BMC/Intel-BMC/linux.git/drivers/net/ppp/ppp_generic.c, branch dev-4.7

ppp: defer netns reference release for ppp channel

2016-07-09T03:46:37+00:00

Matt reported that we have a NULL pointer dereference in ppp_pernet() from ppp_connect_channel(), i.e. pch->chan_net is NULL. This is due to that a parallel ppp_unregister_channel() could happen while we are in ppp_connect_channel(), during which pch->chan_net set to NULL. Since we need a reference to net per channel, it makes sense to sync the refcnt with the life time of the channel, therefore we should release this reference when we destroy it. Fixes: 1f461dcdd296 ("ppp: take reference on channels netns") Reported-by: Matt Bennett Cc: Paul Mackerras Cc: linux-ppp@vger.kernel.org Cc: Guillaume Nault Cc: Cyrill Gorcunov Signed-off-by: Cong Wang Reviewed-by: Cyrill Gorcunov Signed-off-by: David S. Miller

ppp: add rtnetlink device creation support

2016-04-29T20:09:44+00:00

Define PPP device handler for use with rtnetlink. The only PPP specific attribute is IFLA_PPP_DEV_FD. It is mandatory and contains the file descriptor of the associated /dev/ppp instance (the file descriptor which would have been used for ioctl(PPPIOCNEWUNIT) in the ioctl-based API). The PPP device is removed when this file descriptor is released (same behaviour as with ioctl based PPP devices). PPP devices created with the rtnetlink API behave like the ones created with ioctl(PPPIOCNEWUNIT). In particular existing ioctls work the same way, no matter how the PPP device was created. The rtnl callbacks are also assigned to ioctl based PPP devices. This way, rtnl messages have the same effect on any PPP devices. The immediate effect is that all PPP devices, even ioctl-based ones, can now be removed with "ip link del". A minor difference still exists between ioctl and rtnl based PPP interfaces: in the device name, the number following the "ppp" prefix corresponds to the PPP unit number for ioctl based devices, while it is just an unrelated incrementing index for rtnl ones. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

ppp: define reusable device creation functions

2016-04-29T20:09:44+00:00

Move PPP device initialisation and registration out of ppp_create_interface(). This prepares code for device registration with rtnetlink. While there, simplify the prototype of ppp_create_interface(): * Since ppp_dev_configure() takes care of setting file->private_data, there's no need to return a ppp structure to ppp_unattached_ioctl() anymore. * The unit parameter is made read/write so that ppp_create_interface() can tell which unit number has been assigned. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

