printk(KERN_ERR - "VFS: Failed to register quota mcast group.\n"); return 0; }; -- cgit v1.2.1