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* fs: warn about impending deprecation of mandatory locksJeff Layton2021-08-261-1/+5
| | | | | | | | | | | | [ Upstream commit fdd92b64d15bc4aec973caa25899afd782402e68 ] We've had CONFIG_MANDATORY_FILE_LOCKING since 2015 and a lot of distros have disabled it. Warn the stragglers that still use "-o mand" that we'll be dropping support for that mount option. Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
* ovl: prevent private clone if bind mount is not allowedMiklos Szeredi2021-08-151-14/+28
| | | | | | | | | | | | | | | | | commit 427215d85e8d1476da1a86b8d67aceb485eb3631 upstream. Add the following checks from __do_loopback() to clone_private_mount() as well: - verify that the mount is in the current namespace - verify that there are no locked children Reported-by: Alois Wohlschlager <alois1@gmx-topmail.de> Fixes: c771d683a62e ("vfs: introduce clone_private_mount()") Cc: <stable@vger.kernel.org> # v3.18 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* fs/namespace.c: WARN if mnt_count has become negativeEric Biggers2021-01-061-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | [ Upstream commit edf7ddbf1c5eb98b720b063b73e20e8a4a1ce673 ] Missing calls to mntget() (or equivalently, too many calls to mntput()) are hard to detect because mntput() delays freeing mounts using task_work_add(), then again using call_rcu(). As a result, mnt_count can often be decremented to -1 without getting a KASAN use-after-free report. Such cases are still bugs though, and they point to real use-after-frees being possible. For an example of this, see the bug fixed by commit 1b0b9cc8d379 ("vfs: fsmount: add missing mntget()"), discussed at https://lkml.kernel.org/linux-fsdevel/20190605135401.GB30925@xxxxxxxxxxxxxxxxxxxxxxxxx/T/#u. This bug *should* have been trivial to find. But actually, it wasn't found until syzkaller happened to use fchdir() to manipulate the reference count just right for the bug to be noticeable. Address this by making mntput_no_expire() issue a WARN if mnt_count has become negative. Suggested-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
* fs/namespace.c: fix use-after-free of mount in mnt_warn_timestamp_expiry()Eric Biggers2019-10-161-8/+7
| | | | | | | | | | | | | | After do_add_mount() returns success, the caller doesn't hold a reference to the 'struct mount' anymore. So it's invalid to access it in mnt_warn_timestamp_expiry(). Fix it by calling mnt_warn_timestamp_expiry() before do_add_mount() rather than after, and adjusting the warning message accordingly. Reported-by: syzbot+da4f525235510683d855@syzkaller.appspotmail.com Fixes: f8b92ba67c5d ("mount: Add mount warning for impending timestamp expiry") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2019-09-261-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge more updates from Andrew Morton: - almost all of the rest of -mm - various other subsystems Subsystems affected by this patch series: memcg, misc, core-kernel, lib, checkpatch, reiserfs, fat, fork, cpumask, kexec, uaccess, kconfig, kgdb, bug, ipc, lzo, kasan, madvise, cleanups, pagemap * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (77 commits) arch/sparc/include/asm/pgtable_64.h: fix build mm: treewide: clarify pgtable_page_{ctor,dtor}() naming ntfs: remove (un)?likely() from IS_ERR() conditions IB/hfi1: remove unlikely() from IS_ERR*() condition xfs: remove unlikely() from WARN_ON() condition wimax/i2400m: remove unlikely() from WARN*() condition fs: remove unlikely() from WARN_ON() condition xen/events: remove unlikely() from WARN() condition checkpatch: check for nested (un)?likely() calls hexagon: drop empty and unused free_initrd_mem mm: factor out common parts between MADV_COLD and MADV_PAGEOUT mm: introduce MADV_PAGEOUT mm: change PAGEREF_RECLAIM_CLEAN with PAGE_REFRECLAIM mm: introduce MADV_COLD mm: untag user pointers in mmap/munmap/mremap/brk vfio/type1: untag user pointers in vaddr_get_pfn tee/shm: untag user pointers in tee_shm_register media/v4l2-core: untag user pointers in videobuf_dma_contig_user_get drm/radeon: untag user pointers in radeon_gem_userptr_ioctl drm/amdgpu: untag user pointers ...
