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2022-11-29fsverity: simplify fsverity_get_digest()Eric Biggers
Instead of looking up the algorithm by name in hash_algo_name[] to get its hash_algo ID, just store the hash_algo ID in the fsverity_hash_alg struct. Verify at boot time that every fsverity_hash_alg has a valid hash_algo ID with matching digest size. Remove an unnecessary memset() of the whole digest array to 0 before the digest is copied into it. Finally, remove the pr_debug statement. There is already a pr_debug for the fsverity digest when the file is opened. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Link: https://lore.kernel.org/r/20221129045139.69803-1-ebiggers@kernel.org
2022-11-28fsverity: stop using PG_error to track error statusEric Biggers
As a step towards freeing the PG_error flag for other uses, change ext4 and f2fs to stop using PG_error to track verity errors. Instead, if a verity error occurs, just mark the whole bio as failed. The coarser granularity isn't really a problem since it isn't any worse than what the block layer provides, and errors from a multi-page readahead aren't reported to applications unless a single-page read fails too. f2fs supports compression, which makes the f2fs changes a bit more complicated than desired, but the basic premise still works. Note: there are still a few uses of PageError in f2fs, but they are on the write path, so they are unrelated and this patch doesn't touch them. Reviewed-by: Chao Yu <chao@kernel.org> Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20221129070401.156114-1-ebiggers@kernel.org
2022-10-06Merge tag 'for-6.1-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs updates from David Sterba: "There's a bunch of performance improvements, most notably the FIEMAP speedup, the new block group tree to speed up mount on large filesystems, more io_uring integration, some sysfs exports and the usual fixes and core updates. Summary: Performance: - outstanding FIEMAP speed improvement - algorithmic change how extents are enumerated leads to orders of magnitude speed boost (uncached and cached) - extent sharing check speedup (2.2x uncached, 3x cached) - add more cancellation points, allowing to interrupt seeking in files with large number of extents - more efficient hole and data seeking (4x uncached, 1.3x cached) - sample results: 256M, 32K extents: 4s -> 29ms (~150x) 512M, 64K extents: 30s -> 59ms (~550x) 1G, 128K extents: 225s -> 120ms (~1800x) - improved inode logging, especially for directories (on dbench workload throughput +25%, max latency -21%) - improved buffered IO, remove redundant extent state tracking, lowering memory consumption and avoiding rb tree traversal - add sysfs tunable to let qgroup temporarily skip exact accounting when deleting snapshot, leading to a speedup but requiring a rescan after that, will be used by snapper - support io_uring and buffered writes, until now it was just for direct IO, with the no-wait semantics implemented in the buffered write path it now works and leads to speed improvement in IOPS (2x), throughput (2.2x), latency (depends, 2x to 150x) - small performance improvements when dropping and searching for extent maps as well as when flushing delalloc in COW mode (throughput +5MB/s) User visible changes: - new incompatible feature block-group-tree adding a dedicated tree for tracking block groups, this allows a much faster load during mount and avoids seeking unlike when it's scattered in the extent tree items - this reduces mount time for many-terabyte sized filesystems - conversion tool will be provided so existing filesystem can also be updated in place - to reduce test matrix and feature combinations requires no-holes and free-space-tree (mkfs defaults since 5.15) - improved reporting of super block corruption detected by scrub - scrub also tries to repair super block and does not wait until next commit - discard stats and tunables are exported in sysfs (/sys/fs/btrfs/FSID/discard) - qgroup status is exported in sysfs (/sys/sys/fs/btrfs/FSID/qgroups/) - verify that super block was not modified when thawing filesystem Fixes: - FIEMAP fixes - fix extent sharing status, does not depend on the cached status where merged - flush delalloc so compressed extents are reported correctly - fix alignment of VMA for memory mapped files on THP - send: fix failures when processing inodes with no links (orphan files and directories) - fix race between quota enable and quota rescan ioctl - handle more corner cases for read-only compat feature verification - fix missed extent on fsync after dropping extent maps Core: - lockdep annotations to validate various transactions states and state transitions - preliminary support for fs-verity in send - more effective memory use in scrub for subpage where sector is smaller than page - block group caching progress logic has been removed, load is now synchronous - simplify end IO callbacks and bio handling, use chained bios instead of own tracking - add no-wait semantics to several functions (tree search, nocow, flushing, buffered write - cleanups and refactoring MM changes: - export balance_dirty_pages_ratelimited_flags" * tag 'for-6.1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (177 commits) btrfs: set generation before calling btrfs_clean_tree_block in btrfs_init_new_buffer btrfs: drop extent map range more efficiently btrfs: avoid pointless extent map tree search when flushing delalloc btrfs: remove unnecessary next extent map search btrfs: remove unnecessary NULL pointer checks when searching extent maps btrfs: assert tree is locked when clearing extent map from logging btrfs: remove unnecessary extent map initializations btrfs: remove the refcount warning/check at free_extent_map() btrfs: add helper to replace extent map range with a new extent map btrfs: move open coded extent map tree deletion out of inode eviction btrfs: use cond_resched_rwlock_write() during inode eviction btrfs: use extent_map_end() at btrfs_drop_extent_map_range() btrfs: move btrfs_drop_extent_cache() to extent_map.c btrfs: fix missed extent on fsync after dropping extent maps btrfs: remove stale prototype of btrfs_write_inode btrfs: enable nowait async buffered writes btrfs: assert nowait mode is not used for some btree search functions btrfs: make btrfs_buffered_write nowait compatible btrfs: plumb NOWAIT through the write path btrfs: make lock_and_cleanup_extent_if_need nowait compatible ...