ppp: take reference on channels netns

2016-03-23T18:35:31+00:00

Let channels hold a reference on their network namespace. Some channel types, like ppp_async and ppp_synctty, can have their userspace controller running in a different namespace. Therefore they can't rely on them to preclude their netns from being removed from under them. ================================================================== BUG: KASAN: use-after-free in ppp_unregister_channel+0x372/0x3a0 at addr ffff880064e217e0 Read of size 8 by task syz-executor/11581 ============================================================================= BUG net_namespace (Not tainted): kasan: bad access detected ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: Allocated in copy_net_ns+0x6b/0x1a0 age=92569 cpu=3 pid=6906 [< none >] ___slab_alloc+0x4c7/0x500 kernel/mm/slub.c:2440 [< none >] __slab_alloc+0x4c/0x90 kernel/mm/slub.c:2469 [< inline >] slab_alloc_node kernel/mm/slub.c:2532 [< inline >] slab_alloc kernel/mm/slub.c:2574 [< none >] kmem_cache_alloc+0x23a/0x2b0 kernel/mm/slub.c:2579 [< inline >] kmem_cache_zalloc kernel/include/linux/slab.h:597 [< inline >] net_alloc kernel/net/core/net_namespace.c:325 [< none >] copy_net_ns+0x6b/0x1a0 kernel/net/core/net_namespace.c:360 [< none >] create_new_namespaces+0x2f6/0x610 kernel/kernel/nsproxy.c:95 [< none >] copy_namespaces+0x297/0x320 kernel/kernel/nsproxy.c:150 [< none >] copy_process.part.35+0x1bf4/0x5760 kernel/kernel/fork.c:1451 [< inline >] copy_process kernel/kernel/fork.c:1274 [< none >] _do_fork+0x1bc/0xcb0 kernel/kernel/fork.c:1723 [< inline >] SYSC_clone kernel/kernel/fork.c:1832 [< none >] SyS_clone+0x37/0x50 kernel/kernel/fork.c:1826 [< none >] entry_SYSCALL_64_fastpath+0x16/0x7a kernel/arch/x86/entry/entry_64.S:185 INFO: Freed in net_drop_ns+0x67/0x80 age=575 cpu=2 pid=2631 [< none >] __slab_free+0x1fc/0x320 kernel/mm/slub.c:2650 [< inline >] slab_free kernel/mm/slub.c:2805 [< none >] kmem_cache_free+0x2a0/0x330 kernel/mm/slub.c:2814 [< inline >] net_free kernel/net/core/net_namespace.c:341 [< none >] net_drop_ns+0x67/0x80 kernel/net/core/net_namespace.c:348 [< none >] cleanup_net+0x4e5/0x600 kernel/net/core/net_namespace.c:448 [< none >] process_one_work+0x794/0x1440 kernel/kernel/workqueue.c:2036 [< none >] worker_thread+0xdb/0xfc0 kernel/kernel/workqueue.c:2170 [< none >] kthread+0x23f/0x2d0 kernel/drivers/block/aoe/aoecmd.c:1303 [< none >] ret_from_fork+0x3f/0x70 kernel/arch/x86/entry/entry_64.S:468 INFO: Slab 0xffffea0001938800 objects=3 used=0 fp=0xffff880064e20000 flags=0x5fffc0000004080 INFO: Object 0xffff880064e20000 @offset=0 fp=0xffff880064e24200 CPU: 1 PID: 11581 Comm: syz-executor Tainted: G B 4.4.0+ Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014 00000000ffffffff ffff8800662c7790 ffffffff8292049d ffff88003e36a300 ffff880064e20000 ffff880064e20000 ffff8800662c77c0 ffffffff816f2054 ffff88003e36a300 ffffea0001938800 ffff880064e20000 0000000000000000 Call Trace: [< inline >] __dump_stack kernel/lib/dump_stack.c:15 [] dump_stack+0x6f/0xa2 kernel/lib/dump_stack.c:50 [] print_trailer+0xf4/0x150 kernel/mm/slub.c:654 [] object_err+0x2f/0x40 kernel/mm/slub.c:661 [< inline >] print_address_description kernel/mm/kasan/report.c:138 [] kasan_report_error+0x215/0x530 kernel/mm/kasan/report.c:236 [< inline >] kasan_report kernel/mm/kasan/report.c:259 [] __asan_report_load8_noabort+0x3e/0x40 kernel/mm/kasan/report.c:280 [< inline >] ? ppp_pernet kernel/include/linux/compiler.h:218 [] ? ppp_unregister_channel+0x372/0x3a0 kernel/drivers/net/ppp/ppp_generic.c:2392 [< inline >] ppp_pernet kernel/include/linux/compiler.h:218 [] ppp_unregister_channel+0x372/0x3a0 kernel/drivers/net/ppp/ppp_generic.c:2392 [< inline >] ? ppp_pernet kernel/drivers/net/ppp/ppp_generic.c:293 [] ? ppp_unregister_channel+0xe6/0x3a0 kernel/drivers/net/ppp/ppp_generic.c:2392 [] ppp_asynctty_close+0xa3/0x130 kernel/drivers/net/ppp/ppp_async.c:241 [] ? async_lcp_peek+0x5b0/0x5b0 kernel/drivers/net/ppp/ppp_async.c:1000 [] tty_ldisc_close.isra.1+0x99/0xe0 kernel/drivers/tty/tty_ldisc.c:478 [] tty_ldisc_kill+0x40/0x170 kernel/drivers/tty/tty_ldisc.c:744 [] tty_ldisc_release+0x1b3/0x260 kernel/drivers/tty/tty_ldisc.c:772 [] tty_release+0xac1/0x13e0 kernel/drivers/tty/tty_io.c:1901 [] ? release_tty+0x320/0x320 kernel/drivers/tty/tty_io.c:1688 [] __fput+0x236/0x780 kernel/fs/file_table.c:208 [] ____fput+0x15/0x20 kernel/fs/file_table.c:244 [] task_work_run+0x16b/0x200 kernel/kernel/task_work.c:115 [< inline >] exit_task_work kernel/include/linux/task_work.h:21 [] do_exit+0x8b5/0x2c60 kernel/kernel/exit.c:750 [] ? debug_check_no_locks_freed+0x290/0x290 kernel/kernel/locking/lockdep.c:4123 [] ? mm_update_next_owner+0x6f0/0x6f0 kernel/kernel/exit.c:357 [] ? __dequeue_signal+0x136/0x470 kernel/kernel/signal.c:550 [] ? recalc_sigpending_tsk+0x13b/0x180 kernel/kernel/signal.c:145 [] do_group_exit+0x108/0x330 kernel/kernel/exit.c:880 [] get_signal+0x5e4/0x14f0 kernel/kernel/signal.c:2307 [< inline >] ? kretprobe_table_lock kernel/kernel/kprobes.c:1113 [] ? kprobe_flush_task+0xb5/0x450 kernel/kernel/kprobes.c:1158 [] do_signal+0x83/0x1c90 kernel/arch/x86/kernel/signal.c:712 [] ? recycle_rp_inst+0x310/0x310 kernel/include/linux/list.h:655 [] ? setup_sigcontext+0x780/0x780 kernel/arch/x86/kernel/signal.c:165 [] ? finish_task_switch+0x424/0x5f0 kernel/kernel/sched/core.c:2692 [< inline >] ? finish_lock_switch kernel/kernel/sched/sched.h:1099 [] ? finish_task_switch+0x120/0x5f0 kernel/kernel/sched/core.c:2678 [< inline >] ? context_switch kernel/kernel/sched/core.c:2807 [] ? __schedule+0x919/0x1bd0 kernel/kernel/sched/core.c:3283 [] exit_to_usermode_loop+0xf1/0x1a0 kernel/arch/x86/entry/common.c:247 [< inline >] prepare_exit_to_usermode kernel/arch/x86/entry/common.c:282 [] syscall_return_slowpath+0x19f/0x210 kernel/arch/x86/entry/common.c:344 [] int_ret_from_sys_call+0x25/0x9f kernel/arch/x86/entry/entry_64.S:281 Memory state around the buggy address: ffff880064e21680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff880064e21700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff880064e21780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff880064e21800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff880064e21880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Fixes: 273ec51dd7ce ("net: ppp_generic - introduce net-namespace functionality v2") Reported-by: Baozeng Ding Signed-off-by: Guillaume Nault Reviewed-by: Cyrill Gorcunov Signed-off-by: David S. Miller

ppp: ensure file->private_data can't be overridden

2016-03-16T23:35:06+00:00

Locking ppp_mutex must be done before dereferencing file->private_data, otherwise it could be modified before ppp_unattached_ioctl() takes the lock. This could lead ppp_unattached_ioctl() to override ->private_data, thus leaking reference to the ppp_file previously pointed to. v2: lock all ppp_ioctl() instead of just checking private_data in ppp_unattached_ioctl(), to avoid ambiguous behaviour. Fixes: f3ff8a4d80e8 ("ppp: push BKL down into the driver") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2016-03-08T17:34:12+00:00

Several cases of overlapping changes, as well as one instance (vxlan) of a bug fix in 'net' overlapping with code movement in 'net-next'. Signed-off-by: David S. Miller

ppp: release rtnl mutex when interface creation fails

2016-03-07T21:11:31+00:00

Add missing rtnl_unlock() in the error path of ppp_create_interface(). Fixes: 58a89ecaca53 ("ppp: fix lockdep splat in ppp_dev_uninit()") Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

ppp: lock ppp->flags in ppp_read() and ppp_poll()

2016-03-01T21:15:07+00:00

ppp_read() and ppp_poll() can be called concurrently with ppp_ioctl(). In this case, ppp_ioctl() might call ppp_ccp_closed(), which may update ppp->flags while ppp_read() or ppp_poll() is reading it. The update done by ppp_ccp_closed() isn't atomic due to the bit mask operation ('ppp->flags &= ~(SC_CCP_OPEN | SC_CCP_UP)'), so concurrent readers might get transient values. Reading incorrect ppp->flags may disturb the 'ppp->flags & SC_LOOP_TRAFFIC' test in ppp_read() and ppp_poll(), which in turn can lead to improper decision on whether the PPP unit file is ready for reading or not. Since ppp_ccp_closed() is protected by the Rx and Tx locks (with ppp_lock()), taking the Rx lock is enough for ppp_read() and ppp_poll() to guarantee that ppp_ccp_closed() won't update ppp->flags concurrently. The same reasoning applies to ppp->n_channels. The 'n_channels' field can also be written to concurrently by ppp_ioctl() (through ppp_connect_channel() or ppp_disconnect_channel()). These writes aren't atomic (simple increment/decrement), but are protected by both the Rx and Tx locks (like in the ppp->flags case). So holding the Rx lock before reading ppp->n_channels also prevents concurrent writes. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

ppp: clarify parsing of user supplied data in ppp_set_compress()

2016-02-25T04:52:51+00:00

* Split big conditional statement. * Check (data.length <= CCP_MAX_OPTION_LENGTH) only once. * Don't read ccp_option[1] if not initialised. Reading uninitialised ccp_option[1] was harmless, because this could only happen when data.length was 0 or 1. So even then, we couldn't pass the (ccp_option[1] < 2 || ccp_option[1] > data.length) test anyway. Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller

ppp: declare ppp devices as enumerated interfaces

2015-12-14T21:20:57+00:00

Let user space be aware of the naming scheme used by ppp interfaces (visible in /sys/class/net//name_assign_type). Signed-off-by: Guillaume Nault Signed-off-by: David S. Miller