| * fs/namespace: untag user pointers in copy_mount_optionsAndrey Konovalov2019-09-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a part of a series that extends kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. In copy_mount_options a user address is being subtracted from TASK_SIZE. If the address is lower than TASK_SIZE, the size is calculated to not allow the exact_copy_from_user() call to cross TASK_SIZE boundary. However if the address is tagged, then the size will be calculated incorrectly. Untag the address before subtracting. Link: http://lkml.kernel.org/r/1de225e4a54204bfd7f25dac2635e31aa4aa1d90.1563904656.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Eric Auger <eric.auger@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jens Wiklander <jens.wiklander@linaro.org> Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge tag 'fuse-update-5.4' of ↵Linus Torvalds2019-09-251-2/+0
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse Pull fuse updates from Miklos Szeredi: - Continue separating the transport (user/kernel communication) and the filesystem layers of fuse. Getting rid of most layering violations will allow for easier cleanup and optimization later on. - Prepare for the addition of the virtio-fs filesystem. The actual filesystem will be introduced by a separate pull request. - Convert to new mount API. - Various fixes, optimizations and cleanups. * tag 'fuse-update-5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: (55 commits) fuse: Make fuse_args_to_req static fuse: fix memleak in cuse_channel_open fuse: fix beyond-end-of-page access in fuse_parse_cache() fuse: unexport fuse_put_request fuse: kmemcg account fs data fuse: on 64-bit store time in d_fsdata directly fuse: fix missing unlock_page in fuse_writepage() fuse: reserve byteswapped init opcodes fuse: allow skipping control interface and forced unmount fuse: dissociate DESTROY from fuseblk fuse: delete dentry if timeout is zero fuse: separate fuse device allocation and installation in fuse_conn fuse: add fuse_iqueue_ops callbacks fuse: extract fuse_fill_super_common() fuse: export fuse_dequeue_forget() function fuse: export fuse_get_unique() fuse: export fuse_send_init_request() fuse: export fuse_len_args() fuse: export fuse_end_request() fuse: fix request limit ...
| * vfs: subtype handling moved to fuseDavid Howells2019-09-061-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The unused vfs code can be removed. Don't pass empty subtype (same as if ->parse callback isn't called). The bits that are left involve determining whether it's permitted to split the filesystem type string passed in to mount(2). Consequently, this means that we cannot get rid of the FS_HAS_SUBTYPE flag unless we define that a type string with a dot in it always indicates a subtype specification. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | Merge tag 'y2038-vfs' of ↵Linus Torvalds2019-09-191-1/+32
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground Pull y2038 vfs updates from Arnd Bergmann: "Add inode timestamp clamping. This series from Deepa Dinamani adds a per-superblock minimum/maximum timestamp limit for a file system, and clamps timestamps as they are written, to avoid random behavior from integer overflow as well as having different time stamps on disk vs in memory. At mount time, a warning is now printed for any file system that can represent current timestamps but not future timestamps more than 30 years into the future, similar to the arbitrary 30 year limit that was added to settimeofday(). This was picked as a compromise to warn users to migrate to other file systems (e.g. ext4 instead of ext3) when they need the file system to survive beyond 2038 (or similar limits in other file systems), but not get in the way of normal usage" * tag 'y2038-vfs' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground: ext4: Reduce ext4 timestamp warnings isofs: Initialize filesystem timestamp ranges pstore: fs superblock limits fs: omfs: Initialize filesystem timestamp ranges fs: hpfs: Initialize filesystem timestamp ranges fs: ceph: Initialize filesystem timestamp ranges fs: sysv: Initialize filesystem timestamp ranges fs: affs: Initialize filesystem timestamp ranges fs: fat: Initialize filesystem timestamp ranges fs: cifs: Initialize filesystem timestamp ranges fs: nfs: Initialize filesystem timestamp ranges ext4: Initialize timestamps limits 9p: Fill min and max timestamps in sb fs: Fill in max and min timestamps in superblock utimes: Clamp the timestamps before update mount: Add mount warning for impending timestamp expiry timestamp_truncate: Replace users of timespec64_trunc vfs: Add timestamp_truncate() api vfs: Add file timestamp range support
| * | mount: Add mount warning for impending timestamp expiryDeepa Dinamani2019-08-301-1/+32
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The warning reuses the uptime max of 30 years used by settimeofday(). Note that the warning is only emitted for writable filesystem mounts through the mount syscall. Automounts do not have the same warning. Print out the warning in human readable format using the struct tm. After discussion with Arnd Bergmann, we chose to print only the year number. The raw s_time_max is also displayed, and the user can easily decode it e.g. "date -u -d @$((0x7fffffff))". We did not want to consolidate struct rtc_tm and struct tm just to print the date using a format specifier as part of this series. Given that the rtc_tm is not compiled on all architectures, this is not a trivial patch. This can be added in the future. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Acked-by: Jeff Layton <jlayton@kernel.org>
* | Merge tag 'filelock-v5.4-1' of ↵Linus Torvalds2019-09-181-3/+8
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux Pull file locking updates from Jeff Layton: "Just a couple of minor bugfixes, a revision to a tracepoint to account for some earlier changes to the internals, and a patch to add a pr_warn message when someone tries to mount a filesystem with '-o mand' on a kernel that has that support disabled" * tag 'filelock-v5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux: locks: fix a memory leak bug in __break_lease() locks: print a warning when mount fails due to lack of "mand" support locks: Fix procfs output for file leases locks: revise generic_add_lease tracepoint
| * | locks: print a warning when mount fails due to lack of "mand" supportJeff Layton2019-08-161-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since 9e8925b67a ("locks: Allow disabling mandatory locking at compile time"), attempts to mount filesystems with "-o mand" will fail. Unfortunately, there is no other indiciation of the reason for the failure. Change how the function is defined for better readability. When CONFIG_MANDATORY_FILE_LOCKING is disabled, printk a warning when someone attempts to mount with -o mand. Also, add a blurb to the mandatory-locking.txt file to explain about the "mand" option, and the behavior one should expect when it is disabled. Reported-by: Jan Kara <jack@suse.cz> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jeff Layton <jlayton@kernel.org>
* | | Merge branch 'work.namei' of ↵Linus Torvalds2019-09-181-5/+5
|\ \ \ | |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs namei updates from Al Viro: "Pathwalk-related stuff" [ Audit-related cleanups, misc simplifications, and easier to follow nd->root refcounts - Linus ] * 'work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: devpts_pty_kill(): don't bother with d_delete() infiniband: don't bother with d_delete() hypfs: don't bother with d_delete() fs/namei.c: keep track of nd->root refcount status fs/namei.c: new helper - legitimize_root() kill the last users of user_{path,lpath,path_dir}() namei.h: get the comments on LOOKUP_... in sync with reality kill LOOKUP_NO_EVAL, don't bother including namei.h from audit.h audit_inode(): switch to passing AUDIT_INODE_... filename_mountpoint(): make LOOKUP_NO_EVAL unconditional there filename_lookup(): audit_inode() argument is always 0
| * | kill the last users of user_{path,lpath,path_dir}()Al Viro2019-08-301-3/+5
| | | | | | | | | | | | | | | | | | old wrappers with few callers remaining; put them out of their misery... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | filename_mountpoint(): make LOOKUP_NO_EVAL unconditional thereAl Viro2019-07-211-2/+0
| |/ | | | | | | | | | | | | | | user_path_mountpoint_at() always gets it and the reasons to have it there (i.e. in umount(2)) apply to kern_path_mountpoint() callers as well. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* / fix the struct mount leak in umount_tree()Al Viro2019-07-261-2/+2
|/ | | | | | | | | | | | | | We need to drop everything we remove from the tree, whether mnt_has_parent() is true or not. Usually the bug manifests as a slow memory leak (leaked struct mount for initramfs); it becomes much more visible in mount_subtree() users, such as btrfs. There we leak a struct mount for btrfs superblock being mounted, which prevents fs shutdown on subsequent umount. Fixes: 56cbb429d911 ("switch the remnants of releasing the mountpoint away from fs_pin") Reported-by: Nikolay Borisov <nborisov@suse.com> Tested-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'work.dcache2' of ↵Linus Torvalds2019-07-201-82/+77
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull dcache and mountpoint updates from Al Viro: "Saner handling of refcounts to mountpoints. Transfer the counting reference from struct mount ->mnt_mountpoint over to struct mountpoint ->m_dentry. That allows us to get rid of the convoluted games with ordering of mount shutdowns. The cost is in teaching shrink_dcache_{parent,for_umount} to cope with mixed-filesystem shrink lists, which we'll also need for the Slab Movable Objects patchset" * 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: switch the remnants of releasing the mountpoint away from fs_pin get rid of detach_mnt() make struct mountpoint bear the dentry reference to mountpoint, not struct mount Teach shrink_dcache_parent() to cope with mixed-filesystem shrink lists fs/namespace.c: shift put_mountpoint() to callers of unhash_mnt() __detach_mounts(): lookup_mountpoint() can't return ERR_PTR() anymore nfs: dget_parent() never returns NULL ceph: don't open-code the check for dead lockref
