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path: root/fs/overlayfs/copy_up.c
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2017-06-28ovl: copy-up: don't unlock between lookup and linkMiklos Szeredi
Nothing prevents mischief on upper layer while we are busy copying up the data. Move the lookup right before the looked up dentry is actually used. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 01ad3eb8a073 ("ovl: concurrent copy up of regular files") Cc: <stable@vger.kernel.org> # v4.11
2017-06-05overlayfs: use uuid_t instead of uuid_beChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2017-06-05fs: switch ->s_uuid to uuid_tChristoph Hellwig
For some file systems we still memcpy into it, but in various places this already allows us to use the proper uuid helpers. More to come.. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> (Changes to IMA/EVM) Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
2017-05-29ovl: mark upper merge dir with type origin entries "impure"Amir Goldstein
An upper dir is marked "impure" to let ovl_iterate() know that this directory may contain non pure upper entries whose d_ino may need to be read from the origin inode. We already mark a non-merge dir "impure" when moving a non-pure child entry inside it, to let ovl_iterate() know not to iterate the non-merge dir directly. Mark also a merge dir "impure" when moving a non-pure child entry inside it and when copying up a child entry inside it. This can be used to optimize ovl_iterate() to perform a "pure merge" of upper and lower directories, merging the content of the directories, without having to read d_ino from origin inodes. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-19ovl: remove unused arg from ovl_lookup_temp()Miklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-18ovl: don't fail copy-up if upper doesn't support xattrMiklos Szeredi
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-18ovl: fix creds leak in copy up error pathAmir Goldstein
Fixes: 42f269b92540 ("ovl: rearrange code in ovl_copy_up_locked()") Cc: <stable@vger.kernel.org> # v4.11 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-05-05ovl: store file handle of lower inode on copy upAmir Goldstein
Sometimes it is interesting to know if an upper file is pure upper or a copy up target, and if it is a copy up target, it may be interesting to find the copy up origin. This will be used to preserve lower inode numbers across copy up. Store the lower inode file handle in upper inode extended attribute overlay.origin on copy up to use it later for these cases. Store the lower filesystem uuid along side the file handle, so we can validate that we are looking for the origin file in the original fs. If lower fs does not support NFS export ops store a zero sized xattr so we can always use the overlay.origin xattr to distinguish between a copy up and a pure upper inode. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-03-03Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "Because copy up can take a long time, serialized copy ups could be a big performance bottleneck. This update allows concurrent copy up of regular files eliminating this potential problem. There are also minor fixes" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: drop CAP_SYS_RESOURCE from saved mounter's credentials ovl: properly implement sync_filesystem() ovl: concurrent copy up of regular files ovl: introduce copy up waitqueue ovl: copy up regular file using O_TMPFILE ovl: rearrange code in ovl_copy_up_locked() ovl: check if upperdir fs supports O_TMPFILE
2017-03-03Merge branch 'rebased-statx' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs 'statx()' update from Al Viro. This adds the new extended stat() interface that internally subsumes our previous stat interfaces, and allows user mode to specify in more detail what kind of information it wants. It also allows for some explicit synchronization information to be passed to the filesystem, which can be relevant for network filesystems: is the cached value ok, or do you need open/close consistency, or what? From David Howells. Andreas Dilger points out that the first version of the extended statx interface was posted June 29, 2010: https://www.spinics.net/lists/linux-fsdevel/msg33831.html * 'rebased-statx' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: statx: Add a system call to make enhanced file info available
2017-03-02statx: Add a system call to make enhanced file info availableDavid Howells
Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-02sched/headers: Prepare to move signal wakeup & sigpending methods from ↵Ingo Molnar