2022-09-26btrfs: send: add support for fs-verityBoris Burkov
Preserve the fs-verity status of a btrfs file across send/recv. There is no facility for installing the Merkle tree contents directly on the receiving filesystem, so we package up the parameters used to enable verity found in the verity descriptor. This gives the receive side enough information to properly enable verity again. Note that this means that receive will have to re-compute the whole Merkle tree, similar to how compression worked before encoded_write. Since the file becomes read-only after verity is enabled, it is important that verity is added to the send stream after any file writes. Therefore, when we process a verity item, merely note that it happened, then actually create the command in the send stream during 'finish_inode_if_needed'. This also creates V3 of the send stream format, without any format changes besides adding the new commands and attributes. Signed-off-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2022-08-19fs-verity: use kmap_local_page() instead of kmap()Eric Biggers
Convert the use of kmap() to its recommended replacement kmap_local_page(). This avoids the overhead of doing a non-local mapping, which is unnecessary in this case. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Link: https://lore.kernel.org/r/20220818224010.43778-1-ebiggers@kernel.org
2022-08-19fs-verity: use memcpy_from_page()Eric Biggers
Replace extract_hash() with the memcpy_from_page() helper function. This is simpler, and it has the side effect of replacing the use of kmap_atomic() with its recommended replacement kmap_local_page(). Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Link: https://lore.kernel.org/r/20220818223903.43710-1-ebiggers@kernel.org
2022-07-15fs-verity: mention btrfs supportEric Biggers
btrfs supports fs-verity since Linux v5.15. Document this. Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: David Sterba <dsterba@suse.com> Link: https://lore.kernel.org/r/20220610000616.18225-1-ebiggers@kernel.org
2022-05-24Merge tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecacheLinus Torvalds
Pull page cache updates from Matthew Wilcox: - Appoint myself page cache maintainer - Fix how scsicam uses the page cache - Use the memalloc_nofs_save() API to replace AOP_FLAG_NOFS - Remove the AOP flags entirely - Remove pagecache_write_begin() and pagecache_write_end() - Documentation updates - Convert several address_space operations to use folios: - is_dirty_writeback - readpage becomes read_folio - releasepage becomes release_folio - freepage becomes free_folio - Change filler_t to require a struct file pointer be the first argument like ->read_folio * tag 'folio-5.19' of git://git.infradead.org/users/willy/pagecache: (107 commits) nilfs2: Fix some kernel-doc comments Appoint myself page cache maintainer fs: Remove aops->freepage secretmem: Convert to free_folio nfs: Convert to free_folio orangefs: Convert to free_folio fs: Add free_folio address space operation fs: Convert drop_buffers() to use a folio fs: Change try_to_free_buffers() to take a folio jbd2: Convert release_buffer_page() to use a folio jbd2: Convert jbd2_journal_try_to_free_buffers to take a folio reiserfs: Convert release_buffer_page() to use a folio fs: Remove last vestiges of releasepage ubifs: Convert to release_folio reiserfs: Convert to release_folio orangefs: Convert to release_folio ocfs2: Convert to release_folio nilfs2: Remove comment about releasepage nfs: Convert to release_folio jfs: Convert to release_folio ...
2022-05-24Merge tag 'integrity-v5.19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity Pull IMA updates from Mimi Zohar: "New is IMA support for including fs-verity file digests and signatures in the IMA measurement list as well as verifying the fs-verity file digest based signatures, both based on policy. In addition, are two bug fixes: - avoid reading UEFI variables, which cause a page fault, on Apple Macs with T2 chips. - remove the original "ima" template Kconfig option to address a boot command line ordering issue. The rest is a mixture of code/documentation cleanup" * tag 'integrity-v5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity: integrity: Fix sparse warnings in keyring_handler evm: Clean up some variables evm: Return INTEGRITY_PASS for enum integrity_status value '0' efi: Do not import certificates from UEFI Secure Boot for T2 Macs fsverity: update the documentation ima: support fs-verity file digest based version 3 signatures ima: permit fsverity's file digests in the IMA measurement list ima: define a new template field named 'd-ngv2' and templates fs-verity: define a function to return the integrity protected file digest ima: use IMA default hash algorithm for integrity violations ima: fix 'd-ng' comments and documentation ima: remove the IMA_TEMPLATE Kconfig option ima: remove redundant initialization of pointer 'file'.
