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Groups > linux.kernel > #1235109
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 3.10 53/56] sctp: fix race on protocol/netns initialization |
| Date | 2015-09-29 16:00 +0200 |
| Message-ID | <qe3BO-8he-63@gated-at.bofh.it> (permalink) |
| References | <qe3s5-85D-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
3.10-stable review patch. If anyone has any objections, please let me know.
------------------
From: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
[ Upstream commit 8e2d61e0aed2b7c4ecb35844fe07e0b2b762dee4 ]
Consider sctp module is unloaded and is being requested because an user
is creating a sctp socket.
During initialization, sctp will add the new protocol type and then
initialize pernet subsys:
status = sctp_v4_protosw_init();
if (status)
goto err_protosw_init;
status = sctp_v6_protosw_init();
if (status)
goto err_v6_protosw_init;
status = register_pernet_subsys(&sctp_net_ops);
The problem is that after those calls to sctp_v{4,6}_protosw_init(), it
is possible for userspace to create SCTP sockets like if the module is
already fully loaded. If that happens, one of the possible effects is
that we will have readers for net->sctp.local_addr_list list earlier
than expected and sctp_net_init() does not take precautions while
dealing with that list, leading to a potential panic but not limited to
that, as sctp_sock_init() will copy a bunch of blank/partially
initialized values from net->sctp.
The race happens like this:
CPU 0 | CPU 1
socket() |
__sock_create | socket()
inet_create | __sock_create
list_for_each_entry_rcu( |
answer, &inetsw[sock->type], |
list) { | inet_create
/* no hits */ |
if (unlikely(err)) { |
... |
request_module() |
/* socket creation is blocked |
* the module is fully loaded |
*/ |
sctp_init |
sctp_v4_protosw_init |
inet_register_protosw |
list_add_rcu(&p->list, |
last_perm); |
| list_for_each_entry_rcu(
| answer, &inetsw[sock->type],
sctp_v6_protosw_init | list) {
| /* hit, so assumes protocol
| * is already loaded
| */
| /* socket creation continues
| * before netns is initialized
| */
register_pernet_subsys |
Simply inverting the initialization order between
register_pernet_subsys() and sctp_v4_protosw_init() is not possible
because register_pernet_subsys() will create a control sctp socket, so
the protocol must be already visible by then. Deferring the socket
creation to a work-queue is not good specially because we loose the
ability to handle its errors.
So, as suggested by Vlad, the fix is to split netns initialization in
two moments: defaults and control socket, so that the defaults are
already loaded by when we register the protocol, while control socket
initialization is kept at the same moment it is today.
Fixes: 4db67e808640 ("sctp: Make the address lists per network namespace")
Signed-off-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/sctp/protocol.c | 64 +++++++++++++++++++++++++++++++++-------------------
1 file changed, 41 insertions(+), 23 deletions(-)
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -1170,7 +1170,7 @@ static void sctp_v4_del_protocol(void)
unregister_inetaddr_notifier(&sctp_inetaddr_notifier);
}
-static int __net_init sctp_net_init(struct net *net)
+static int __net_init sctp_defaults_init(struct net *net)
{
int status;
@@ -1263,12 +1263,6 @@ static int __net_init sctp_net_init(stru
sctp_dbg_objcnt_init(net);
- /* Initialize the control inode/socket for handling OOTB packets. */
- if ((status = sctp_ctl_sock_init(net))) {
- pr_err("Failed to initialize the SCTP control sock\n");
- goto err_ctl_sock_init;
- }
-
/* Initialize the local address list. */
INIT_LIST_HEAD(&net->sctp.local_addr_list);
spin_lock_init(&net->sctp.local_addr_lock);
@@ -1284,9 +1278,6 @@ static int __net_init sctp_net_init(stru
return 0;
-err_ctl_sock_init:
- sctp_dbg_objcnt_exit(net);
- sctp_proc_exit(net);
err_init_proc:
cleanup_sctp_mibs(net);
err_init_mibs:
@@ -1295,15 +1286,12 @@ err_sysctl_register:
return status;
}
-static void __net_exit sctp_net_exit(struct net *net)
+static void __net_exit sctp_defaults_exit(struct net *net)
{
/* Free the local address list */
sctp_free_addr_wq(net);
sctp_free_local_addr_list(net);
- /* Free the control endpoint. */
- inet_ctl_sock_destroy(net->sctp.ctl_sock);
-
sctp_dbg_objcnt_exit(net);
sctp_proc_exit(net);
@@ -1311,9 +1299,32 @@ static void __net_exit sctp_net_exit(str
sctp_sysctl_net_unregister(net);
}
-static struct pernet_operations sctp_net_ops = {
- .init = sctp_net_init,
- .exit = sctp_net_exit,
+static struct pernet_operations sctp_defaults_ops = {
+ .init = sctp_defaults_init,
+ .exit = sctp_defaults_exit,
+};
+
+static int __net_init sctp_ctrlsock_init(struct net *net)
+{
+ int status;
+
+ /* Initialize the control inode/socket for handling OOTB packets. */
+ status = sctp_ctl_sock_init(net);
+ if (status)
+ pr_err("Failed to initialize the SCTP control sock\n");
+
+ return status;
+}
+
+static void __net_init sctp_ctrlsock_exit(struct net *net)
+{
+ /* Free the control endpoint. */
+ inet_ctl_sock_destroy(net->sctp.ctl_sock);
+}
+
+static struct pernet_operations sctp_ctrlsock_ops = {
+ .init = sctp_ctrlsock_init,
+ .exit = sctp_ctrlsock_exit,
};
/* Initialize the universe into something sensible. */
@@ -1448,8 +1459,11 @@ SCTP_STATIC __init int sctp_init(void)
sctp_v4_pf_init();
sctp_v6_pf_init();
- status = sctp_v4_protosw_init();
+ status = register_pernet_subsys(&sctp_defaults_ops);
+ if (status)
+ goto err_register_defaults;
+ status = sctp_v4_protosw_init();
if (status)
goto err_protosw_init;
@@ -1457,9 +1471,9 @@ SCTP_STATIC __init int sctp_init(void)
if (status)
goto err_v6_protosw_init;
- status = register_pernet_subsys(&sctp_net_ops);
+ status = register_pernet_subsys(&sctp_ctrlsock_ops);
if (status)
- goto err_register_pernet_subsys;
+ goto err_register_ctrlsock;
status = sctp_v4_add_protocol();
if (status)
@@ -1476,12 +1490,14 @@ out:
err_v6_add_protocol:
sctp_v4_del_protocol();
err_add_protocol:
- unregister_pernet_subsys(&sctp_net_ops);
-err_register_pernet_subsys:
+ unregister_pernet_subsys(&sctp_ctrlsock_ops);
+err_register_ctrlsock:
sctp_v6_protosw_exit();
err_v6_protosw_init:
sctp_v4_protosw_exit();
err_protosw_init:
+ unregister_pernet_subsys(&sctp_defaults_ops);
+err_register_defaults:
sctp_v4_pf_exit();
sctp_v6_pf_exit();
sctp_sysctl_unregister();
@@ -1514,12 +1530,14 @@ SCTP_STATIC __exit void sctp_exit(void)
sctp_v6_del_protocol();
sctp_v4_del_protocol();
- unregister_pernet_subsys(&sctp_net_ops);
+ unregister_pernet_subsys(&sctp_ctrlsock_ops);
/* Free protosw registrations */
sctp_v6_protosw_exit();
sctp_v4_protosw_exit();
+ unregister_pernet_subsys(&sctp_defaults_ops);
+
/* Unregister with socket layer. */
sctp_v6_pf_exit();
sctp_v4_pf_exit();
--
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[PATCH 3.10 00/56] 3.10.90-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
[PATCH 3.10 01/56] unshare: Unsharing a thread does not require unsharing a vm Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
[PATCH 3.10 04/56] mac80211: enable assoc check for mesh interfaces Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
[PATCH 3.10 02/56] rtlwifi: rtl8192cu: Add new device ID Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
[PATCH 3.10 17/56] NFS: nfs_set_pgio_error sometimes misses errors Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
[PATCH 3.10 25/56] IB/uverbs: reject invalid or unknown opcodes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 15:50 +0200
[PATCH 3.10 40/56] net: Fix skb csum races when peeking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 43/56] isdn/gigaset: reset tty->receive_room when attaching ser_gigaset Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 55/56] vfs: Remove incorrect debugging WARN in prepend_path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 29/56] stmmac: fix check for phydev being open Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
Re: [PATCH 3.10 29/56] stmmac: fix check for phydev being open Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2015-09-30 13:30 +0200
[PATCH 3.10 49/56] ip6_gre: release cached dst on tunnel removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 27/56] IB/mlx4: Forbid using sysfs to change RoCE pkeys Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 31/56] sctp: fix ASCONF list handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 41/56] net: Fix skb_set_peeked use-after-free bug Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 32/56] vhost/scsi: potential memory corruption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 30/56] hfs,hfsplus: cache pages correctly between bnode_create and bnode_free Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 35/56] net/tipc: initialize security state for new connection socket Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 52/56] net/ipv6: Correct PIM6 mrt_lock handling Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 