| * switch the remnants of releasing the mountpoint away from fs_pinAl Viro2019-07-161-18/+19
| | | | | | | | | | | | | | | | | | We used to need rather convoluted ordering trickery to guarantee that dput() of ex-mountpoints happens before the final mntput() of the same. Since we don't need that anymore, there's no point playing with fs_pin for that. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * get rid of detach_mnt()Al Viro2019-07-161-34/+28
| | | | | | | | | | | | | | | | | | Lift getting the original mount (dentry is actually not needed at all) of the mountpoint into the callers - to do_move_mount() and pivot_root() level. That simplifies the cleanup in those and allows to get saner arguments for attach_mnt_recursive(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * make struct mountpoint bear the dentry reference to mountpoint, not struct mountAl Viro2019-07-161-27/+25
| | | | | | | | | | | | | | | | | | | | | | Using dput_to_list() to shift the contributing reference from ->mnt_mountpoint to ->mnt_mp->m_dentry. Dentries are dropped (with dput_to_list()) as soon as struct mountpoint is destroyed; in cases where we are under namespace_sem we use the global list, shrinking it in namespace_unlock(). In case of detaching stuck MNT_LOCKed children at final mntput_no_expire() we use a local list and shrink it ourselves. ->mnt_ex_mountpoint crap is gone. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fs/namespace.c: shift put_mountpoint() to callers of unhash_mnt()Al Viro2019-07-041-4/+6
| | | | | | | | | | | | | | make unhash_mnt() return the mountpoint to be dropped, let callers deal with it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * __detach_mounts(): lookup_mountpoint() can't return ERR_PTR() anymoreAl Viro2019-07-041-1/+1
| | | | | | | | | | | | ... not since 1e9c75fb9c47 ("mnt: fix __detach_mounts infinite loop") Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'work.mount0' of ↵Linus Torvalds2019-07-191-8/+7
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount updates from Al Viro: "The first part of mount updates. Convert filesystems to use the new mount API" * 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) mnt_init(): call shmem_init() unconditionally constify ksys_mount() string arguments don't bother with registering rootfs init_rootfs(): don't bother with init_ramfs_fs() vfs: Convert smackfs to use the new mount API vfs: Convert selinuxfs to use the new mount API vfs: Convert securityfs to use the new mount API vfs: Convert apparmorfs to use the new mount API vfs: Convert openpromfs to use the new mount API vfs: Convert xenfs to use the new mount API vfs: Convert gadgetfs to use the new mount API vfs: Convert oprofilefs to use the new mount API vfs: Convert ibmasmfs to use the new mount API vfs: Convert qib_fs/ipathfs to use the new mount API vfs: Convert efivarfs to use the new mount API vfs: Convert configfs to use the new mount API vfs: Convert binfmt_misc to use the new mount API convenience helper: get_tree_single() convenience helper get_tree_nodev() vfs: Kill sget_userns() ...
| * mnt_init(): call shmem_init() unconditionallyAl Viro2019-07-041-0/+2
| | | | | | | | | | | | | | | | | | No point having two call sites (earlier in init_rootfs() from mnt_init() in case we are going to use shmem-style rootfs, later from do_basic_setup() unconditionally), along with the logics in shmem_init() itself to make the second call a no-op... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * constify ksys_mount() string argumentsAl Viro2019-07-041-2/+2
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * don't bother with registering rootfsAl Viro2019-07-041-6/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | init_mount_tree() can get to rootfs_fs_type directly and that simplifies a lot of things. We don't need to register it, we don't need to look it up *and* we don't need to bother with preventing subsequent userland mounts. That's the way we should've done that from the very beginning. There is a user-visible change, namely the disappearance of "rootfs" from /proc/filesystems. Note that it's been unmountable all along and it didn't show up in /proc/mounts; however, it *is* a user-visible change and theoretically some script might've been using its presence in /proc/filesystems to tell 2.4.11+ from earlier kernels. *IF* any complaints about behaviour change do show up, we could fake it in /proc/filesystems. I very much doubt we'll have to, though. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * move mount_capable() further outAl Viro2019-05-251-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Call graph of vfs_get_tree(): vfs_fsconfig_locked() # neither kernmount, nor submount do_new_mount() # neither kernmount, nor submount fc_mount() afs_mntpt_do_automount() # submount mount_one_hugetlbfs() # kernmount pid_ns_prepare_proc() # kernmount mq_create_mount() # kernmount vfs_kern_mount() simple_pin_fs() # kernmount vfs_submount() # submount kern_mount() # kernmount init_mount_tree() btrfs_mount() nfs_do_root_mount() The first two need the check (unconditionally). init_mount_tree() is setting rootfs up; any capability checks make zero sense for that one. And btrfs_mount()/ nfs_do_root_mount() have the checks already done in their callers. IOW, we can shift mount_capable() handling into the two callers - one in the normal case of mount(2), another - in fsconfig(2) handling of FSCONFIG_CMD_CREATE. I.e. the syscalls that set a new filesystem up. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | vfs: move_mount: reject moving kernel internal mountsEric Biggers2019-07-011-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sys_move_mount() crashes by dereferencing the pointer MNT_NS_INTERNAL, a.k.a. ERR_PTR(-EINVAL), if the old mount is specified by fd for a kernel object with an internal mount, such as a pipe or memfd. Fix it by checking for this case and returning -EINVAL. [AV: what we want is is_mounted(); use that instead of making the condition even more convoluted] Reproducer: #include <unistd.h> #define __NR_move_mount 429 #define MOVE_MOUNT_F_EMPTY_PATH 0x00000004 int main() { int fds[2]; pipe(fds); syscall(__NR_move_mount, fds[0], "", -1, "/", MOVE_MOUNT_F_EMPTY_PATH); } Reported-by: syzbot+6004acbaa1893ad013f0@syzkaller.appspotmail.com Fixes: 2db154b3ea8e ("vfs: syscall: Add move_mount(2) to move mounts around") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fs/namespace: fix unprivileged mount propagationChristian Brauner2019-06-171-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When propagating mounts across mount namespaces owned by different user namespaces it is not possible anymore to move or umount the mount in the less privileged mount namespace. Here is a reproducer: sudo mount -t tmpfs tmpfs /mnt sudo --make-rshared /mnt # create unprivileged user + mount namespace and preserve propagation unshare -U -m --map-root --propagation=unchanged # now change back to the original mount namespace in another terminal: sudo mkdir /mnt/aaa sudo mount -t tmpfs tmpfs /mnt/aaa # now in the unprivileged user + mount namespace mount --move /mnt/aaa /opt Unfortunately, this is a pretty big deal for userspace since this is e.g. used to inject mounts into running unprivileged containers. So this regression really needs to go away rather quickly. The problem is that a recent change falsely locked the root of the newly added mounts by setting MNT_LOCKED. Fix this by only locking the mounts on copy_mnt_ns() and not when adding a new mount. Fixes: 3bd045cc9c4b ("separate copying and locking mount tree on cross-userns copies") Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Tested-by: Christian Brauner <christian@brauner.io> Acked-by: Christian Brauner <christian@brauner.io> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Christian Brauner <christian@brauner.io> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | vfs: fsmount: add missing mntget()Eric Biggers2019-06-171-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | sys_fsmount() needs to take a reference to the new mount when adding it to the anonymous mount namespace. Otherwise the filesystem can be unmounted while it's still in use, as found by syzkaller. Reported-by: Mark Rutland <mark.rutland@arm.com> Reported-by: syzbot+99de05d099a170867f22@syzkaller.appspotmail.com Reported-by: syzbot+7008b8b8ba7df475fdc8@syzkaller.appspotmail.com Fixes: 93766fbd2696 ("vfs: syscall: Add fsmount() to create a mount for a superblock") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 209Thomas Gleixner2019-05-301-1/+1
|/ | | | | | | | | | | | | | | | | | | | Based on 1 normalized pattern(s): released under gpl v2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 15 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528171438.895196075@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* do_move_mount(): fix an unsafe use of is_anon_ns()Al Viro2019-05-091-1/+1
| | | | | | | | | | | | What triggers it is a race between mount --move and umount -l of the source; we should reject it (the source is parentless *and* not the root of anon namespace at that), but the check for namespace being an anon one is broken in that case - is_anon_ns() needs ns to be non-NULL. Better fixed here than in is_anon_ns(), since the rest of the callers is guaranteed to get a non-NULL argument... Reported-by: syzbot+494c7ddf66acac0ad747@syzkaller.appspotmail.com Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: syscall: Add fsmount() to create a mount for a superblockDavid Howells2019-03-201-3/+143
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide a system call by which a filesystem opened with fsopen() and configured by a series of fsconfig() calls can have a detached mount object created for it. This mount object can then be attached to the VFS mount hierarchy using move_mount() by passing the returned file descriptor as the from directory fd. The system call looks like: int mfd = fsmount(int fsfd, unsigned int flags, unsigned int attr_flags); where fsfd is the file descriptor returned by fsopen(). flags can be 0 or FSMOUNT_CLOEXEC. attr_flags is a bitwise-OR of the following flags: MOUNT_ATTR_RDONLY Mount read-only MOUNT_ATTR_NOSUID Ignore suid and sgid bits MOUNT_ATTR_NODEV Disallow access to device special files MOUNT_ATTR_NOEXEC Disallow program execution MOUNT_ATTR__ATIME Setting on how atime should be updated MOUNT_ATTR_RELATIME - Update atime relative to mtime/ctime MOUNT_ATTR_NOATIME - Do not update access times MOUNT_ATTR_STRICTATIME - Always perform atime updates MOUNT_ATTR_NODIRATIME Do not update directory access times In the event that fsmount() fails, it may be possible to get an error message by calling read() on fsfd. If no message is available, ENODATA will be reported. Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-api@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* teach move_mount(2) to work with OPEN_TREE_CLONEDavid Howells2019-03-201-7/+55
| | | | | | | | | | | | | | | | | | Allow a detached tree created by open_tree(..., OPEN_TREE_CLONE) to be attached by move_mount(2). If by the time of final fput() of OPEN_TREE_CLONE-opened file its tree is not detached anymore, it won't be dissolved. move_mount(2) is adjusted to handle detached source. That gives us equivalents of mount --bind and mount --rbind. Thanks also to Alan Jenkins <alan.christopher.jenkins@gmail.com> for providing a whole bunch of ways to break things using this interface. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: syscall: Add move_mount(2) to move mounts aroundDavid Howells2019-03-201-31/+95
| | | | | | | | | | | | | | | Add a move_mount() system call that will move a mount from one place to another and, in the next commit, allow to attach an unattached mount tree. The new system call looks like the following: int move_mount(int from_dfd, const char *from_path, int to_dfd, const char *to_path, unsigned int flags); Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-api@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: syscall: Add open_tree(2) to reference or clone a mountAl Viro2019-03-201-22/+135
| | | | | | | | | | | | | | | | | | | | | | | | | | | open_tree(dfd, pathname, flags) Returns an O_PATH-opened file descriptor or an error. dfd and pathname specify the location to open, in usual fashion (see e.g. fstatat(2)). flags should be an OR of some of the following: * AT_PATH_EMPTY, AT_NO_AUTOMOUNT, AT_SYMLINK_NOFOLLOW - same meanings as usual * OPEN_TREE_CLOEXEC - make the resulting descriptor close-on-exec * OPEN_TREE_CLONE or OPEN_TREE_CLONE | AT_RECURSIVE - instead of opening the location in question, create a detached mount tree matching the subtree rooted at location specified by dfd/pathname. With AT_RECURSIVE the entire subtree is cloned, without it - only the part within in the mount containing the location in question. In other words, the same as mount --rbind or mount --bind would've taken. The detached tree will be dissolved on the final close of obtained file. Creation of such detached trees requires the same capabilities as doing mount --bind. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: David Howells <dhowells@redhat.com> cc: linux-api@vger.kernel.org Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Merge branch 'work.mount' of ↵Linus Torvalds2019-03-121-149/+246
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs mount infrastructure updates from Al Viro: "The rest of core infrastructure; no new syscalls in that pile, but the old parts are switched to new infrastructure. At that point conversions of individual filesystems can happen independently; some are done here (afs, cgroup, procfs, etc.), there's also a large series outside of that pile dealing with NFS (quite a bit of option-parsing stuff is getting used there - it's one of the most convoluted filesystems in terms of mount-related logics), but NFS bits are the next cycle fodder. It got seriously simplified since the last cycle; documentation is probably the weakest bit at the moment - I considered dropping the commit introducing Documentation/filesystems/mount_api.txt (cutting the size increase by quarter ;-), but decided that it would be better to fix it up after -rc1 instead. That pile allows to do followup work in independent branches, which should make life much easier for the next cycle. fs/super.c size increase is unpleasant; there's a followup series that allows to shrink it considerably, but I decided to leave that until the next cycle" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits) afs: Use fs_context to pass parameters over automount afs: Add fs_context support vfs: Add some logging to the core users of the fs_context log vfs: Implement logging through fs_context vfs: Provide documentation for new mount API vfs: Remove kern_mount_data() hugetlbfs: Convert to fs_context cpuset: Use fs_context kernfs, sysfs, cgroup, intel_rdt: Support fs_context cgroup: store a reference to cgroup_ns into cgroup_fs_context cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper cgroup_do_mount(): massage calling conventions cgroup: stash cgroup_root reference into cgroup_fs_context cgroup2: switch to option-by-option parsing cgroup1: switch to option-by-option parsing cgroup: take options parsing into ->parse_monolithic() cgroup: fold cgroup1_mount() into cgroup1_get_tree() cgroup: start switching to fs_context ipc: Convert mqueue fs to fs_context proc: Add fs_context support to procfs ...
| * vfs: Remove kern_mount_data()David Howells2019-02-281-3/+3
| | | | | | | | | | | | | | The kern_mount_data() isn't used any more so remove it. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: Implement a filesystem superblock creation/configuration contextDavid Howells2019-02-281-16/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | [AV - unfuck kern_mount_data(); we want non-NULL ->mnt_ns on long-living mounts] [AV - reordering fs/namespace.c is badly overdue, but let's keep it separate from that series] [AV - drop simple_pin_fs() change] [AV - clean vfs_kern_mount() failure exits up] Implement a filesystem context concept to be used during superblock creation for mount and superblock reconfiguration for remount. The mounting procedure then becomes: (1) Allocate new fs_context context. (2) Configure the context. (3) Create superblock. (4) Query the superblock. (5) Create a mount for the superblock. (6) Destroy the context. Rather than calling fs_type->mount(), an fs_context struct is created and fs_type->init_fs_context() is called to set it up. Pointers exist for the filesystem and LSM to hang their private data off. A set of operations has to be set by ->init_fs_context() to provide freeing, duplication, option parsing, binary data parsing, validation, mounting and superblock filling. Legacy filesystems are supported by the provision of a set of legacy fs_context operations that build up a list of mount options and then invoke fs_type->mount() from within the fs_context ->get_tree() operation. This allows all filesystems to be accessed using fs_context. It should be noted that, whilst this patch adds a lot of lines of code, there is quite a bit of duplication with existing code that can be eliminated should all filesystems be converted over. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * convert do_remount_sb() to fs_contextDavid Howells2019-01-301-22/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replace do_remount_sb() with a function, reconfigure_super(), that's fs_context aware. The fs_context is expected to be parameterised already and have ->root pointing to the superblock to be reconfigured. A legacy wrapper is provided that is intended to be called from the fs_context ops when those appear, but for now is called directly from reconfigure_super(). This wrapper invokes the ->remount_fs() superblock op for the moment. It is intended that the remount_fs() op will be phased out. The fs_context->purpose is set to FS_CONTEXT_FOR_RECONFIGURE to indicate that the context is being used for reconfiguration. do_umount_root() is provided to consolidate remount-to-R/O for umount and emergency remount by creating a context and invoking reconfiguration. do_remount(), do_umount() and do_emergency_remount_callback() are switched to use the new process. [AV -- fold UMOUNT and EMERGENCY_REMOUNT in; fixes the umount / bug, gets rid of pointless complexity] [AV -- set ->net_ns in all cases; nfs remount will need that] [AV -- shift security_sb_remount() call into reconfigure_super(); the callers that didn't do security_sb_remount() have NULL fc->security anyway, so it's a no-op for them] Signed-off-by: David Howells <dhowells@redhat.com> Co-developed-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs_get_tree(): evict the call of security_sb_kern_mount()Al Viro2019-01-301-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Right now vfs_get_tree() calls security_sb_kern_mount() (i.e. mount MAC) unless it gets MS_KERNMOUNT or MS_SUBMOUNT in flags. Doing it that way is both clumsy and imprecise. Consider the callers' tree of vfs_get_tree(): vfs_get_tree() <- do_new_mount() <- vfs_kern_mount() <- simple_pin_fs() <- vfs_submount() <- kern_mount_data() <- init_mount_tree() <- btrfs_mount() <- vfs_get_tree() <- nfs_do_root_mount() <- nfs4_try_mount() <- nfs_fs_mount() <- vfs_get_tree() <- nfs4_referral_mount() do_new_mount() always does need MAC (we are guaranteed that neither MS_KERNMOUNT nor MS_SUBMOUNT will be passed there). simple_pin_fs(), vfs_submount() and kern_mount_data() pass explicit flags inhibiting that check. So does nfs4_referral_mount() (the flags there are ulimately coming from vfs_submount()). init_mount_tree() is called too early for anything LSM-related; it doesn't matter whether we attempt those checks, they'll do nothing. Finally, in case of btrfs_mount() and nfs_fs_mount(), doing MAC is pointless - either the caller will do it, or the flags are such that we wouldn't have done it either. In other words, the one and only case when we want that check done is when we are called from do_new_mount(), and there we want it unconditionally. So let's simply move it there. The superblock is still locked, so nobody is going to get access to it (via ustat(2), etc.) until we get a chance to apply the checks - we are free to move them to any point up to where we drop ->s_umount (in do_new_mount_fc()). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * new helper: do_new_mount_fc()David Howells2019-01-301-26/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create an fs_context-aware version of do_new_mount(). This takes an fs_context with a superblock already attached to it. Make do_new_mount() use do_new_mount_fc() rather than do_new_mount(); this allows the consolidation of the mount creation, check and add steps. To make this work, mount_too_revealing() is changed to take a superblock rather than a mount (which the fs_context doesn't have available), allowing this check to be done before the mount object is created. Signed-off-by: David Howells <dhowells@redhat.com> Co-developed-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * teach vfs_get_tree() to handle subtype, switch do_new_mount() to itAl Viro2019-01-301-31/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Roll the handling of subtypes into do_new_mount() and vfs_get_tree(). The former determines any subtype string and hangs it off the fs_context; the latter applies it. Make do_new_mount() create, parameterise and commit an fs_context and create a mount for itself rather than calling vfs_kern_mount(). [AV -- missing kstrdup()] [AV -- ... and no kstrdup() if we get to setting ->s_submount - we simply transfer it from fc, leaving NULL behind] [AV -- constify ->s_submount, while we are at it] Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * new helpers: vfs_create_mount(), fc_mount()Al Viro2019-01-301-24/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create a new helper, vfs_create_mount(), that creates a detached vfsmount object from an fs_context that has a superblock attached to it. Almost all uses will be paired with immediately preceding vfs_get_tree(); add a helper for such combination. Switch vfs_kern_mount() to use this. NOTE: mild behaviour change; passing NULL as 'device name' to something like procfs will change /proc/*/mountstats - "device none" instead on "no device". That is consistent with /proc/mounts et.al. [do'h - EXPORT_SYMBOL_GPL slipped in by mistake; removed] [AV -- remove confused comment from vfs_create_mount()] [AV -- removed the second argument] Reviewed-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * vfs: Introduce fs_context, switch vfs_kern_mount() to it.David Howells2019-01-301-14/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a filesystem context concept to be used during superblock creation for mount and superblock reconfiguration for remount. This is allocated at the beginning of the mount procedure and into it is placed: (1) Filesystem type. (2) Namespaces. (3) Source/Device names (there may be multiple). (4) Superblock flags (SB_*). (5) Security details. (6) Filesystem-specific data, as set by the mount options. Accessor functions are then provided to set up a context, parameterise it from monolithic mount data (the data page passed to mount(2)) and tear it down again. A legacy wrapper is provided that implements what will be the basic operations, wrapping access to filesystems that aren't yet aware of the fs_context. Finally, vfs_kern_mount() is changed to make use of the fs_context and mount_fs() is replaced by vfs_get_tree(), called from vfs_kern_mount(). [AV -- add missing kstrdup()] [AV -- put_cred() can be unconditional - fc->cred can't be NULL] [AV -- take legacy_validate() contents into legacy_parse_monolithic()] [AV -- merge KERNEL_MOUNT and USER_MOUNT] [AV -- don't unlock superblock on success return from vfs_get_tree()] [AV -- kill 'reference' argument of init_fs_context()] Signed-off-by: David Howells <dhowells@redhat.com> Co-developed-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * saner handling of temporary namespacesAl Viro2019-01-301-39/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | mount_subtree() creates (and soon destroys) a temporary namespace, so that automounts could function normally. These beasts should never become anyone's current namespaces; they don't, but it would be better to make prevention of that more straightforward. And since they don't become anyone's current namespace, we don't need to bother with reserving procfs inums for those. Teach alloc_mnt_ns() to skip inum allocation if told so, adjust put_mnt_ns() accordingly, make mount_subtree() use temporary (anon) namespace. is_anon_ns() checks if a namespace is such. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * separate copying and locking mount tree on cross-userns copiesAl Viro2019-01-301-22/+37
| | | | | | | | | | | | | | Rather than having propagate_mnt() check doing unprivileged copies, lock them before commit_tree(). Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge tag 'audit-pr-20190305' of ↵Linus Torvalds2019-03-071-0/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit Pull audit updates from Paul Moore: "A lucky 13 audit patches for v5.1. Despite the rather large diffstat, most of the changes are from two bug fix patches that move code from one Kconfig option to another. Beyond that bit of churn, the remaining changes are largely cleanups and bug-fixes as we slowly march towards container auditing. It isn't all boring though, we do have a couple of new things: file capabilities v3 support, and expanded support for filtering on filesystems to solve problems with remote filesystems. All changes pass the audit-testsuite. Please merge for v5.1" * tag 'audit-pr-20190305' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit: audit: mark expected switch fall-through audit: hide auditsc_get_stamp and audit_serial prototypes audit: join tty records to their syscall audit: remove audit_context when CONFIG_ AUDIT and not AUDITSYSCALL audit: remove unused actx param from audit_rule_match audit: ignore fcaps on umount audit: clean up AUDITSYSCALL prototypes and stubs audit: more filter PATH records keyed on filesystem magic audit: add support for fcaps v3 audit: move loginuid and sessionid from CONFIG_AUDITSYSCALL to CONFIG_AUDIT audit: add syscall information to CONFIG_CHANGE records audit: hand taken context to audit_kill_trees for syscall logging audit: give a clue what CONFIG_CHANGE op was involved
| * | audit: ignore fcaps on umountRichard Guy Briggs2019-01-301-0/+2
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Don't fetch fcaps when umount2 is called to avoid a process hang while it waits for the missing resource to (possibly never) re-appear. Note the comment above user_path_mountpoint_at(): * A umount is a special case for path walking. We're not actually interested * in the inode in this situation, and ESTALE errors can be a problem. We * simply want track down the dentry and vfsmount attached at the mountpoint * and avoid revalidating the last component. This can happen on ceph, cifs, 9p, lustre, fuse (gluster) or NFS. Please see the github issue tracker https://github.com/linux-audit/audit-kernel/issues/100 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> [PM: merge fuzz in audit_log_fcaps()] Signed-off-by: Paul Moore <paul@paul-moore.com>
* | Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds2019-03-041-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull vfs fixes from Al Viro: "Assorted fixes that sat in -next for a while, all over the place" * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: aio: Fix locking in aio_poll() exec: Fix mem leak in kernel_read_file copy_mount_string: Limit string length to PATH_MAX cgroup: saner refcounting for cgroup_root fix cgroup_do_mount() handling of failure exits
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