2022-05-19fs-verity: Use struct_size() helper in enable_verity()Zhang Jianhua
Follow the best practice for allocating a variable-sized structure. Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com> [ebiggers: adjusted commit message] Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20220519022450.2434483-1-chris.zjh@huawei.com
2022-05-18fs-verity: remove unused parameter desc_size in fsverity_create_info()Zhang Jianhua
The parameter desc_size in fsverity_create_info() is useless and it is not referenced anywhere. The greatest meaning of desc_size here is to indecate the size of struct fsverity_descriptor and futher calculate the size of signature. However, the desc->sig_size can do it also and it is indeed, so remove it. Therefore, it is no need to acquire desc_size by fsverity_get_descriptor() in ensure_verity_info(), so remove the parameter desc_ret in fsverity_get_descriptor() too. Signed-off-by: Zhang Jianhua <chris.zjh@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Link: https://lore.kernel.org/r/20220518132256.2297655-1-chris.zjh@huawei.com
2022-05-08mm/readahead: Convert page_cache_async_readahead to take a folioMatthew Wilcox (Oracle)
Removes a couple of calls to compound_head and saves a few bytes. Also convert verity's read_file_data_page() to be folio-based. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2022-05-01fs-verity: define a function to return the integrity protected file digestMimi Zohar
Define a function named fsverity_get_digest() to return the verity file digest and the associated hash algorithm (enum hash_algo). This assumes that before calling fsverity_get_digest() the file must have been opened, which is even true for the IMA measure/appraise on file open policy rule use case (func=FILE_CHECK). do_open() calls vfs_open() immediately prior to ima_file_check(). Acked-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-04-01fs: Remove ->readpages address space operationMatthew Wilcox (Oracle)
All filesystems have now been converted to use ->readahead, so remove the ->readpages operation and fix all the comments that used to refer to it. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Al Viro <viro@zeniv.linux.org.uk>
2021-09-22fs-verity: fix signed integer overflow with i_size near S64_MAXEric Biggers
If the file size is almost S64_MAX, the calculated number of Merkle tree levels exceeds FS_VERITY_MAX_LEVELS, causing FS_IOC_ENABLE_VERITY to fail. This is unintentional, since as the comment above the definition of FS_VERITY_MAX_LEVELS states, it is enough for over U64_MAX bytes of data using SHA-256 and 4K blocks. (Specifically, 4096*128**8 >= 2**64.) The bug is actually that when the number of blocks in the first level is calculated from i_size, there is a signed integer overflow due to i_size being signed. Fix this by treating i_size as unsigned. This was found by the new test "generic: test fs-verity EFBIG scenarios" (https://lkml.kernel.org/r/b1d116cd4d0ea74b9cd86f349c672021e005a75c.1631558495.git.boris@bur.io). This didn't affect ext4 or f2fs since those have a smaller maximum file size, but it did affect btrfs which allows files up to S64_MAX bytes. Reported-by: Boris Burkov <boris@bur.io> Fixes: 3fda4c617e84 ("fs-verity: implement FS_IOC_ENABLE_VERITY ioctl") Fixes: fd2d1acfcadf ("fs-verity: add the hook for file ->open()") Cc: <stable@vger.kernel.org> # v5.4+ Reviewed-by: Boris Burkov <boris@bur.io> Link: https://lore.kernel.org/r/20210916203424.113376-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2021-04-22fsverity: relax build time dependency on CRYPTO_SHA256Ard Biesheuvel
CONFIG_CRYPTO_SHA256 denotes the generic C implementation of the SHA-256 shash algorithm, which is selected as the default crypto shash provider for fsverity. However, fsverity has no strict link time dependency, and the same shash could be exposed by an optimized implementation, and arm64 has a number of those (scalar, NEON-based and one based on special crypto instructions). In such cases, it makes little sense to require that the generic C implementation is incorporated as well, given that it will never be called. To address this, relax the 'select' clause to 'imply' so that the generic driver can be omitted from the build if desired. Acked-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-02-23Merge tag 'idmapped-mounts-v5.12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux Pull idmapped mounts from Christian Brauner: "This introduces idmapped mounts which has been in the making for some time. Simply put, different mounts can expose the same file or directory with different ownership. This initial implementation comes with ports for fat, ext4 and with Christoph's port for xfs with more filesystems being actively worked on by independent people and maintainers. Idmapping mounts handle a wide range of long standing use-cases. Here are just a few: - Idmapped mounts make it possible to easily share files between multiple users or multiple machines especially in complex scenarios. For example, idmapped mounts will be used in the implementation of portable home directories in systemd-homed.service(8) where they allow users to move their home directory to an external storage device and use it on multiple computers where they are assigned different uids and gids. This effectively makes it possible to assign random uids and gids at login time. - It is possible to share files from the host with unprivileged containers without having to change ownership permanently through chown(2). - It is possible to idmap a container's rootfs and without having to mangle every file. For example, Chromebooks use it to share the user's Download folder with their unprivileged containers in their Linux subsystem. - It is possible to share files between containers with non-overlapping idmappings. - Filesystem that lack a proper concept of ownership such as fat can use idmapped mounts to implement discretionary access (DAC) permission checking. - They allow users to efficiently changing ownership on a per-mount basis without having to (recursively) chown(2) all files. In contrast to chown (2) changing ownership of large sets of files is instantenous with idmapped mounts. This is especially useful when ownership of a whole root filesystem of a virtual machine or container is changed. With idmapped mounts a single syscall mount_setattr syscall will be sufficient to change the ownership of all files. - Idmapped mounts always take the current ownership into account as idmappings specify what a given uid or gid is supposed to be mapped to. This contrasts with the chown(2) syscall which cannot by itself take the current ownership of the files it changes into account. It simply changes the ownership to the specified uid and gid. This is especially problematic when recursively chown(2)ing a large set of files which is commong with the aforementioned portable home directory and container and vm scenario. - Idmapped mounts allow to change ownership locally, restricting it to specific mounts, and temporarily as the ownership changes only apply as long as the mount exists. Several userspace projects have either already put up patches and pull-requests for this feature or will do so should you decide to pull this: - systemd: In a wide variety of scenarios but especially right away in their implementation of portable home directories. https://systemd.io/HOME_DIRECTORY/ - container runtimes: containerd, runC, LXD:To share data between host and unprivileged containers, unprivileged and privileged containers, etc. The pull request for idmapped mounts support in containerd, the default Kubernetes runtime is already up for quite a while now: https://github.com/containerd/containerd/pull/4734 - The virtio-fs developers and several users have expressed interest in using