<linux/sched.h> into <linux/sched/signal.h> Fix up affected files that include this signal functionality via sched.h. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h>Ingo Molnar
Add #include <linux/cred.h> dependencies to all .c files rely on sched.h doing that for them. Note that even if the count where we need to add extra headers seems high, it's still a net win, because <linux/sched.h> is included in over 2,200 files ... Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-07ovl: concurrent copy up of regular filesAmir Goldstein
Now that copy up of regular file is done using O_TMPFILE, we don't need to hold rename_lock throughout copy up. Use the copy up waitqueue to synchronize concurrent copy up of the same file. Different regular files can be copied up concurrently. The upper dir inode_lock is taken instead of rename_lock, because it is needed for lookup and later for linking the temp file, but it is released while copying up data. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-07ovl: copy up regular file using O_TMPFILEAmir Goldstein
In preparation for concurrent copy up, implement copy up of regular file as O_TMPFILE that is linked to upperdir instead of a file in workdir that is moved to upperdir. Suggested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2017-02-07ovl: rearrange code in ovl_copy_up_locked()Amir Goldstein
As preparation to implementing copy up with O_TMPFILE, name the variable for dentry before final rename 'temp' and assign it to 'newdentry' only after rename. Also lookup upper dentry before looking up temp dentry and move ovl_set_timestamps() into ovl_copy_up_locked(), because that is going to be more convenient for upcoming change. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This update contains: - try to clone on copy-up - allow renaming a directory - split source into managable chunks - misc cleanups and fixes It does not contain the read-only fd data inconsistency fix, which Al didn't like. I'll leave that to the next year..." * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (36 commits) ovl: fix reStructuredText syntax errors in documentation ovl: fix return value of ovl_fill_super ovl: clean up kstat usage ovl: fold ovl_copy_up_truncate() into ovl_copy_up() ovl: create directories inside merged parent opaque ovl: opaque cleanup ovl: show redirect_dir mount option ovl: allow setting max size of redirect ovl: allow redirect_dir to default to "on" ovl: check for emptiness of redirect dir ovl: redirect on rename-dir ovl: lookup redirects ovl: consolidate lookup for underlying layers ovl: fix nested overlayfs mount ovl: check namelen ovl: split super.c ovl: use d_is_dir() ovl: simplify lookup ovl: check lower existence of rename target ovl: rename: simplify handling of lower/merged directory ...
2016-12-16ovl: clean up kstat usageAl Viro
FWIW, there's a bit of abuse of struct kstat in overlayfs object creation paths - for one thing, it ends up with a very small subset of struct kstat (mode + rdev), for another it also needs link in case of symlinks and ends up passing it separately. IMO it would be better to introduce a separate object for that. In principle, we might even lift that thing into general API and switch ->mkdir()/->mknod()/->symlink() to identical calling conventions. Hell knows, perhaps ->create() as well... Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: fold ovl_copy_up_truncate() into ovl_copy_up()Amir Goldstein
This removes code duplication. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: opaque cleanupMiklos Szeredi
oe->opaque is set for a) whiteouts b) directories having the "trusted.overlay.opaque" xattr Case b can be simplified, since setting the xattr always implies setting oe->opaque. Also once set, the opaque flag is never cleared. Don't need to set opaque flag for non-directories. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: redirect on rename-dirMiklos Szeredi
Current code returns EXDEV when a directory would need to be copied up to move. We could copy up the directory tree in this case, but there's another, simpler solution: point to old lower directory from moved upper directory. This is achieved with a "trusted.overlay.redirect" xattr storing the path relative to the root of the overlay. After such attribute has been set, the directory can be moved without further actions required. This is a backward incompatible feature, old kernels won't be able to correctly mount an overlay containing redirected directories. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-16ovl: use vfs_clone_file_range() for copy up if possibleAmir Goldstein