50/56] usbnet: Get EVENT_NO_RUNTIME_PM bit before it is cleared Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 44/56] ipv6: lock socket in ip6_datagram_connect() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 42/56] bridge: mdb: fix double add notification Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 33/56] x86: bpf_jit: fix compilation of large bpf programs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 37/56] net: pktgen: fix race between pktgen_thread_worker() and kthread_stop() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 45/56] bonding: fix destruction of bond with devices different from arphrd_ether Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 53/56] sctp: fix race on protocol/netns initialization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 47/56] netlink: dont hold mutex in rcu callback when releasing mmapd ring Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 36/56] bridge: mdb: zero out the local br_ip variable before use Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 48/56] rds: fix an integer overflow test in rds_info_getsockopt() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
Re: [PATCH 3.10 08/56] Input: synaptics - fix handling of disabling gesture mode Dmitry Torokhov <dmitry.torokhov@gmail.com> - 2015-09-29 16:00 +0200
Re: [PATCH 3.10 08/56] Input: synaptics - fix handling of disabling gesture mode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:20 +0200
[PATCH 3.10 56/56] Revert "iio: bmg160: IIO_BUFFER and IIO_TRIGGERED_BUFFER are required" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 38/56] net: call rcu_read_lock early in process_backlog Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 54/56] fib_rules: fix fib rule dumps across multiple skbs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 46/56] inet: frags: fix defragmented packets IP header for af_packet Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 34/56] ipv6: Make MLD packets to only be processed locally Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 51/56] ipv6: fix exthdrs offload registration in out_rt path Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 39/56] net: Clone skb before setting peeked flag Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:00 +0200
[PATCH 3.10 03/56] tg3: Fix temperature reporting Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 22/56] md/raid10: always set reshape_safe when initializing reshape_position. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 18/56] parisc: Filter out spurious interrupts in PA-RISC irq handler Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 13/56] Add radeon suspend/resume quirk for HP Compaq dc5750. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 16/56] NFSv4: dont set SETATTR for O_RDONLY|O_EXCL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 20/56] fs: if a coredump already exists, unlink and recreate with O_EXCL Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 08/56] Input: synaptics - fix handling of disabling gesture mode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 06/56] arm64: compat: fix vfp save/restore across signal handlers in big-endian Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 21/56] mmc: core: fix race condition in mmc_wait_data_done Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 24/56] hfs: fix B-tree corruption after insertion at position 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 19/56] vmscan: fix increasing nr_isolated incurred by putback unevictable pages Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 12/56] powerpc/rtas: Introduce rtas_get_sensor_fast() for IRQ handlers Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 11/56] powerpc/mm: Fix pte_pagesize_index() crash on 4K w/64K hash Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 07/56] arm64: head.S: initialise mdcr_el2 in el2_setup Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
[PATCH 3.10 26/56] IB/uverbs: Fix race between ib_uverbs_open and remove_one Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-09-29 16:10 +0200
Re: [PATCH 3.10 00/56] 3.10.90-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2015-09-29 19:00 +0200
Re: [PATCH 3.10 00/56] 3.10.90-stable review Guenter Roeck <linux@roeck-us.net> - 2015-09-29 23:20 +0200
Re: [PATCH 3.10 00/56] 3.10.90-stable review Sudip Mukherjee <sudipm.mukherjee@gmail.com> - 2015-09-30 07:50 +0200
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