this feature with virtual machines once virtio-fs is ported. - ChromeOS: Sharing host-directories with unprivileged containers. I've tightly synced with all those projects and all of those listed here have also expressed their need/desire for this feature on the mailing list. For more info on how people use this there's a bunch of talks about this too. Here's just two recent ones: https://www.cncf.io/wp-content/uploads/2020/12/Rootless-Containers-in-Gitpod.pdf https://fosdem.org/2021/schedule/event/containers_idmap/ This comes with an extensive xfstests suite covering both ext4 and xfs: https://git.kernel.org/brauner/xfstests-dev/h/idmapped_mounts It covers truncation, creation, opening, xattrs, vfscaps, setid execution, setgid inheritance and more both with idmapped and non-idmapped mounts. It already helped to discover an unrelated xfs setgid inheritance bug which has since been fixed in mainline. It will be sent for inclusion with the xfstests project should you decide to merge this. In order to support per-mount idmappings vfsmounts are marked with user namespaces. The idmapping of the user namespace will be used to map the ids of vfs objects when they are accessed through that mount. By default all vfsmounts are marked with the initial user namespace. The initial user namespace is used to indicate that a mount is not idmapped. All operations behave as before and this is verified in the testsuite. Based on prior discussions we want to attach the whole user namespace and not just a dedicated idmapping struct. This allows us to reuse all the helpers that already exist for dealing with idmappings instead of introducing a whole new range of helpers. In addition, if we decide in the future that we are confident enough to enable unprivileged users to setup idmapped mounts the permission checking can take into account whether the caller is privileged in the user namespace the mount is currently marked with. The user namespace the mount will be marked with can be specified by passing a file descriptor refering to the user namespace as an argument to the new mount_setattr() syscall together with the new MOUNT_ATTR_IDMAP flag. The system call follows the openat2() pattern of extensibility. The following conditions must be met in order to create an idmapped mount: - The caller must currently have the CAP_SYS_ADMIN capability in the user namespace the underlying filesystem has been mounted in. - The underlying filesystem must support idmapped mounts. - The mount must not already be idmapped. This also implies that the idmapping of a mount cannot be altered once it has been idmapped. - The mount must be a detached/anonymous mount, i.e. it must have been created by calling open_tree() with the OPEN_TREE_CLONE flag and it must not already have been visible in the filesystem. The last two points guarantee easier semantics for userspace and the kernel and make the implementation significantly simpler. By default vfsmounts are marked with the initial user namespace and no behavioral or performance changes are observed. The manpage with a detailed description can be found here: https://git.kernel.org/brauner/man-pages/c/1d7b902e2875a1ff342e036a9f866a995640aea8 In order to support idmapped mounts, filesystems need to be changed and mark themselves with the FS_ALLOW_IDMAP flag in fs_flags. The patches to convert individual filesystem are not very large or complicated overall as can be seen from the included fat, ext4, and xfs ports. Patches for other filesystems are actively worked on and will be sent out separately. The xfstestsuite can be used to verify that port has been done correctly. The mount_setattr() syscall is motivated independent of the idmapped mounts patches and it's been around since July 2019. One of the most valuable features of the new mount api is the ability to perform mounts based on file descriptors only. Together with the lookup restrictions available in the openat2() RESOLVE_* flag namespace which we added in v5.6 this is the first time we are close to hardened and race-free (e.g. symlinks) mounting and path resolution. While userspace has started porting to the new mount api to mount proper filesystems and create new bind-mounts it is currently not possible to change mount options of an already existing bind mount in the new mount api since the mount_setattr() syscall is missing. With the addition of the mount_setattr() syscall we remove this last restriction and userspace can now fully port to the new mount api, covering every use-case the old mount api could. We also add the crucial ability to recursively change mount options for a whole mount tree, both removing and adding mount options at the same time. This syscall has been requested multiple times by various people and projects. There is a simple tool available at https://github.com/brauner/mount-idmapped that allows to create idmapped mounts so people can play with this patch series. I'll add support for the regular mount binary should you decide to pull this in the following weeks: Here's an example to a simple idmapped mount of another user's home directory: u1001@f2-vm:/$ sudo ./mount --idmap both:1000:1001:1 /home/ubuntu/ /mnt u1001@f2-vm:/$ ls -al /home/ubuntu/ total 28 drwxr-xr-x 2 ubuntu ubuntu 4096 Oct 28 22:07 . drwxr-xr-x 4 root root 4096 Oct 28 04:00 .. -rw------- 1 ubuntu ubuntu 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 ubuntu ubuntu 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 ubuntu ubuntu 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 ubuntu ubuntu 807 Feb 25 2020 .profile -rw-r--r-- 1 ubuntu ubuntu 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 ubuntu ubuntu 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ ls -al /mnt/ total 28 drwxr-xr-x 2 u1001 u1001 4096 Oct 28 22:07 . drwxr-xr-x 29 root root 4096 Oct 28 22:01 .. -rw------- 1 u1001 u1001 3154 Oct 28 22:12 .bash_history -rw-r--r-- 1 u1001 u1001 220 Feb 25 2020 .bash_logout -rw-r--r-- 1 u1001 u1001 3771 Feb 25 2020 .bashrc -rw-r--r-- 1 u1001 u1001 807 Feb 25 2020 .profile -rw-r--r-- 1 u1001 u1001 0 Oct 16 16:11 .sudo_as_admin_successful -rw------- 1 u1001 u1001 1144 Oct 28 00:43 .viminfo u1001@f2-vm:/$ touch /mnt/my-file u1001@f2-vm:/$ setfacl -m u:1001:rwx /mnt/my-file u1001@f2-vm:/$ sudo setcap -n 1001 cap_net_raw+ep /mnt/my-file u1001@f2-vm:/$ ls -al /mnt/my-file -rw-rwxr--+ 1 u1001 u1001 0 Oct 28 22:14 /mnt/my-file u1001@f2-vm:/$ ls -al /home/ubuntu/my-file -rw-rwxr--+ 1 ubuntu ubuntu 0 Oct 28 22:14 /home/ubuntu/my-file u1001@f2-vm:/$ getfacl /mnt/my-file getfacl: Removing leading '/' from absolute path names # file: mnt/my-file # owner: u1001 # group: u1001 user::rw- user:u1001:rwx group::rw- mask::rwx other::r-- u1001@f2-vm:/$ getfacl /home/ubuntu/my-file getfacl: Removing leading '/' from absolute path names # file: home/ubuntu/my-file # owner: ubuntu # group: ubuntu user::rw- user:ubuntu:rwx group::rw- mask::rwx other::r--" * tag 'idmapped-mounts-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: (41 commits) xfs: remove the possibly unused mp variable in xfs_file_compat_ioctl xfs: support idmapped mounts ext4: support idmapped mounts fat: handle idmapped mounts tests: add mount_setattr() selftests fs: introduce MOUNT_ATTR_IDMAP fs: add mount_setattr() fs: add attr_flags_to_mnt_flags helper fs: split out functions to hold writers namespace: only take read lock in do_reconfigure_mnt() mount: make {lock,unlock}_mount_hash() static namespace: take lock_mount_hash() directly when changing flags nfs: do not export idmapped mounts overlayfs: do not mount on top of idmapped mounts ecryptfs: do not mount on top of idmapped mounts ima: handle idmapped mounts apparmor: handle idmapped mounts fs: make helpers idmap mount aware exec: handle idmapped mounts would_dump: handle idmapped mounts ...