When copying up within the same fs, try to use vfs_clone_file_range(). This is very efficient when lower and upper are on the same fs with file reflink support. If vfs_clone_file_range() fails for any reason, copy up falls back to the regular data copy code. Tested correct behavior when lower and upper are on: 1. same ext4 (copy) 2. same xfs + reflink patches + mkfs.xfs (copy) 3. same xfs + reflink patches + mkfs.xfs -m reflink=1 (reflink) 4. different xfs + reflink patches + mkfs.xfs -m reflink=1 (copy) For comparison, on my laptop, xfstest overlay/001 (copy up of large sparse files) takes less than 1 second in the xfs reflink setup vs. 25 seconds on the rest of the setups. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-12-04don't open-code file_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-10-31ovl: fsync after copy-upMiklos Szeredi
Make sure the copied up file hits the disk before renaming to the final destination. If this is not done then the copy-up may corrupt the data in the file in case of a crash. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org>
2016-10-14Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This update contains fixes to the "use mounter's permission to access underlying layers" area, and miscellaneous other fixes and cleanups. No new features this time" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: use vfs_get_link() vfs: add vfs_get_link() helper ovl: use generic_readlink ovl: explain error values when removing acl from workdir ovl: Fix info leak in ovl_lookup_temp() ovl: during copy up, switch to mounter's creds early ovl: lookup: do getxattr with mounter's permission ovl: copy_up_xattr(): use strnlen
2016-10-14ovl: use vfs_get_link()Miklos Szeredi
Resulting in a complete removal of a function basically implementing the inverse of vfs_readlink(). As a bonus, now the proper security hook is also called. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-10-10Merge branch 'work.xattr' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs xattr updates from Al Viro: "xattr stuff from Andreas This completes the switch to xattr_handler ->get()/->set() from ->getxattr/->setxattr/->removexattr" * 'work.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: vfs: Remove {get,set,remove}xattr inode operations xattr: Stop calling {get,set,remove}xattr inode operations vfs: Check for the IOP_XATTR flag in listxattr xattr: Add __vfs_{get,set,remove}xattr helpers libfs: Use IOP_XATTR flag for empty directory handling vfs: Use IOP_XATTR flag for bad-inode handling vfs: Add IOP_XATTR inode operations flag vfs: Move xattr_resolve_name to the front of fs/xattr.c ecryptfs: Switch to generic xattr handlers sockfs: Get rid of getxattr iop sockfs: getxattr: Fail with -EOPNOTSUPP for invalid attribute names kernfs: Switch to generic xattr handlers hfs: Switch to generic xattr handlers jffs2: Remove jffs2_{get,set,remove}xattr macros xattr: Remove unnecessary NULL attribute name check
2016-10-07xattr: Add __vfs_{get,set,remove}xattr helpersAndreas Gruenbacher
Right now, various places in the kernel check for the existence of getxattr, setxattr, and removexattr inode operations and directly call those operations. Switch to helper functions and test for the IOP_XATTR flag instead. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Acked-by: James Morris <james.l.morris@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-10-04Merge branch 'next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security subsystem updates from James Morris: SELinux/LSM: - overlayfs support, necessary for container filesystems LSM: - finally remove the kernel_module_from_file hook Smack: - treat signal delivery as an 'append' operation TPM: - lots of bugfixes & updates Audit: - new audit data type: LSM_AUDIT_DATA_FILE * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (47 commits) Revert "tpm/tpm_crb: implement tpm crb idle state" Revert "tmp/tpm_crb: fix Intel PTT hw bug during idle state" Revert "tpm/tpm_crb: open code the crb_init into acpi_add" Revert "tmp/tpm_crb: implement runtime pm for tpm_crb" lsm,audit,selinux: Introduce a new audit data type LSM_AUDIT_DATA_FILE tmp/tpm_crb: implement runtime pm for tpm_crb tpm/tpm_crb: open code the crb_init into acpi_add tmp/tpm_crb: fix Intel PTT hw bug during idle state tpm/tpm_crb: implement tpm crb idle state tpm: add check for minimum buffer size in tpm_transmit() tpm: constify TPM 1.x header structures tpm/tpm_crb: fix the over 80 characters checkpatch warring tpm/tpm_crb: drop useless cpu_to_le32 when writing to registers tpm/tpm_crb: cache cmd_size register value. tmp/tpm_crb: drop include to platform_device tpm/tpm_tis: remove unused itpm variable tpm_crb: fix incorrect values of cmdReady and goIdle bits tpm_crb: refine the naming of constants tpm_crb: remove wmb()'s tpm_crb: fix crb_req_canceled behavior ...
2016-09-19ovl: during copy up, switch to mounter's creds earlyVivek Goyal
Now, we have the notion that copy up of a file is done with the creds of mounter of overlay filesystem (as opposed to task). Right now before we switch creds, we do some vfs_getattr() operations in the context of task and that itself can fail. We should do that getattr() using the creds of mounter instead. So this patch switches to mounter's creds early during copy up process so that even vfs_getattr() is done with mounter's creds. Do not call revert_creds() unless we have already called ovl_override_creds(). [Reported by Arnd Bergmann] Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-09-16ovl: copy_up_xattr(): use strnlenMiklos Szeredi
Be defensive about what underlying fs provides us in the returned xattr list buffer. strlen() may overrun the buffer, so use strnlen() and WARN if the contents are not properly null terminated. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org>
2016-08-08security,overlayfs: Provide security hook for copy up of xattrs for overlay fileVivek Goyal
Provide a security hook which is called when xattrs of a file are being copied up. This hook is called once for each xattr and LSM can return 0 if the security module wants the xattr to be copied up, 1 if the security module wants the xattr to be discarded on the copy, -EOPNOTSUPP if the security module does not handle/manage the xattr, or a -errno upon an error. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> [PM: whitespace cleanup for checkpatch.pl] Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-08security, overlayfs: provide copy up security hook for unioned filesVivek Goyal
Provide a security hook to label new file correctly when a file is copied up from lower layer to upper layer of a overlay/union mount. This hook can prepare a new set of creds which are suitable for new file creation during copy up. Caller will use new creds to create file and then revert back to old creds and release new creds. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Stephen Smalley <sds@tycho.nsa.gov> [PM: whitespace cleanup to appease checkpatch.pl] Signed-off-by: Paul Moore <paul@paul-moore.com>
2016-08-08ovl: don't copy up opaquenessMiklos Szeredi
When a copy up of a directory occurs which has the opaque xattr set, the xattr remains in the upper directory. The immediate behavior with overlayfs is that the upper directory is not treated as opaque, however after a remount the opaque flag is used and upper directory is treated as opaque. This causes files created in the lower layer to be hidden when using multiple lower directories. Fix by not copying up the opaque flag. To reproduce: ----8<---------8<---------8<---------8<---------8<---------8<---- mkdir -p l/d/s u v w mnt mount -t overlay overlay -olowerdir=l,upperdir=u,workdir=w mnt rm -rf mnt/d/ mkdir -p mnt/d/n umount mnt mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt touch mnt/d/foo umount mnt mount -t overlay overlay -olowerdir=u:l,upperdir=v,workdir=w mnt ls mnt/d ----8<---------8<---------8<---------8<---------8<---------8<---- output should be: "foo n" Reported-by: Derek McGowan <dmcg@drizz.net> Link: https://bugzilla.kernel.org/show_bug.cgi?id=151291 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org>
2016-07-29ovl: store real inode pointer in ->i_privateMiklos Szeredi
To get from overlay inode to real inode we currently use 'struct ovl_entry', which has lifetime connected to overlay dentry. This is okay, since each overlay dentry had a new overlay inode allocated. Following patch will break that assumption, so need to leave out ovl_entry. This patch stores the real inode directly in i_private, with the lowest bit used to indicate whether the inode is upper or lower. Lifetime rules remain, using ovl_inode_real() must only be done while caller holds ref on overlay dentry (and hence on real dentry), or within RCU protected regions. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-05-27ovl: override creds with the ones from the superblock mounterAntonio Murdaca
