user/sven/linux.git/ipc/mqueue.c, branch v4.17.4

Revert "mqueue: switch to on-demand creation of internal mount"

2018-03-25T00:34:23Z

This reverts commit 36735a6a2b5e042db1af956ce4bcc13f3ff99e21. Aleksa Sarai writes: > [REGRESSION v4.16-rc6] [PATCH] mqueue: forbid unprivileged user access to internal mount > > Felix reported weird behaviour on 4.16.0-rc6 with regards to mqueue[1], > which was introduced by 36735a6a2b5e ("mqueue: switch to on-demand > creation of internal mount"). > > Basically, the reproducer boils down to being able to mount mqueue if > you create a new user namespace, even if you don't unshare the IPC > namespace. > > Previously this was not possible, and you would get an -EPERM. The mount > is the *host* mqueue mount, which is being cached and just returned from > mqueue_mount(). To be honest, I'm not sure if this is safe or not (or if > it was intentional -- since I'm not familiar with mqueue). > > To me it looks like there is a missing permission check. I've included a > patch below that I've compile-tested, and should block the above case. > Can someone please tell me if I'm missing something? Is this actually > safe? > > [1]: https://github.com/docker/docker/issues/36674 The issue is a lot deeper than a missing permission check. sb->s_user_ns was is improperly set as well. So in addition to the filesystem being mounted when it should not be mounted, so things are not allow that should be. We are practically to the release of 4.16 and there is no agreement between Al Viro and myself on what the code should looks like to fix things properly. So revert the code to what it was before so that we can take our time and discuss this properly. Fixes: 36735a6a2b5e ("mqueue: switch to on-demand creation of internal mount") Reported-by: Felix Abecassis Reported-by: Aleksa Sarai Signed-off-by: "Eric W. Biederman"

vfs: do bulk POLL* -> EPOLL* replacement

2018-02-11T22:34:03Z

This is the mindless scripted replacement of kernel use of POLL* variables as described by Al, done by this script: for V in IN OUT PRI ERR RDNORM RDBAND WRNORM WRBAND HUP RDHUP NVAL MSG; do L=`git grep -l -w POLL$V | grep -v '^t' | grep -v /um/ | grep -v '^sa' | grep -v '/poll.h$'|grep -v '^D'` for f in $L; do sed -i "-es/^$[^\"]*$$\$/\\1E\\2/" $f; done done with de-mangling cleanups yet to come. NOTE! On almost all architectures, the EPOLL* constants have the same values as the POLL* constants do. But they keyword here is "almost". For various bad reasons they aren't the same, and epoll() doesn't actually work quite correctly in some cases due to this on Sparc et al. The next patch from Al will sort out the final differences, and we should be all done. Scripted-by: Al Viro Signed-off-by: Linus Torvalds

ipc/mqueue.c: have RT tasks queue in by priority in wq_add()

2018-02-07T02:32:46Z

Previous behavior added tasks to the work queue using the static_prio value instead of the dynamic priority value in prio. This caused RT tasks to be added to the work queue in a FIFO manner rather than by priority. Normal tasks were handled by priority. This fix utilizes the dynamic priority of the task to ensure that both RT and normal tasks are added to the work queue in priority order. Utilizing the dynamic priority (prio) rather than the base priority (normal_prio) was chosen to ensure that if a task had a boosted priority when it was added to the work queue, it would be woken sooner to to ensure that it releases any other locks it may be holding in a more timely manner. It is understood that the task could have a lower priority when it wakes than when it was added to the queue in this (unlikely) case. Link: http://lkml.kernel.org/r/1513006652-7014-1-git-send-email-jhaws@sdl.usu.edu Signed-off-by: Jonathan Haws Reviewed-by: Steven Rostedt (VMware) Reviewed-by: Davidlohr Bueso Cc: Ingo Molnar Cc: Al Viro Cc: Arnd Bergmann Cc: Deepa Dinamani Cc: Thomas Gleixner Cc: Sebastian Andrzej Siewior Cc: Manfred Spraul Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2018-01-31T02:32:21Z