2021-02-07fs-verity: support reading signature with ioctlEric Biggers
Add support for FS_VERITY_METADATA_TYPE_SIGNATURE to FS_IOC_READ_VERITY_METADATA. This allows a userspace server program to retrieve the built-in signature (if present) of a verity file for serving to a client which implements fs-verity compatible verification. See the patch which introduced FS_IOC_READ_VERITY_METADATA for more details. The ability for userspace to read the built-in signatures is also useful because it allows a system that is using the in-kernel signature verification to migrate to userspace signature verification. This has been tested using a new xfstest which calls this ioctl via a new subcommand for the 'fsverity' program from fsverity-utils. Link: https://lore.kernel.org/r/20210115181819.34732-7-ebiggers@kernel.org Reviewed-by: Victor Hsieh <victorhsieh@google.com> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
2021-02-07fs-verity: support reading descriptor with ioctlEric Biggers
Add support for FS_VERITY_METADATA_TYPE_DESCRIPTOR to FS_IOC_READ_VERITY_METADATA. This allows a userspace server program to retrieve the fs-verity descriptor of a file for serving to a client which implements fs-verity compatible verification. See the patch which introduced FS_IOC_READ_VERITY_METADATA for more details. "fs-verity descriptor" here means only the part that userspace cares about because it is hashed to produce the file digest. It doesn't include the signature which ext4 and f2fs append to the fsverity_descriptor struct when storing it on-disk, since that way of storing the signature is an implementation detail. The next patch adds a separate metadata_type value for retrieving the signature separately. This has been tested using a new xfstest which calls this ioctl via a new subcommand for the 'fsverity' program from fsverity-utils. Link: https://lore.kernel.org/r/20210115181819.34732-6-ebiggers@kernel.org Reviewed-by: Victor Hsieh <victorhsieh@google.com> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
2021-02-07fs-verity: support reading Merkle tree with ioctlEric Biggers
Add support for FS_VERITY_METADATA_TYPE_MERKLE_TREE to FS_IOC_READ_VERITY_METADATA. This allows a userspace server program to retrieve the Merkle tree of a verity file for serving to a client which implements fs-verity compatible verification. See the patch which introduced FS_IOC_READ_VERITY_METADATA for more details. This has been tested using a new xfstest which calls this ioctl via a new subcommand for the 'fsverity' program from fsverity-utils. Link: https://lore.kernel.org/r/20210115181819.34732-5-ebiggers@kernel.org Reviewed-by: Victor Hsieh <victorhsieh@google.com> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
2021-02-07fs-verity: add FS_IOC_READ_VERITY_METADATA ioctlEric Biggers
Add an ioctl FS_IOC_READ_VERITY_METADATA which will allow reading verity metadata from a file that has fs-verity enabled, including: - The Merkle tree - The fsverity_descriptor (not including the signature if present) - The built-in signature, if present This ioctl has similar semantics to pread(). It is passed the type of metadata to read (one of the above three), and a buffer, offset, and size. It returns the number of bytes read or an error. Separate patches will add support for each of the above metadata types. This patch just adds the ioctl itself. This ioctl doesn't make any assumption about where the metadata is stored on-disk. It does assume the metadata is in a stable format, but that's basically already the case: - The Merkle tree and fsverity_descriptor are defined by how fs-verity file digests are computed; see the "File digest computation" section of Documentation/filesystems/fsverity.rst. Technically, the way in which the levels of the tree are ordered relative to each other wasn't previously specified, but it's logical to put the root level first. - The built-in signature is the value passed to FS_IOC_ENABLE_VERITY. This ioctl is useful because it allows writing a server program that takes a verity file and serves it to a client program, such that the client can do its own fs-verity compatible verification of the file. This only makes sense if the client doesn't trust the server and if the server needs to provide the storage for the client. More concretely, there is interest in using this ability in Android to export APK files (which are protected by fs-verity) to "protected VMs". This would use Protected KVM (https://lwn.net/Articles/836693), which provides an isolated execution environment without having to trust the traditional "host". A "guest" VM can boot from a signed image and perform specific tasks in a minimum trusted environment using files that have fs-verity enabled on the host, without trusting the host or requiring that the guest has its own trusted storage. Technically, it would be possible to duplicate the metadata and store it in separate files for serving. However, that would be less efficient and would require extra care in userspace to maintain file consistency. In addition to the above, the ability to read the built-in signatures is useful because it allows a system that is using the in-kernel signature verification to migrate to userspace signature verification. Link: https://lore.kernel.org/r/20210115181819.34732-4-ebiggers@kernel.org Reviewed-by: Victor Hsieh <victorhsieh@google.com> Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