In user namespace the whiteout creation fails with -EPERM because the current process isn't capable(CAP_SYS_ADMIN) when setting xattr. A simple reproducer: $ mkdir upper lower work merged lower/dir $ sudo mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merged $ unshare -m -p -f -U -r bash Now as root in the user namespace: \# touch merged/dir/{1,2,3} # this will force a copy up of lower/dir \# rm -fR merged/* This ends up failing with -EPERM after the files in dir has been correctly deleted: unlinkat(4, "2", 0) = 0 unlinkat(4, "1", 0) = 0 unlinkat(4, "3", 0) = 0 close(4) = 0 unlinkat(AT_FDCWD, "merged/dir", AT_REMOVEDIR) = -1 EPERM (Operation not permitted) Interestingly, if you don't place files in merged/dir you can remove it, meaning if upper/dir does not exist, creating the char device file works properly in that same location. This patch uses ovl_sb_creator_cred() to get the cred struct from the superblock mounter and override the old cred with these new ones so that the whiteout creation is possible because overlay is wrong in assuming that the creds it will get with prepare_creds will be in the initial user namespace. The old cap_raise game is removed in favor of just overriding the old cred struct. This patch also drops from ovl_copy_up_one() the following two lines: override_cred->fsuid = stat->uid; override_cred->fsgid = stat->gid; This is because the correct uid and gid are taken directly with the stat struct and correctly set with ovl_set_attr(). Signed-off-by: Antonio Murdaca <runcom@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-03-21ovl: fixed coding style warningSohom Bhattacharjee
This patch fixes a newline warning found by the checkpatch.pl tool Signed-off-by: Sohom-Bhattacharjee <soham.bhattacharjee15@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-03-21ovl: Warn on copy up if a process has a R/O fd open to the lower fileDavid Howells
Print a warning when overlayfs copies up a file if the process that triggered the copy up has a R/O fd open to the lower file being copied up. This can help catch applications that do things like the following: fd1 = open("foo", O_RDONLY); fd2 = open("foo", O_RDWR); where they expect fd1 and fd2 to refer to the same file - which will no longer be the case post-copy up. With this patch, the following commands: bash 5</mnt/a/foo128 6<>/mnt/a/foo128 assuming /mnt/a/foo128 to be an un-copied up file on an overlay will produce the following warning in the kernel log: overlayfs: Copying up foo129, but open R/O on fd 5 which will cease to be coherent [pid=3818 bash] This is enabled by setting: /sys/module/overlay/parameters/check_copy_up to 1. The warnings are ratelimited and are also limited to one warning per file - assuming the copy up completes in each case. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2016-01-22wrappers for ->i_mutex accessAl Viro
parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-21Merge branch 'overlayfs-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs updates from Miklos Szeredi: "This contains several bug fixes and a new mount option 'default_permissions' that allows read-only exported NFS filesystems to be used as lower layer" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: check dentry positiveness in ovl_cleanup_whiteouts() ovl: setattr: check permissions before copy-up ovl: root: copy attr ovl: move super block magic number to magic.h ovl: use a minimal buffer in ovl_copy_xattr ovl: allow zero size xattr ovl: default permissions
2015-12-06ovl: get rid of the dead code left from broken (and disabled) optimizationsAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-11-10ovl: use a minimal buffer in ovl_copy_xattrVito Caputo
Rather than always allocating the high-order XATTR_SIZE_MAX buffer which is costly and prone to failure, only allocate what is needed and realloc if necessary. Fixes https://github.com/coreos/bugs/issues/489 Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org>
2015-11-10ovl: allow zero size xattrMiklos Szeredi
When ovl_copy_xattr() encountered a zero size xattr no more xattrs were copied and the function returned success. This is clearly not the desired behavior. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org>
2015-10-12ovl: fix dentry reference leakDavid Howells
In ovl_copy_up_locked(), newdentry is leaked if the function exits through out_cleanup as this just to out after calling ovl_cleanup() - which doesn't actually release the ref on newdentry. The out_cleanup segment should instead exit through out2 as certainly newdentry leaks - and possibly upper does also, though this isn't caught given the catch of newdentry. Without this fix, something like the following is seen: BUG: Dentry ffff880023e9eb20{i=f861,n=#ffff880023e82d90} still in use (1) [unmount of tmpfs tmpfs] BUG: Dentry ffff880023ece640{i=0,n=bigfile} still in use (1) [unmount of tmpfs tmpfs] when unmounting the upper layer after an error occurred in copyup. An error can be induced by creating a big file in a lower layer with something like: dd if=/dev/zero of=/lower/a/bigfile bs=65536 count=1 seek=$((0xf000)) to create a large file (4.1G). Overlay an upper layer that is too small (on tmpfs might do) and then induce a copy up by opening it writably. Reported-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org> # v3.18+
