user/sven/linux.git/include/linux/sysctl.h, branch v4.9.6

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

2016-10-06T16:52:23Z

Pull namespace updates from Eric Biederman: "This set of changes is a number of smaller things that have been overlooked in other development cycles focused on more fundamental change. The devpts changes are small things that were a distraction until we managed to kill off DEVPTS_MULTPLE_INSTANCES. There is an trivial regression fix to autofs for the unprivileged mount changes that went in last cycle. A pair of ioctls has been added by Andrey Vagin making it is possible to discover the relationships between namespaces when referring to them through file descriptors. The big user visible change is starting to add simple resource limits to catch programs that misbehave. With namespaces in general and user namespaces in particular allowing users to use more kinds of resources, it has become important to have something to limit errant programs. Because the purpose of these limits is to catch errant programs the code needs to be inexpensive to use as it always on, and the default limits need to be high enough that well behaved programs on well behaved systems don't encounter them. To this end, after some review I have implemented per user per user namespace limits, and use them to limit the number of namespaces. The limits being per user mean that one user can not exhause the limits of another user. The limits being per user namespace allow contexts where the limit is 0 and security conscious folks can remove from their threat anlysis the code used to manage namespaces (as they have historically done as it root only). At the same time the limits being per user namespace allow other parts of the system to use namespaces. Namespaces are increasingly being used in application sand boxing scenarios so an all or nothing disable for the entire system for the security conscious folks makes increasing use of these sandboxes impossible. There is also added a limit on the maximum number of mounts present in a single mount namespace. It is nontrivial to guess what a reasonable system wide limit on the number of mount structure in the kernel would be, especially as it various based on how a system is using containers. A limit on the number of mounts in a mount namespace however is much easier to understand and set. In most cases in practice only about 1000 mounts are used. Given that some autofs scenarious have the potential to be 30,000 to 50,000 mounts I have set the default limit for the number of mounts at 100,000 which is well above every known set of users but low enough that the mount hash tables don't degrade unreaonsably. These limits are a start. I expect this estabilishes a pattern that other limits for resources that namespaces use will follow. There has been interest in making inotify event limits per user per user namespace as well as interest expressed in making details about what is going on in the kernel more visible" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (28 commits) autofs: Fix automounts by using current_real_cred()->uid mnt: Add a per mount namespace limit on the number of mounts netns: move {inc,dec}_net_namespaces into #ifdef nsfs: Simplify __ns_get_path tools/testing: add a test to check nsfs ioctl-s nsfs: add ioctl to get a parent namespace nsfs: add ioctl to get an owning user namespace for ns file descriptor kernel: add a helper to get an owning user namespace for a namespace devpts: Change the owner of /dev/pts/ptmx to the mounter of /dev/pts devpts: Remove sync_filesystems devpts: Make devpts_kill_sb safe if fsi is NULL devpts: Simplify devpts_mount by using mount_nodev devpts: Move the creation of /dev/pts/ptmx into fill_super devpts: Move parse_mount_options into fill_super userns: When the per user per user namespace limit is reached return ENOSPC userns; Document per user per user namespace limits. mntns: Add a limit on the number of mount namespaces. netns: Add a limit on the number of net namespaces cgroupns: Add a limit on the number of cgroup namespaces ipcns: Add a limit on the number of ipc namespaces ...

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

2016-08-30T04:54:02Z

All three conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller

sysctl: handle error writing UINT_MAX to u32 fields

2016-08-27T00:39:35Z

We have scripts which write to certain fields on 3.18 kernels but this seems to be failing on 4.4 kernels. An entry which we write to here is xfrm_aevent_rseqth which is u32. echo 4294967295 > /proc/sys/net/core/xfrm_aevent_rseqth Commit 230633d109e3 ("kernel/sysctl.c: detect overflows when converting to int") prevented writing to sysctl entries when integer overflow occurs. However, this does not apply to unsigned integers. Heinrich suggested that we introduce a new option to handle 64 bit limits and set min as 0 and max as UINT_MAX. This might not work as it leads to issues similar to __do_proc_doulongvec_minmax. Alternatively, we would need to change the datatype of the entry to 64 bit. static int __do_proc_doulongvec_minmax(void *data, struct ctl_table { i = (unsigned long *) data; //This cast is causing to read beyond the size of data (u32) vleft = table->maxlen / sizeof(unsigned long); //vleft is 0 because maxlen is sizeof(u32) which is lesser than sizeof(unsigned long) on x86_64. Introduce a new proc handler proc_douintvec. Individual proc entries will need to be updated to use the new handler. [akpm@linux-foundation.org: coding-style fixes] Fixes: 230633d109e3 ("kernel/sysctl.c:detect overflows when converting to int") Link: http://lkml.kernel.org/r/1471479806-5252-1-git-send-email-subashab@codeaurora.org Signed-off-by: Subash Abhinov Kasiviswanathan Cc: Heinrich Schuchardt Cc: Kees Cook Cc: "David S. Miller" Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

net: make net namespace sysctls belong to container's owner

2016-08-15T04:08:58Z

If net namespace is attached to a user namespace let's make container's root owner of sysctls affecting said network namespace instead of global root. This also allows us to clean up net_ctl_permissions() because we do not need to fudge permissions anymore for the container's owner since it now owns the objects in question. Acked-by: "Eric W. Biederman" Signed-off-by: Dmitry Torokhov Signed-off-by: David S. Miller

sysctl: Stop implicitly passing current into sysctl_table_root.lookup

2016-08-08T14:17:16Z

Passing nsproxy into sysctl_table_root.lookup was a premature optimization in attempt to avoid depending on current. The directory /proc/self/sys has not appeared and if and when it does this code will need to be reviewed closely and reworked anyway. So remove the premature optimization. Acked-by: Kees Cook Acked-by: Serge Hallyn Signed-off-by: "Eric W. Biederman"

uapi: move forward declarations of internal structures

2016-08-02T21:31:41Z

Don't user forward declarations of internal kernel structures in headers exported to userspace. Move "struct completion;". Move "struct task_struct;". Link: http://lkml.kernel.org/r/20160713215808.GA22486@p183.telecom.by Signed-off-by: Alexey Dobriyan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sysctl: Allow creating permanently empty directories that serve as mountpoints.

2015-07-01T15:36:39Z

Add a magic sysctl table sysctl_mount_point that when used to create a directory forces that directory to be permanently empty. Update the code to use make_empty_dir_inode when accessing permanently empty directories. Update the code to not allow adding to permanently empty directories. Update /proc/sys/fs/binfmt_misc to be a permanently empty directory. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman"

kernel/sysctl.c: threads-max observe limits

2015-04-17T13:04:07Z

Users can change the maximum number of threads by writing to /proc/sys/kernel/threads-max. With the patch the value entered is checked against the same limits that apply when fork_init is called. Signed-off-by: Heinrich Schuchardt Cc: Oleg Nesterov Cc: Ingo Molnar Cc: Guenter Roeck Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sysctl: remove typedef ctl_table

2014-08-08T22:57:24Z

Remove the final user, and the typedef itself. Signed-off-by: Joe Perches Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

sysctl: Pass useful parameters to sysctl permissions

2012-11-19T01:30:55Z

- Current is implicitly avaiable so passing current->nsproxy isn't useful. - The ctl_table_header is needed to find how the sysctl table is connected to the rest of sysctl. - ctl_table_root is avaiable in the ctl_table_header so no need to it. With these changes it becomes possible to write a version of net_sysctl_permission that takes into account the network namespace of the sysctl table, an important feature in extending the user namespace. Acked-by: Serge Hallyn Signed-off-by: "Eric W. Biederman" Signed-off-by: David S. Miller