2021-02-07fs-verity: don't pass whole descriptor to fsverity_verify_signature()Eric Biggers
Now that fsverity_get_descriptor() validates the sig_size field, fsverity_verify_signature() doesn't need to do it. Just change the prototype of fsverity_verify_signature() to take the signature directly rather than take a fsverity_descriptor. Link: https://lore.kernel.org/r/20210115181819.34732-3-ebiggers@kernel.org Reviewed-by: Victor Hsieh <victorhsieh@google.com> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Reviewed-by: Amy Parker <enbyamy@gmail.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
2021-02-07fs-verity: factor out fsverity_get_descriptor()Eric Biggers
The FS_IOC_READ_VERITY_METADATA ioctl will need to return the fs-verity descriptor (and signature) to userspace. There are a few ways we could implement this: - Save a copy of the descriptor (and signature) in the fsverity_info struct that hangs off of the in-memory inode. However, this would waste memory since most of the time it wouldn't be needed. - Regenerate the descriptor from the merkle_tree_params in the fsverity_info. However, this wouldn't work for the signature, nor for the salt which the merkle_tree_params only contains indirectly as part of the 'hashstate'. It would also be error-prone. - Just get them from the filesystem again. The disadvantage is that in general we can't trust that they haven't been maliciously changed since the file has opened. However, the use cases for FS_IOC_READ_VERITY_METADATA don't require that it verifies the chain of trust. So this is okay as long as we do some basic validation. In preparation for implementing the third option, factor out a helper function fsverity_get_descriptor() which gets the descriptor (and appended signature) from the filesystem and does some basic validation. As part of this, start checking the sig_size field for overflow. Currently fsverity_verify_signature() does this. But the new ioctl will need this too, so do it earlier. Link: https://lore.kernel.org/r/20210115181819.34732-2-ebiggers@kernel.org Reviewed-by: Victor Hsieh <victorhsieh@google.com> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Eric Biggers <ebiggers@google.com>
2021-01-24fs: add file and path permissions helpersChristian Brauner
Add two simple helpers to check permissions on a file and path respectively and convert over some callers. It simplifies quite a few codepaths and also reduces the churn in later patches quite a bit. Christoph also correctly points out that this makes codepaths (e.g. ioctls) way easier to follow that would otherwise have to do more complex argument passing than necessary. Link: https://lore.kernel.org/r/20210121131959.646623-4-christian.brauner@ubuntu.com Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jamorris@linux.microsoft.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
2020-12-14Merge branch 'linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto updates from Herbert Xu: "API: - Add speed testing on 1420-byte blocks for networking Algorithms: - Improve performance of chacha on ARM for network packets - Improve performance of aegis128 on ARM for network packets Drivers: - Add support for Keem Bay OCS AES/SM4 - Add support for QAT 4xxx devices - Enable crypto-engine retry mechanism in caam - Enable support for crypto engine on sdm845 in qce - Add HiSilicon PRNG driver support" * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (161 commits) crypto: qat - add capability detection logic in qat_4xxx crypto: qat - add AES-XTS support for QAT GEN4 devices crypto: qat - add AES-CTR support for QAT GEN4 devices crypto: atmel-i2c - select CONFIG_BITREVERSE crypto: hisilicon/trng - replace atomic_add_return() crypto: keembay - Add support for Keem Bay OCS AES/SM4 dt-bindings: Add Keem Bay OCS AES bindings crypto: aegis128 - avoid spurious references crypto_aegis128_update_simd crypto: seed - remove trailing semicolon in macro definition crypto: x86/poly1305 - Use TEST %reg,%reg instead of CMP $0,%reg crypto: x86/sha512 - Use TEST %reg,%reg instead of CMP $0,%reg crypto: aesni - Use TEST %reg,%reg instead of CMP $0,%reg crypto: cpt - Fix sparse warnings in cptpf hwrng: ks-sa - Add dependency on IOMEM and OF crypto: lib/blake2s - Move selftest prototype into header file crypto: arm/aes-ce - work around Cortex-A57/A72 silion errata crypto: ecdh - avoid unaligned accesses in ecdh_set_secret() crypto: ccree - rework cache parameters handling crypto: cavium - Use dma_set_mask_and_coherent to simplify code crypto: marvell/octeontx - Use dma_set_mask_and_coherent to simplify code ...