2015-10-12ovl: use O_LARGEFILE in ovl_copy_up()David Howells
Open the lower file with O_LARGEFILE in ovl_copy_up(). Pass O_LARGEFILE unconditionally in ovl_copy_up_data() as it's purely for catching 32-bit userspace dealing with a file large enough that it'll be mishandled if the application isn't aware that there might be an integer overflow. Inside the kernel, there shouldn't be any problems. Reported-by: Ulrich Obergfell <uobergfe@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: <stable@vger.kernel.org> # v3.18+
2015-05-19ovl: mount read-only if workdir can't be createdMiklos Szeredi
OpenWRT folks reported that overlayfs fails to mount if upper fs is full, because workdir can't be created. Wordir creation can fail for various other reasons too. There's no reason that the mount itself should fail, overlayfs can work fine without a workdir, as long as the overlay isn't modified. So mount it read-only and don't allow remounting read-write. Add a couple of WARN_ON()s for the impossible case of workdir being used despite being read-only. Reported-by: Bastian Bittorf <bittorf@bluebottle.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: <stable@vger.kernel.org> # v3.18+
2014-12-13ovl: Cleanup redundant blank lineshujianyang
This patch removes redundant blanks lines in overlayfs. Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-12-13ovl: make path-type a bitmapMiklos Szeredi
OVL_PATH_PURE_UPPER -> __OVL_PATH_UPPER | __OVL_PATH_PURE OVL_PATH_UPPER -> __OVL_PATH_UPPER OVL_PATH_MERGE -> __OVL_PATH_UPPER | __OVL_PATH_MERGE OVL_PATH_LOWER -> 0 Multiple R/O layers will allow __OVL_PATH_MERGE without __OVL_PATH_UPPER. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2014-10-24overlay filesystemMiklos Szeredi
Overlayfs allows one, usually read-write, directory tree to be overlaid onto another, read-only directory tree. All modifications go to the upper, writable layer. This type of mechanism is most often used for live CDs but there's a wide variety of other uses. The implementation differs from other "union filesystem" implementations in that after a file is opened all operations go directly to the underlying, lower or upper, filesystems. This simplifies the implementation and allows native performance in these cases. The dentry tree is duplicated from the underlying filesystems, this enables fast cached lookups without adding special support into the VFS. This uses slightly more memory than union mounts, but dentries are relatively small. Currently inodes are duplicated as well, but it is a possible optimization to share inodes for non-directories. Opening non directories results in the open forwarded to the underlying filesystem. This makes the behavior very similar to union mounts (with the same limitations vs. fchmod/fchown on O_RDONLY file descriptors). Usage: mount -t overlayfs overlayfs -olowerdir=/lower,upperdir=/upper/upper,workdir=/upper/work /overlay The following cotributions have been folded into this patch: Neil Brown <neilb@suse.de>: - minimal remount support - use correct seek function for directories - initialise is_real before use - rename ovl_fill_cache to ovl_dir_read Felix Fietkau <nbd@openwrt.org>: - fix a deadlock in ovl_dir_read_merged - fix a deadlock in ovl_remove_whiteouts Erez Zadok <ezk@fsl.cs.sunysb.edu> - fix cleanup after WARN_ON Sedat Dilek <sedat.dilek@googlemail.com> - fix up permission to confirm to new API Robin Dong <hao.bigrat@gmail.com> - fix possible leak in ovl_new_inode - create new inode in ovl_link Andy Whitcroft <apw@canonical.com> - switch to __inode_permission() - copy up i_uid/i_gid from the underlying inode AV: - ovl_copy_up_locked() - dput(ERR_PTR(...)) on two failure exits - ovl_clear_empty() - one failure exit forgetting to do unlock_rename(), lack of check for udir being the parent of upper, dropping and regaining the lock on udir (which would require _another_ check for parent being right). - bogus d_drop() in copyup and rename [fix from your mail] - copyup/remove and copyup/rename races [fix from your mail] - ovl_dir_fsync() leaving ERR_PTR() in ->realfile - ovl_entry_free() is pointless - it's just a kfree_rcu() - fold ovl_do_lookup() into ovl_lookup() - manually assigning ->d_op is wrong. Just use ->s_d_op. [patches picked from Miklos]: * copyup/remove and copyup/rename races * bogus d_drop() in copyup and rename Also thanks to the following people for testing and reporting bugs: Jordi Pujol <jordipujolp@gmail.com> Andy Whitcroft <apw@canonical.com> Michal Suchanek <hramrach@centrum.cz> Felix Fietkau <nbd@openwrt.org> Erez Zadok <ezk@fsl.cs.sunysb.edu> Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>