user/sven/linux.git/security/device_cgroup.c, branch v3.9.7

device_cgroup: don't grab mutex in rcu callback

2013-02-22T01:22:15Z

Commit 103a197c0c4e ("security/device_cgroup: lock assert fails in dev_exception_clean()") grabs devcgroup_mutex to fix assert failure, but a mutex can't be grabbed in rcu callback. Since there shouldn't be any other references when css_free is called, mutex isn't needed for list cleanup in devcgroup_css_free(). Signed-off-by: Jerry Snitselaar Acked-by: Tejun Heo Acked-by: Aristeu Rozanski Cc: James Morris Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

security/device_cgroup: lock assert fails in dev_exception_clean()

2013-01-21T13:27:55Z

devcgroup_css_free() calls dev_exception_clean() without the devcgroup_mutex being locked. Shutting down a kvm virt was giving me the following trace: [36280.732764] ------------[ cut here ]------------ [36280.732778] WARNING: at /home/snits/dev/linux/security/device_cgroup.c:172 dev_exception_clean+0xa9/0xc0() [36280.732782] Hardware name: Studio XPS 8100 [36280.732785] Modules linked in: xt_REDIRECT fuse ebtable_nat ebtables ipt_MASQUERADE iptable_nat nf_nat_ipv4 nf_nat xt_CHECKSUM iptable_mangle bridge stp llc nf_conntrack_ipv4 ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 nf_defrag_ipv4 ip6table_filter it87 hwmon_vid xt_state nf_conntrack ip6_tables snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_intel snd_hda_codec snd_hwdep snd_seq coretemp snd_seq_device crc32c_intel snd_pcm snd_page_alloc snd_timer snd broadcom tg3 serio_raw i7core_edac edac_core ptp pps_core lpc_ich pcspkr mfd_core soundcore microcode i2c_i801 nfsd auth_rpcgss nfs_acl lockd vhost_net sunrpc tun macvtap macvlan kvm_intel kvm uinput binfmt_misc autofs4 usb_storage firewire_ohci firewire_core crc_itu_t radeon drm_kms_helper ttm [36280.732921] Pid: 933, comm: libvirtd Tainted: G W 3.8.0-rc3-00307-g4c217de #1 [36280.732922] Call Trace: [36280.732927] [] warn_slowpath_common+0x93/0xc0 [36280.732930] [] warn_slowpath_null+0x1a/0x20 [36280.732932] [] dev_exception_clean+0xa9/0xc0 [36280.732934] [] devcgroup_css_free+0x1a/0x30 [36280.732938] [] cgroup_diput+0x76/0x210 [36280.732941] [] d_delete+0x120/0x180 [36280.732943] [] vfs_rmdir+0xef/0x130 [36280.732945] [] do_rmdir+0x107/0x1c0 [36280.732949] [] ? trace_hardirqs_on_thunk+0x3a/0x3f [36280.732951] [] sys_rmdir+0x16/0x20 [36280.732954] [] system_call_fastpath+0x16/0x1b [36280.732956] ---[ end trace ca39dced899a7d9f ]--- Signed-off-by: Jerry Snitselaar Cc: stable@kernel.org Signed-off-by: James Morris

cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free()

2012-11-19T16:13:38Z

Rename cgroup_subsys css lifetime related callbacks to better describe what their roles are. Also, update documentation. Signed-off-by: Tejun Heo Acked-by: Li Zefan

device_cgroup: add lockdep asserts

2012-11-06T20:28:04Z

device_cgroup uses RCU safe ->exceptions list which is write-protected by devcgroup_mutex and has had some issues using locking correctly. Add lockdep asserts to utility functions so that future errors can be easily detected. Signed-off-by: Tejun Heo Acked-by: Serge E. Hallyn Cc: Aristeu Rozanski Cc: Li Zefan

device_cgroup: fix RCU usage

2012-11-06T20:25:51Z

dev_cgroup->exceptions is protected with devcgroup_mutex for writes and RCU for reads; however, RCU usage isn't correct. * dev_exception_clean() doesn't use RCU variant of list_del() and kfree(). The function can race with may_access() and may_access() may end up dereferencing already freed memory. Use list_del_rcu() and kfree_rcu() instead. * may_access() may be called only with RCU read locked but doesn't use RCU safe traversal over ->exceptions. Use list_for_each_entry_rcu(). Signed-off-by: Tejun Heo Acked-by: Serge E. Hallyn Cc: stable@vger.kernel.org Cc: Aristeu Rozanski Cc: Li Zefan

device_cgroup: fix unchecked cgroup parent usage

2012-11-06T15:25:20Z

In 4cef7299b478687 ("device_cgroup: add proper checking when changing default behavior") the cgroup parent usage is unchecked. root will not have a parent and trying to use device.{allow,deny} will cause problems. For some reason my stressing scripts didn't test the root directory so I didn't catch it on my regular tests. Signed-off-by: Aristeu Rozanski Cc: Li Zefan Cc: James Morris Cc: Pavel Emelyanov Acked-by: Serge E. Hallyn Cc: Jiri Slaby Cc: Tejun Heo Signed-off-by: Tejun Heo

device_cgroup: add proper checking when changing default behavior

2012-10-25T21:37:52Z

Before changing a group's default behavior to ALLOW, we must check if its parent's behavior is also ALLOW. Signed-off-by: Aristeu Rozanski Cc: Tejun Heo Cc: Li Zefan Cc: James Morris Cc: Pavel Emelyanov Acked-by: Serge Hallyn Cc: Jiri Slaby Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

device_cgroup: stop using simple_strtoul()

2012-10-25T21:37:52Z

Convert the code to use kstrtou32() instead of simple_strtoul() which is deprecated. The real size of the variables are u32, so use kstrtou32 instead of kstrtoul Signed-off-by: Aristeu Rozanski Cc: Dave Jones Cc: Tejun Heo Cc: Li Zefan Cc: James Morris Cc: Pavel Emelyanov Acked-by: Serge Hallyn Cc: Jiri Slaby Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

device_cgroup: rename deny_all to behavior

2012-10-25T21:37:52Z

This was done in a v2 patch but v1 ended up being committed. The variable name is less confusing and stores the default behavior when no matching exception exists. Signed-off-by: Aristeu Rozanski Cc: Dave Jones Cc: Tejun Heo Cc: Li Zefan Cc: James Morris Cc: Pavel Emelyanov Acked-by: Serge Hallyn Cc: Jiri Slaby Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

cgroup: fix invalid rcu dereference

2012-10-25T21:37:52Z

Commit ad676077a2ae ("device_cgroup: convert device_cgroup internally to policy + exceptions") removed rcu locks which are needed in task_devcgroup called in this chain: devcgroup_inode_mknod OR __devcgroup_inode_permission -> __devcgroup_inode_permission -> task_devcgroup -> task_subsys_state -> task_subsys_state_check. Change the code so that task_devcgroup is safely called with rcu read lock held. =============================== [ INFO: suspicious RCU usage. ] 3.6.0-rc5-next-20120913+ #42 Not tainted ------------------------------- include/linux/cgroup.h:553 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 2 locks held by kdevtmpfs/23: #0: (sb_writers){.+.+.+}, at: [] mnt_want_write+0x1f/0x50 #1: (&sb->s_type->i_mutex_key#3/1){+.+.+.}, at: [] kern_path_create+0x7f/0x170 stack backtrace: Pid: 23, comm: kdevtmpfs Not tainted 3.6.0-rc5-next-20120913+ #42 Call Trace: lockdep_rcu_suspicious+0xfd/0x130 devcgroup_inode_mknod+0x19d/0x240 vfs_mknod+0x71/0xf0 handle_create.isra.2+0x72/0x200 devtmpfsd+0x114/0x140 ? handle_create.isra.2+0x200/0x200 kthread+0xd6/0xe0 kernel_thread_helper+0x4/0x10 Signed-off-by: Jiri Slaby Cc: Dave Jones Cc: Tejun Heo Cc: Li Zefan Cc: James Morris Cc: Pavel Emelyanov Acked-by: Serge Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds