user/sven/linux.git/include/uapi/linux/magic.h, branch v5.4.193

/dev/mem: Revoke mappings when a driver claims the region

2020-06-24T15:50:35Z

[ Upstream commit 3234ac664a870e6ea69ae3a57d824cd7edbeacc5 ] Close the hole of holding a mapping over kernel driver takeover event of a given address range. Commit 90a545e98126 ("restrict /dev/mem to idle io memory ranges") introduced CONFIG_IO_STRICT_DEVMEM with the goal of protecting the kernel against scenarios where a /dev/mem user tramples memory that a kernel driver owns. However, this protection only prevents *new* read(), write() and mmap() requests. Established mappings prior to the driver calling request_mem_region() are left alone. Especially with persistent memory, and the core kernel metadata that is stored there, there are plentiful scenarios for a /dev/mem user to violate the expectations of the driver and cause amplified damage. Teach request_mem_region() to find and shoot down active /dev/mem mappings that it believes it has successfully claimed for the exclusive use of the driver. Effectively a driver call to request_mem_region() becomes a hole-punch on the /dev/mem device. The typical usage of unmap_mapping_range() is part of truncate_pagecache() to punch a hole in a file, but in this case the implementation is only doing the "first half" of a hole punch. Namely it is just evacuating current established mappings of the "hole", and it relies on the fact that /dev/mem establishes mappings in terms of absolute physical address offsets. Once existing mmap users are invalidated they can attempt to re-establish the mapping, or attempt to continue issuing read(2) / write(2) to the invalidated extent, but they will then be subject to the CONFIG_IO_STRICT_DEVMEM checking that can block those subsequent accesses. Cc: Arnd Bergmann Cc: Ingo Molnar Cc: Kees Cook Cc: Matthew Wilcox Cc: Russell King Cc: Andrew Morton Cc: Greg Kroah-Hartman Fixes: 90a545e98126 ("restrict /dev/mem to idle io memory ranges") Signed-off-by: Dan Williams Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/159009507306.847224.8502634072429766747.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

erofs: move erofs out of staging

2019-08-24T12:20:10Z

EROFS filesystem has been merged into linux-staging for a year. EROFS is designed to be a better solution of saving extra storage space with guaranteed end-to-end performance for read-only files with the help of reduced metadata, fixed-sized output compression and decompression inplace technologies. In the past year, EROFS was greatly improved by many people as a staging driver, self-tested, betaed by a large number of our internal users, successfully applied to almost all in-service HUAWEI smartphones as the part of EMUI 9.1 and proven to be stable enough to be moved out of staging. EROFS is a self-contained filesystem driver. Although there are still some TODOs to be more generic, we have a dedicated team actively keeping on working on EROFS in order to make it better with the evolution of Linux kernel as the other in-kernel filesystems. As Pavel suggested, it's better to do as one commit since git can do moves and all histories will be saved in this way. Let's promote it from staging and enhance it more actively as a "real" part of kernel for more wider scenarios! Cc: Greg Kroah-Hartman Cc: Alexander Viro Cc: Andrew Morton Cc: Stephen Rothwell Cc: Theodore Ts'o Cc: Pavel Machek Cc: David Sterba Cc: Amir Goldstein Cc: Christoph Hellwig Cc: Darrick J . Wong Cc: Dave Chinner Cc: Jaegeuk Kim Cc: Jan Kara Cc: Richard Weinberger Cc: Linus Torvalds Cc: Chao Yu Cc: Miao Xie Cc: Li Guifu Cc: Fang Wei Signed-off-by: Gao Xiang Link: https://lore.kernel.org/r/20190822213659.5501-1-hsiangkao@aol.com Signed-off-by: Greg Kroah-Hartman

Merge branch 'work.mount0' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2019-07-19T17:42:02Z

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() ...