2020-11-23fs-verity: move structs needed for file signing to UAPI headerEric Biggers
Although it isn't used directly by the ioctls, "struct fsverity_descriptor" is required by userspace programs that need to compute fs-verity file digests in a standalone way. Therefore it's also needed to sign files in a standalone way. Similarly, "struct fsverity_formatted_digest" (previously called "struct fsverity_signed_digest" which was misleading) is also needed to sign files if the built-in signature verification is being used. Therefore, move these structs to the UAPI header. While doing this, try to make it clear that the signature-related fields in fsverity_descriptor aren't used in the file digest computation. Acked-by: Luca Boccassi <luca.boccassi@microsoft.com> Link: https://lore.kernel.org/r/20201113211918.71883-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-11-20crypto: sha - split sha.h into sha1.h and sha2.hEric Biggers
Currently <crypto/sha.h> contains declarations for both SHA-1 and SHA-2, and <crypto/sha3.h> contains declarations for SHA-3. This organization is inconsistent, but more importantly SHA-1 is no longer considered to be cryptographically secure. So to the extent possible, SHA-1 shouldn't be grouped together with any of the other SHA versions, and usage of it should be phased out. Therefore, split <crypto/sha.h> into two headers <crypto/sha1.h> and <crypto/sha2.h>, and make everyone explicitly specify whether they want the declarations for SHA-1, SHA-2, or both. This avoids making the SHA-1 declarations visible to files that don't want anything to do with SHA-1. It also prepares for potentially moving sha1.h into a new insecure/ or dangerous/ directory. Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Acked-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-11-16fs-verity: rename "file measurement" to "file digest"Eric Biggers
I originally chose the name "file measurement" to refer to the fs-verity file digest to avoid confusion with traditional full-file digests or with the bare root hash of the Merkle tree. But the name "file measurement" hasn't caught on, and usually people are calling it something else, usually the "file digest". E.g. see "struct fsverity_digest" and "struct fsverity_formatted_digest", the libfsverity_compute_digest() and libfsverity_sign_digest() functions in libfsverity, and the "fsverity digest" command. Having multiple names for the same thing is always confusing. So to hopefully avoid confusion in the future, rename "fs-verity file measurement" to "fs-verity file digest". This leaves FS_IOC_MEASURE_VERITY as the only reference to "measure" in the kernel, which makes some amount of sense since the ioctl is actively "measuring" the file. I'll be renaming this in fsverity-utils too (though similarly the 'fsverity measure' command, which is a wrapper for FS_IOC_MEASURE_VERITY, will stay). Acked-by: Luca Boccassi <luca.boccassi@microsoft.com> Link: https://lore.kernel.org/r/20201113211918.71883-4-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-11-16fs-verity: rename fsverity_signed_digest to fsverity_formatted_digestEric Biggers
The name "struct fsverity_signed_digest" is causing confusion because it isn't actually a signed digest, but rather it's the way that the digest is formatted in order to be signed. Rename it to "struct fsverity_formatted_digest" to prevent this confusion. Also update the struct's comment to clarify that it's specific to the built-in signature verification support and isn't a requirement for all fs-verity users. I'll be renaming this struct in fsverity-utils too. Acked-by: Luca Boccassi <luca.boccassi@microsoft.com> Link: https://lore.kernel.org/r/20201113211918.71883-3-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-11-16fs-verity: remove filenames from file commentsEric Biggers
Embedding the file path inside kernel source code files isn't particularly useful as often files are moved around and the paths become incorrect. checkpatch.pl warns about this since v5.10-rc1. Acked-by: Luca Boccassi <luca.boccassi@microsoft.com> Link: https://lore.kernel.org/r/20201113211918.71883-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-07-21fs-verity: use smp_load_acquire() for ->i_verity_infoEric Biggers
Normally smp_store_release() or cmpxchg_release() is paired with smp_load_acquire(). Sometimes smp_load_acquire() can be replaced with the more lightweight READ_ONCE(). However, for this to be safe, all the published memory must only be accessed in a way that involves the pointer itself. This may not be the case if allocating the object also involves initializing a static or global variable, for example. fsverity_info::tree_params.hash_alg->tfm is a crypto_ahash object that's internal to and is allocated by the crypto subsystem. So by using READ_ONCE() for ->i_verity_info, we're relying on internal implementation details of the crypto subsystem. Remove this fragile assumption by using smp_load_acquire() instead. Also fix the cmpxchg logic to correctly execute an ACQUIRE barrier when losing the cmpxchg race, since cmpxchg doesn't guarantee a memory barrier on failure. (Note: I haven't seen any real-world problems here. This change is just fixing the code to be guaranteed correct and less fragile.) Fixes: fd2d1acfcadf ("fs-verity: add the hook for file ->open()") Link: https://lore.kernel.org/r/20200721225920.114347-6-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-12fs-verity: remove unnecessary extern keywordsEric Biggers
Remove the unnecessary 'extern' keywords from function declarations. This makes it so that we don't have a mix of both styles, so it won't be ambiguous what to use in new fs-verity patches. This also makes the code shorter and matches the 'checkpatch --strict' expectation. Link: https://lore.kernel.org/r/20200511192118.71427-3-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-05-12fs-verity: fix all kerneldoc warningsEric Biggers
Fix all kerneldoc warnings in fs/verity/ and include/linux/fsverity.h. Most of these were due to missing documentation for function parameters. Detected with: scripts/kernel-doc -v -none fs/verity/*.{c,h} include/linux/fsverity.h This cleanup makes it possible to check new patches for kerneldoc warnings without having to filter out all the existing ones. Link: https://lore.kernel.org/r/20200511192118.71427-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-14fs-verity: use u64_to_user_ptr()Eric Biggers
<linux/kernel.h> already provides a macro u64_to_user_ptr(). Use it instead of open-coding the two casts. No change in behavior. Link: https://lore.kernel.org/r/20191231175408.20524-1-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-14fs-verity: use mempool for hash requestsEric Biggers
When initializing an fs-verity hash algorithm, also initialize a mempool that contains a single preallocated hash request object. Then replace the direct calls to ahash_request_alloc() and ahash_request_free() with allocating and freeing from this mempool. This eliminates the possibility of the allocation failing, which is desirable for the I/O path. This doesn't cause deadlocks because there's no case where multiple hash requests are needed at a time to make forward progress. Link: https://lore.kernel.org/r/20191231175545.20709-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-14fs-verity: implement readahead of Merkle tree pagesEric Biggers
When fs-verity verifies data pages, currently it reads each Merkle tree page synchronously using read_mapping_page(). Therefore, when the Merkle tree pages aren't already cached, fs-verity causes an extra 4 KiB I/O request for every 512 KiB of data (assuming that the Merkle tree uses SHA-256 and 4 KiB blocks). This results in more I/O requests and performance loss than is strictly necessary. Therefore, implement readahead of the Merkle tree pages. For simplicity, we take advantage of the fact that the kernel already does readahead of the file's *data*, just like it does for any other file. Due to this, we don't really need a separate readahead state (struct file_ra_state) just for the Merkle tree, but rather we just need to piggy-back on the existing data readahead requests. We also only really need to bother with the first level of the Merkle tree, since the usual fan-out factor is 128, so normally over 99% of Merkle tree I/O requests are for the first level. Therefore, make fsverity_verify_bio() enable readahead of the first Merkle tree level, for up to 1/4 the number of pages in the bio, when it sees that the REQ_RAHEAD flag is set on the bio. The readahead size is then passed down to ->read_merkle_tree_page() for the filesystem to (optionally) implement if it sees that the requested page is uncached. While we're at it, also make build_merkle_tree_level() set the Merkle tree readahead size, since it's easy to do there. However, for now don't set the readahead size in fsverity_verify_page(), since currently it's only used to verify holes on ext4 and f2fs, and it would need parameters added to know how much to read ahead. This patch significantly improves fs-verity sequential read performance. Some quick benchmarks with 'cat'-ing a 250MB file after dropping caches: On an ARM64 phone (using sha256-ce): Before: 217 MB/s After: 263 MB/s (compare to sha256sum of non-verity file: 357 MB/s) In an x86_64 VM (using sha256-avx2): Before: 173 MB/s After: 215 MB/s (compare to sha256sum of non-verity file: 223 MB/s) Link: https://lore.kernel.org/r/20200106205533.137005-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2020-01-14fs-verity: implement readahead for FS_IOC_ENABLE_VERITYEric Biggers
When it builds the first level of the Merkle tree, FS_IOC_ENABLE_VERITY sequentially reads each page of the file using read_mapping_page(). This works fine if the file's data is already in pagecache, which should normally be the case, since this ioctl is normally used immediately after writing out the file. But in any other case this implementation performs very poorly, since only one page is read at a time. Fix this by implementing readahead using the functions from mm/readahead.c. This improves performance in the uncached case by about 20x, as seen in the following benchmarks done on a 250MB file (on x86_64 with SHA-NI): FS_IOC_ENABLE_VERITY uncached (before) 3.299s FS_IOC_ENABLE_VERITY uncached (after) 0.160s FS_IOC_ENABLE_VERITY cached 0.147s sha256sum uncached 0.191s sha256sum cached 0.145s Note: we could instead switch to kernel_read(). But that would mean we'd no longer be hashing the data directly from the pagecache, which is a nice optimization of its own. And using kernel_read() would require allocating another temporary buffer, hashing the data and tree pages separately, and explicitly zero-padding the last page -- so it wouldn't really be any simpler than direct pagecache access, at least for now. Link: https://lore.kernel.org/r/20200106205410.136707-1-ebiggers@kernel.org Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-12-09treewide: Use sizeof_field() macroPankaj Bharadiya
Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except at places where these are defined. Later patches will remove the unused definition of FIELD_SIZEOF(). This patch is generated using following script: EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h" git grep -l -e "\bFIELD_SIZEOF\b" | while read file; do if [[ "$file" =~ $EXCLUDE_FILES ]]; then continue fi sed -i -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file; done Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: David Miller <davem@davemloft.net> # for net
2019-08-12fs-verity: support builtin file signaturesEric Biggers
To meet some users' needs, add optional support for having fs-verity handle a portion of the authentication policy in the kernel. An ".fs-verity" keyring is created to which X.509 certificates can be added; then a sysctl 'fs.verity.require_signatures' can be set to cause the kernel to enforce that all fs-verity files contain a signature of their file measurement by a key in this keyring. See the "Built-in signature verification" section of Documentation/filesystems/fsverity.rst for the full documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-08-12fs-verity: add SHA-512 supportEric Biggers
Add SHA-512 support to fs-verity. This is primarily a demonstration of the trivial changes needed to support a new hash algorithm in fs-verity; most users will still use SHA-256, due to the smaller space required to store the hashes. But some users may prefer SHA-512. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-08-12fs-verity: implement FS_IOC_MEASURE_VERITY ioctlEric Biggers
Add a function for filesystems to call to implement the FS_IOC_MEASURE_VERITY ioctl. This ioctl retrieves the file measurement that fs-verity calculated for the given file and is enforcing for reads; i.e., reads that don't match this hash will fail. This ioctl can be used for authentication or logging of file measurements in userspace. See the "FS_IOC_MEASURE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-08-12fs-verity: implement FS_IOC_ENABLE_VERITY ioctlEric Biggers
Add a function for filesystems to call to implement the FS_IOC_ENABLE_VERITY ioctl. This ioctl enables fs-verity on a file. See the "FS_IOC_ENABLE_VERITY" section of Documentation/filesystems/fsverity.rst for the documentation. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-28fs-verity: add data verification hooks for ->readpages()Eric Biggers
Add functions that verify data pages that have been read from a fs-verity file, against that file's Merkle tree. These will be called from filesystems' ->readpage() and ->readpages() methods. Since data verification can block, a workqueue is provided for these methods to enqueue verification work from their bio completion callback. See the "Verifying data" section of Documentation/filesystems/fsverity.rst for more information. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-28fs-verity: add the hook for file ->setattr()Eric Biggers
Add a function fsverity_prepare_setattr() which filesystems that support fs-verity must call to deny truncates of verity files. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-28fs-verity: add the hook for file ->open()Eric Biggers
Add the fsverity_file_open() function, which prepares an fs-verity file to be read from. If not already done, it loads the fs-verity descriptor from the filesystem and sets up an fsverity_info structure for the inode which describes the Merkle tree and contains the file measurement. It also denies all attempts to open verity files for writing. This commit also begins the include/linux/fsverity.h header, which declares the interface between fs/verity/ and filesystems. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>
2019-07-28fs-verity: add Kconfig and the helper functions for hashingEric Biggers
Add the beginnings of the fs/verity/ support layer, including the Kconfig option and various helper functions for hashing. To start, only SHA-256 is supported, but other hash algorithms can easily be added. Reviewed-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com>