Pull mqueue/bpf vfs cleanups from Al Viro: "mqueue and bpf go through rather painful and similar contortions to create objects in their dentry trees. Provide a primitive for doing that without abusing ->mknod(), switch bpf and mqueue to it. Another mqueue-related thing that has ended up in that branch is on-demand creation of internal mount (based upon the work of Giuseppe Scrivano)" * 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: mqueue: switch to on-demand creation of internal mount tidy do_mq_open() up a bit mqueue: clean prepare_open() up do_mq_open(): move all work prior to dentry_open() into a helper mqueue: fold mq_attr_ok() into mqueue_get_inode() move dentry_open() calls up into do_mq_open() mqueue: switch to vfs_mkobj(), quit abusing ->d_fsdata bpf_obj_do_pin(): switch to vfs_mkobj(), quit abusing ->mknod() new primitive: vfs_mkobj()

Merge branch 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2018-01-31T01:58:07Z

Pull poll annotations from Al Viro: "This introduces a __bitwise type for POLL### bitmap, and propagates the annotations through the tree. Most of that stuff is as simple as 'make ->poll() instances return __poll_t and do the same to local variables used to hold the future return value'. Some of the obvious brainos found in process are fixed (e.g. POLLIN misspelled as POLL_IN). At that point the amount of sparse warnings is low and most of them are for genuine bugs - e.g. ->poll() instance deciding to return -EINVAL instead of a bitmap. I hadn't touched those in this series - it's large enough as it is. Another problem it has caught was eventpoll() ABI mess; select.c and eventpoll.c assumed that corresponding POLL### and EPOLL### were equal. That's true for some, but not all of them - EPOLL### are arch-independent, but POLL### are not. The last commit in this series separates userland POLL### values from the (now arch-independent) kernel-side ones, converting between them in the few places where they are copied to/from userland. AFAICS, this is the least disruptive fix preserving poll(2) ABI and making epoll() work on all architectures. As it is, it's simply broken on sparc - try to give it EPOLLWRNORM and it will trigger only on what would've triggered EPOLLWRBAND on other architectures. EPOLLWRBAND and EPOLLRDHUP, OTOH, are never triggered at all on sparc. With this patch they should work consistently on all architectures" * 'misc.poll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (37 commits) make kernel-side POLL... arch-independent eventpoll: no need to mask the result of epi_item_poll() again eventpoll: constify struct epoll_event pointers debugging printk in sg_poll() uses %x to print POLL... bitmap annotate poll(2) guts 9p: untangle ->poll() mess ->si_band gets POLL... bitmap stored into a user-visible long field ring_buffer_poll_wait() return value used as return value of ->poll() the rest of drivers/*: annotate ->poll() instances media: annotate ->poll() instances fs: annotate ->poll() instances ipc, kernel, mm: annotate ->poll() instances net: annotate ->poll() instances apparmor: annotate ->poll() instances tomoyo: annotate ->poll() instances sound: annotate ->poll() instances acpi: annotate ->poll() instances crypto: annotate ->poll() instances block: annotate ->poll() instances x86: annotate ->poll() instances ...

signal: Ensure generic siginfos the kernel sends have all bits initialized

2018-01-12T20:21:07Z

Call clear_siginfo to ensure stack allocated siginfos are fully initialized before being passed to the signal sending functions. This ensures that if there is the kind of confusion documented by TRAP_FIXME, FPE_FIXME, or BUS_FIXME the kernel won't send unitialized data to userspace when the kernel generates a signal with SI_USER but the copy to userspace assumes it is a different kind of signal, and different fields are initialized. This also prepares the way for turning copy_siginfo_to_user into a copy_to_user, by removing the need in many cases to perform a field by field copy simply to skip the uninitialized fields. Signed-off-by: "Eric W. Biederman"

mqueue: switch to on-demand creation of internal mount

2018-01-05T16:54:37Z

Instead of doing that upon each ipcns creation, we do that the first time mq_open(2) or mqueue mount is done in an ipcns. What's more, doing that allows to get rid of mount_ns() use - we can go with considerably cheaper mount_nodev(), avoiding the loop over all mqueue superblock instances; ipcns->mq_mnt is used to locate preexisting instance in O(1) time instead of O(instances) mount_ns() would've cost us. Based upon the version by Giuseppe Scrivano ; I've added handling of userland mqueue mounts (original had been broken in that area) and added a switch to mount_nodev(). Signed-off-by: Al Viro

tidy do_mq_open() up a bit

2018-01-05T16:54:36Z

Signed-off-by: Al Viro

mqueue: clean prepare_open() up

2018-01-05T16:54:36Z

Signed-off-by: Al Viro

do_mq_open(): move all work prior to dentry_open() into a helper

2018-01-05T16:54:35Z

Signed-off-by: Al Viro