dma-buf: give each buffer a full-fledged inode

2019-06-14T09:30:50Z

By traversing /proc/*/fd and /proc/*/map_files, processes with CAP_ADMIN can get a lot of fine-grained data about how shmem buffers are shared among processes. stat(2) on each entry gives the caller a unique ID (st_ino), the buffer's size (st_size), and even the number of pages currently charged to the buffer (st_blocks / 512). In contrast, all dma-bufs share the same anonymous inode. So while we can count how many dma-buf fds or mappings a process has, we can't get the size of the backing buffers or tell if two entries point to the same dma-buf. On systems with debugfs, we can get a per-buffer breakdown of size and reference count, but can't tell which processes are actually holding the references to each buffer. Replace the singleton inode with full-fledged inodes allocated by alloc_anon_inode(). This involves creating and mounting a mini-pseudo-filesystem for dma-buf, following the example in fs/aio.c. Signed-off-by: Greg Hackmann Signed-off-by: Chenbo Feng Signed-off-by: Sumit Semwal Link: https://patchwork.freedesktop.org/patch/msgid/20190613223408.139221-2-fengc@google.com

zsfold: Convert zsfold to use the new mount API

2019-05-25T22:06:01Z

Convert the zsfold filesystem to the new internal mount API as the old one will be obsoleted and removed. This allows greater flexibility in communication of mount parameters between userspace, the VFS and the filesystem. See Documentation/filesystems/mount_api.txt for more information. Signed-off-by: David Howells

binder: implement binderfs

2018-12-19T08:40:13Z

As discussed at Linux Plumbers Conference 2018 in Vancouver [1] this is the implementation of binderfs. /* Abstract */ binderfs is a backwards-compatible filesystem for Android's binder ipc mechanism. Each ipc namespace will mount a new binderfs instance. Mounting binderfs multiple times at different locations in the same ipc namespace will not cause a new super block to be allocated and hence it will be the same filesystem instance. Each new binderfs mount will have its own set of binder devices only visible in the ipc namespace it has been mounted in. All devices in a new binderfs mount will follow the scheme binder%d and numbering will always start at 0. /* Backwards compatibility */ Devices requested in the Kconfig via CONFIG_ANDROID_BINDER_DEVICES for the initial ipc namespace will work as before. They will be registered via misc_register() and appear in the devtmpfs mount. Specifically, the standard devices binder, hwbinder, and vndbinder will all appear in their standard locations in /dev. Mounting or unmounting the binderfs mount in the initial ipc namespace will have no effect on these devices, i.e. they will neither show up in the binderfs mount nor will they disappear when the binderfs mount is gone. /* binder-control */ Each new binderfs instance comes with a binder-control device. No other devices will be present at first. The binder-control device can be used to dynamically allocate binder devices. All requests operate on the binderfs mount the binder-control device resides in. Assuming a new instance of binderfs has been mounted at /dev/binderfs via mount -t binderfs binderfs /dev/binderfs. Then a request to create a new binder device can be made as illustrated in [2]. Binderfs devices can simply be removed via unlink(). /* Implementation details */ - dynamic major number allocation: When binderfs is registered as a new filesystem it will dynamically allocate a new major number. The allocated major number will be returned in struct binderfs_device when a new binder device is allocated. - global minor number tracking: Minor are tracked in a global idr struct that is capped at BINDERFS_MAX_MINOR. The minor number tracker is protected by a global mutex. This is the only point of contention between binderfs mounts. - struct binderfs_info: Each binderfs super block has its own struct binderfs_info that tracks specific details about a binderfs instance: - ipc namespace - dentry of the binder-control device - root uid and root gid of the user namespace the binderfs instance was mounted in - mountable by user namespace root: binderfs can be mounted by user namespace root in a non-initial user namespace. The devices will be owned by user namespace root. - binderfs binder devices without misc infrastructure: New binder devices associated with a binderfs mount do not use the full misc_register() infrastructure. The misc_register() infrastructure can only create new devices in the host's devtmpfs mount. binderfs does however only make devices appear under its own mountpoint and thus allocates new character device nodes from the inode of the root dentry of the super block. This will have the side-effect that binderfs specific device nodes do not appear in sysfs. This behavior is similar to devpts allocated pts devices and has no effect on the functionality of the ipc mechanism itself. [1]: https://goo.gl/JL2tfX [2]: program to allocate a new binderfs binder device: #define _GNU_SOURCE #include #include #include #include #include #include #include #include #include #include int main(int argc, char *argv[]) { int fd, ret, saved_errno; size_t len; struct binderfs_device device = { 0 }; if (argc < 2) exit(EXIT_FAILURE); len = strlen(argv[1]); if (len > BINDERFS_MAX_NAME) exit(EXIT_FAILURE); memcpy(device.name, argv[1], len); fd = open("/dev/binderfs/binder-control", O_RDONLY | O_CLOEXEC); if (fd < 0) { printf("%s - Failed to open binder-control device\n", strerror(errno)); exit(EXIT_FAILURE); } ret = ioctl(fd, BINDER_CTL_ADD, &device); saved_errno = errno; close(fd); errno = saved_errno; if (ret < 0) { printf("%s - Failed to allocate new binder device\n", strerror(errno)); exit(EXIT_FAILURE); } printf("Allocated new binder device with major %d, minor %d, and " "name %s\n", device.major, device.minor, device.name); exit(EXIT_SUCCESS); } Cc: Martijn Coenen Cc: Greg Kroah-Hartman Signed-off-by: Christian Brauner Acked-by: Todd Kjos Signed-off-by: Greg Kroah-Hartman

xfs: add a define for statfs magic to uapi

2018-10-18T06:20:19Z

Needed by userspace programs that call fstatfs(). It'd be natural to publish XFS_SB_MAGIC in uapi, but while these two have identical values, they have different semantic meaning: one is an enum cookie meant for statfs, the other a signature of the on-disk format. Signed-off-by: Adam Borowski Reviewed-by: Darrick J. Wong Signed-off-by: Dave Chinner

afs: Lay the groundwork for supporting network namespaces

2017-11-13T15:38:16Z

Lay the groundwork for supporting network namespaces (netns) to the AFS filesystem by moving various global features to a network-namespace struct (afs_net) and providing an instance of this as a temporary global variable that everything uses via accessor functions for the moment. The following changes have been made: (1) Store the netns in the superblock info. This will be obtained from the mounter's nsproxy on a manual mount and inherited from the parent superblock on an automount. (2) The cell list is made per-netns. It can be viewed through /proc/net/afs/cells and also be modified by writing commands to that file. (3) The local workstation cell is set per-ns in /proc/net/afs/rootcell. This is unset by default. (4) The 'rootcell' module parameter, which sets a cell and VL server list modifies the init net namespace, thereby allowing an AFS root fs to be theoretically used. (5) The volume location lists and the file lock manager are made per-netns. (6) The AF_RXRPC socket and associated I/O bits are made per-ns. The various workqueues remain global for the moment. Changes still to be made: (1) /proc/fs/afs/ should be moved to /proc/net/afs/ and a symlink emplaced from the old name. (2) A per-netns subsys needs to be registered for AFS into which it can store its per-netns data. (3) Rather than the AF_RXRPC socket being opened on module init, it needs to be opened on the creation of a superblock in that netns. (4) The socket needs to be closed when the last superblock using it is destroyed and all outstanding client calls on it have been completed. This prevents a reference loop on the namespace. (5) It is possible that several namespaces will want to use AFS, in which case each one will need its own UDP port. These can either be set through /proc/net/afs/cm_port or the kernel can pick one at random. The init_ns gets 7001 by default. Other issues that need resolving: (1) The DNS keyring needs net-namespacing. (2) Where do upcalls go (eg. DNS request-key upcall)? (3) Need something like open_socket_in_file_ns() syscall so that AFS command line tools attempting to operate on an AFS file/volume have their RPC calls go to the right place. Signed-off-by: David Howells

License cleanup: add SPDX license identifier to uapi header files with no license

2017-11-02T10:19:54Z

Many user space API headers are missing licensing information, which makes it hard for compliance tools to determine the correct license. By default are files without license information under the default license of the kernel, which is GPLV2. Marking them GPLV2 would exclude them from being included in non GPLV2 code, which is obviously not intended. The user space API headers fall under the syscall exception which is in the kernels COPYING file: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". otherwise syscall usage would not be possible. Update the files which contain no license information with an SPDX license identifier. The chosen identifier is 'GPL-2.0 WITH Linux-syscall-note' which is the officially assigned identifier for the Linux syscall exception. SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

ocfs2: use magic.h

2017-07-06T23:24:30Z

Filesystems generally use SUPER_MAGIC values from magic.h instead of a local definition. Link: http://lkml.kernel.org/r/20170521154217.27917-1-fabf@skynet.be Signed-off-by: Fabian Frederick Reviewed-by: Mark Fasheh Cc: Joel Becker Cc: Junxiao Bi Cc: Joseph Qi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds