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* Revert "fs: fold open_check_o_direct into do_dentry_open"Al Viro2018-06-031-18/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit cab64df194667dc5d9d786f0a895f647f5501c0d. Having vfs_open() in some cases drop the reference to struct file combined with error = vfs_open(path, f, cred); if (error) { put_filp(f); return ERR_PTR(error); } return f; is flat-out wrong. It used to be error = vfs_open(path, f, cred); if (!error) { /* from now on we need fput() to dispose of f */ error = open_check_o_direct(f); if (error) { fput(f); f = ERR_PTR(error); } } else { put_filp(f); f = ERR_PTR(error); } and sure, having that open_check_o_direct() boilerplate gotten rid of is nice, but not that way... Worse, another call chain (via finish_open()) is FUBAR now wrt FILE_OPENED handling - in that case we get error returned, with file already hit by fput() *AND* FILE_OPENED not set. Guess what happens in path_openat(), when it hits if (!(opened & FILE_OPENED)) { BUG_ON(!error); put_filp(file); } The root cause of all that crap is that the callers of do_dentry_open() have no way to tell which way did it fail; while that could be fixed up (by passing something like int *opened to do_dentry_open() and have it marked if we'd called ->open()), it's probably much too late in the cycle to do so right now. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'work.misc' of ↵Linus Torvalds2018-04-061-26/+18
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted stuff, including Christoph's I_DIRTY patches" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs: move I_DIRTY_INODE to fs.h ubifs: fix bogus __mark_inode_dirty(I_DIRTY_SYNC | I_DIRTY_DATASYNC) call ntfs: fix bogus __mark_inode_dirty(I_DIRTY_SYNC | I_DIRTY_DATASYNC) call gfs2: fix bogus __mark_inode_dirty(I_DIRTY_SYNC | I_DIRTY_DATASYNC) calls fs: fold open_check_o_direct into do_dentry_open vfs: Replace stray non-ASCII homoglyph characters with their ASCII equivalents vfs: make sure struct filename->iname is word-aligned get rid of pointless includes of fs_struct.h [poll] annotate SAA6588_CMD_POLL users
| * fs: fold open_check_o_direct into do_dentry_openChristoph Hellwig2018-03-281-26/+18
| | | | | | | | | | | | | | | | | | do_dentry_open is where we do the actual open of the file, so this is where we should do our O_DIRECT sanity check to cover all potential callers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | fs: add ksys_fallocate() wrapper; remove in-kernel calls to sys_fallocate()Dominik Brodowski2018-04-021-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using the ksys_fallocate() wrapper allows us to get rid of in-kernel calls to the sys_fallocate() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_fallocate(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add ksys_truncate() wrapper; remove in-kernel calls to sys_truncate()Dominik Brodowski2018-04-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using the ksys_truncate() wrapper allows us to get rid of in-kernel calls to the sys_truncate() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_truncate(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add ksys_open() wrapper; remove in-kernel calls to sys_open()Dominik Brodowski2018-04-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using this wrapper allows us to avoid the in-kernel calls to the sys_open() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_open(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add ksys_close() wrapper; remove in-kernel calls to sys_close()Dominik Brodowski2018-04-021-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using the ksys_close() wrapper allows us to get rid of in-kernel calls to the sys_close() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_close(), with one subtle difference: The few places which checked the return value did not care about the return value re-writing in sys_close(), so simply use a wrapper around __close_fd(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add ksys_ftruncate() wrapper; remove in-kernel calls to sys_ftruncate()Dominik Brodowski2018-04-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using the ksys_ftruncate() wrapper allows us to get rid of in-kernel calls to the sys_ftruncate() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_ftruncate(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add do_fchownat(), ksys_fchown() helpers and ksys_{,l}chown() wrappersDominik Brodowski2018-04-021-6/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using the fs-interal do_fchownat() wrapper allows us to get rid of fs-internal calls to the sys_fchownat() syscall. Introducing the ksys_fchown() helper and the ksys_{,}chown() wrappers allows us to avoid the in-kernel calls to the sys_{,l,f}chown() syscalls. The ksys_ prefix denotes that these functions are meant as a drop-in replacement for the syscalls. In particular, they use the same calling convention as sys_{,l,f}chown(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add do_faccessat() helper and ksys_access() wrapper; remove in-kernel ↵Dominik Brodowski2018-04-021-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | calls to syscall Using the fs-internal do_faccessat() helper allows us to get rid of fs-internal calls to the sys_faccessat() syscall. Introducing the ksys_access() wrapper allows us to avoid the in-kernel calls to the sys_access() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_access(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add ksys_fchmod() and do_fchmodat() helpers and ksys_chmod() wrapper; ↵Dominik Brodowski2018-04-021-3/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | remove in-kernel calls to syscall Using the fs-internal do_fchmodat() helper allows us to get rid of fs-internal calls to the sys_fchmodat() syscall. Introducing the ksys_fchmod() helper and the ksys_chmod() wrapper allows us to avoid the in-kernel calls to the sys_fchmod() and sys_chmod() syscalls. The ksys_ prefix denotes that these functions are meant as a drop-in replacement for the syscalls. In particular, they use the same calling convention as sys_fchmod() and sys_chmod(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add ksys_chdir() helper; remove in-kernel calls to sys_chdir()Dominik Brodowski2018-04-021-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using this helper allows us to avoid the in-kernel calls to the sys_chdir() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_chdir(). This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* | fs: add ksys_chroot() helper; remove-in kernel calls to sys_chroot()Dominik Brodowski2018-04-021-1/+6
|/ | | | | | | | | | | | | | | | | | Using this helper allows us to avoid the in-kernel calls to the sys_chroot() syscall. The ksys_ prefix denotes that this function is meant as a drop-in replacement for the syscall. In particular, it uses the same calling convention as sys_chroot(). In the near future, the fs-external callers of ksys_chroot() should be converted to use kern_path()/set_fs_root() directly. Then ksys_chroot() can be moved within sys_chroot() again. This patch is part of a series which removes in-kernel calls to syscalls. On this basis, the syscall entry path can be streamlined. For details, see http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
* ovl: don't allow writing ioctl on lower layerMiklos Szeredi2017-09-051-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Problem with ioctl() is that it's a file operation, yet often used as an inode operation (i.e. modify the inode despite the file being opened for read-only). mnt_want_write_file() is used by filesystems in such cases to get write access on an arbitrary open file. Since overlayfs lets filesystems do all file operations, including ioctl, this can lead to mnt_want_write_file() returning OK for a lower file and modification of that lower file. This patch prevents modification by checking if the file is from an overlayfs lower layer and returning EPERM in that case. Need to introduce a mnt_want_write_file_path() variant that still does the old thing for inode operations that can do the copy up + modification correctly in such cases (fchown, fsetxattr, fremovexattr). This does not address the correctness of such ioctls on overlayfs (the correct way would be to copy up and attempt to perform ioctl on upper file). In theory this could be a regression. We very much hope that nobody is relying on such a hack in any sane setup. While this patch meddles in VFS code, it has no effect on non-overlayfs filesystems. Reported-by: "zhangyi (F)" <yi.zhang@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* vfs: add flags to d_real()Miklos Szeredi2017-09-041-2/+2
| | | | | | | Add a separate flags argument (in addition to the open flags) to control the behavior of d_real(). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Merge tag 'for-linus-v4.13-2' of ↵Linus Torvalds2017-07-071-0/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux Pull Writeback error handling updates from Jeff Layton: "This pile represents the bulk of the writeback error handling fixes that I have for this cycle. Some of the earlier patches in this pile may look trivial but they are prerequisites for later patches in the series. The aim of this set is to improve how we track and report writeback errors to userland. Most applications that care about data integrity will periodically call fsync/fdatasync/msync to ensure that their writes have made it to the backing store. For a very long time, we have tracked writeback errors using two flags in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a writeback error occurs (via mapping_set_error) and are cleared as a side-effect of filemap_check_errors (as you noted yesterday). This model really sucks for userland. Only the first task to call fsync (or msync or fdatasync) will see the error. Any subsequent task calling fsync on a file will get back 0 (unless another writeback error occurs in the interim). If I have several tasks writing to a file and calling fsync to ensure that their writes got stored, then I need to have them coordinate with one another. That's difficult enough, but in a world of containerized setups that coordination may even not be possible. But wait...it gets worse! The calls to filemap_check_errors can be buried pretty far down in the call stack, and there are internal callers of filemap_write_and_wait and the like that also end up clearing those errors. Many of those callers ignore the error return from that function or return it to userland at nonsensical times (e.g. truncate() or stat()). If I get back -EIO on a truncate, there is no reason to think that it was because some previous writeback failed, and a subsequent fsync() will (incorrectly) return 0. This pile aims to do three things: 1) ensure that when a writeback error occurs that that error will be reported to userland on a subsequent fsync/fdatasync/msync call, regardless of what internal callers are doing 2) report writeback errors on all file descriptions that were open at the time that the error occurred. This is a user-visible change, but I think most applications are written to assume this behavior anyway. Those that aren't are unlikely to be hurt by it. 3) document what filesystems should do when there is a writeback error. Today, there is very little consistency between them, and a lot of cargo-cult copying. We need to make it very clear what filesystems should do in this situation. To achieve this, the set adds a new data type (errseq_t) and then builds new writeback error tracking infrastructure around that. Once all of that is in place, we change the filesystems to use the new infrastructure for reporting wb errors to userland. Note that this is just the initial foray into cleaning up this mess. There is a lot of work remaining here: 1) convert the rest of the filesystems in a similar fashion. Once the initial set is in, then I think most other fs' will be fairly simple to convert. Hopefully most of those can in via individual filesystem trees. 2) convert internal waiters on writeback to use errseq_t for detecting errors instead of relying on the AS_* flags. I have some draft patches for this for ext4, but they are not quite ready for prime time yet. This was a discussion topic this year at LSF/MM too. If you're interested in the gory details, LWN has some good articles about this: https://lwn.net/Articles/718734/ https://lwn.net/Articles/724307/" * tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux: btrfs: minimal conversion to errseq_t writeback error reporting on fsync xfs: minimal conversion to errseq_t writeback error reporting ext4: use errseq_t based error handling for reporting data writeback errors fs: convert __generic_file_fsync to use errseq_t based reporting block: convert to errseq_t based writeback error tracking dax: set errors in mapping when writeback fails Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error fs: new infrastructure for writeback error handling and reporting lib: add errseq_t type and infrastructure for handling it mm: don't TestClearPageError in __filemap_fdatawait_range mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails jbd2: don't clear and reset errors after waiting on writeback buffer: set errors in mapping at the time that the error occurs fs: check for writeback errors after syncing out buffers in generic_file_fsync buffer: use mapping_set_error instead of setting the flag mm: fix mapping_set_error call in me_pagecache_dirty
| * fs: new infrastructure for writeback error handling and reportingJeff Layton2017-07-061-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most filesystems currently use mapping_set_error and filemap_check_errors for setting and reporting/clearing writeback errors at the mapping level. filemap_check_errors is indirectly called from most of the filemap_fdatawait_* functions and from filemap_write_and_wait*. These functions are called from all sorts of contexts to wait on writeback to finish -- e.g. mostly in fsync, but also in truncate calls, getattr, etc. The non-fsync callers are problematic. We should be reporting writeback errors during fsync, but many places spread over the tree clear out errors before they can be properly reported, or report errors at nonsensical times. If I get -EIO on a stat() call, there is no reason for me to assume that it is because some previous writeback failed. The fact that it also clears out the error such that a subsequent fsync returns 0 is a bug, and a nasty one since that's potentially silent data corruption. This patch adds a small bit of new infrastructure for setting and reporting errors during address_space writeback. While the above was my original impetus for adding this, I think it's also the case that current fsync semantics are just problematic for userland. Most applications that call fsync do so to ensure that the data they wrote has hit the backing store. In the case where there are multiple writers to the file at the same time, this is really hard to determine. The first one to call fsync will see any stored error, and the rest get back 0. The processes with open fds may not be associated with one another in any way. They could even be in different containers, so ensuring coordination between all fsync callers is not really an option. One way to remedy this would be to track what file descriptor was used to dirty the file, but that's rather cumbersome and would likely be slow. However, there is a simpler way to improve the semantics here without incurring too much overhead. This set adds an errseq_t to struct address_space, and a corresponding one is added to struct file. Writeback errors are recorded in the mapping's errseq_t, and the one in struct file is used as the "since" value. This changes the semantics of the Linux fsync implementation such that applications can now use it to determine whether there were any writeback errors since fsync(fd) was last called (or since the file was opened in the case of fsync having never been called). Note that those writeback errors may have occurred when writing data that was dirtied via an entirely different fd, but that's the case now with the current mapping_set_error/filemap_check_error infrastructure. This will at least prevent you from getting a false report of success. The new behavior is still consistent with the POSIX spec, and is more reliable for application developers. This patch just adds some basic infrastructure for doing this, and ensures that the f_wb_err "cursor" is properly set when a file is opened. Later patches will change the existing code to use this new infrastructure for reporting errors at fsync time. Signed-off-by: Jeff Layton <jlayton@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz>
* | fs: add fcntl() interface for setting/getting write life time hintsJens Axboe2017-06-271-0/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Define a set of write life time hints: RWH_WRITE_LIFE_NOT_SET No hint information set RWH_WRITE_LIFE_NONE No hints about write life time RWH_WRITE_LIFE_SHORT Data written has a short life time RWH_WRITE_LIFE_MEDIUM Data written has a medium life time RWH_WRITE_LIFE_LONG Data written has a long life time RWH_WRITE_LIFE_EXTREME Data written has an extremely long life time The intent is for these values to be relative to each other, no absolute meaning should be attached to these flag names. Add an fcntl interface for querying these flags, and also for setting them as well: F_GET_RW_HINT Returns the read/write hint set on the underlying inode. F_SET_RW_HINT Set one of the above write hints on the underlying inode. F_GET_FILE_RW_HINT Returns the read/write hint set on the file descriptor. F_SET_FILE_RW_HINT Set one of the above write hints on the file descriptor. The user passes in a 64-bit pointer to get/set these values, and the interface returns 0/-1 on success/error. Sample program testing/implementing basic setting/getting of write hints is below. Add support for storing the write life time hint in the inode flags and in struct file as well, and pass them to the kiocb flags. If both a file and its corresponding inode has a write hint, then we use the one in the file, if available. The file hint can be used for sync/direct IO, for buffered writeback only the inode hint is available. This is in preparation for utilizing these hints in the block layer, to guide on-media data placement. /* * writehint.c: get or set an inode write hint */ #include <stdio.h> #include <fcntl.h> #include <stdlib.h> #include <unistd.h> #include <stdbool.h> #include <inttypes.h> #ifndef F_GET_RW_HINT #define F_LINUX_SPECIFIC_BASE 1024 #define F_GET_RW_HINT (F_LINUX_SPECIFIC_BASE + 11) #define F_SET_RW_HINT (F_LINUX_SPECIFIC_BASE + 12) #endif static char *str[] = { "RWF_WRITE_LIFE_NOT_SET", "RWH_WRITE_LIFE_NONE", "RWH_WRITE_LIFE_SHORT", "RWH_WRITE_LIFE_MEDIUM", "RWH_WRITE_LIFE_LONG", "RWH_WRITE_LIFE_EXTREME" }; int main(int argc, char *argv[]) { uint64_t hint; int fd, ret; if (argc < 2) { fprintf(stderr, "%s: file <hint>\n", argv[0]); return 1; } fd = open(argv[1], O_RDONLY); if (fd < 0) { perror("open"); return 2; } if (argc > 2) { hint = atoi(argv[2]); ret = fcntl(fd, F_SET_RW_HINT, &hint); if (ret < 0) { perror("fcntl: F_SET_RW_HINT"); return 4; } } ret = fcntl(fd, F_GET_RW_HINT, &hint); if (ret < 0) { perror("fcntl: F_GET_RW_HINT"); return 3; } printf("%s: hint %s\n", argv[1], str[hint]); close(fd); return 0; } Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge branch 'work.sane_pwd' of ↵Linus Torvalds2017-05-121-6/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Making sure that something like a referral point won't end up as pwd or root. The main part is the last commit (fixing mntns_install()); that one fixes a hard-to-hit race. The fchdir() commit is making fchdir(2) a bit more robust - it should be impossible to get opened files (even O_PATH ones) for referral points in the first place, so the existing checks are OK, but checking the same thing as in chdir(2) is just as cheap. The path_init() commit removes a redundant check that shouldn't have been there in the first place" * 'work.sane_pwd' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: make sure that mntns_install() doesn't end up with referral for root path_init(): don't bother with checking MAY_EXEC for LOOKUP_ROOT make sure that fchdir() won't accept referral points, etc.
| * make sure that fchdir() won't accept referral points, etc.Al Viro2017-04-211-6/+3
| | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'overlayfs-linus' of ↵Linus Torvalds2017-05-101-1/+2
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs update from Miklos Szeredi: "The biggest part of this is making st_dev/st_ino on the overlay behave like a normal filesystem (i.e. st_ino doesn't change on copy up, st_dev is the same for all files and directories). Currently this only works if all layers are on the same filesystem, but future work will move the general case towards more sane behavior. There are also miscellaneous fixes, including fixes to handling append-only files. There's a small change in the VFS, but that only has an effect on overlayfs, since otherwise file->f_path.dentry->inode and file_inode(file) are always the same" * 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: update documentation w.r.t. constant inode numbers ovl: persistent inode numbers for upper hardlinks ovl: merge getattr for dir and nondir ovl: constant st_ino/st_dev across copy up ovl: persistent inode number for directories ovl: set the ORIGIN type flag ovl: lookup non-dir copy-up-origin by file handle ovl: use an auxiliary var for overlay root entry ovl: store file handle of lower inode on copy up ovl: check if all layers are on the same fs ovl: do not set overlay.opaque on non-dir create ovl: check IS_APPEND() on real upper inode vfs: ftruncate check IS_APPEND() on real upper inode ovl: Use designated initializers ovl: lockdep annotate of nested stacked overlayfs inode lock
| * | vfs: ftruncate check IS_APPEND() on real upper inodeAmir Goldstein2017-04-201-1/+2
| |/ | | | | | | | | | | | | | | | | | | ftruncate an overlayfs inode was checking IS_APPEND() on overlay inode, but overlay inode does not have the S_APPEND flag. Check IS_APPEND() on real upper inode instead. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | Merge branch 'work.misc' of ↵Linus Torvalds2017-05-091-0/+6
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc vfs updates from Al Viro: "Assorted bits and pieces from various people. No common topic in this pile, sorry" * 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs/affs: add rename exchange fs/affs: add rename2 to prepare multiple methods Make stat/lstat/fstatat pass AT_NO_AUTOMOUNT to vfs_statx() fs: don't set *REFERENCED on single use objects fs: compat: Remove warning from COMPATIBLE_IOCTL remove pointless extern of atime_need_update_rcu() fs: completely ignore unknown open flags fs: add a VALID_OPEN_FLAGS fs: remove _submit_bh() fs: constify tree_descr arrays passed to simple_fill_super() fs: drop duplicate header percpu-rwsem.h fs/affs: bugfix: Write files greater than page size on OFS fs/affs: bugfix: enable writes on OFS disks fs/affs: remove node generation check fs/affs: import amigaffs.h fs/affs: bugfix: make symbolic links work again
| * | fs: completely ignore unknown open flagsChristoph Hellwig2017-04-271-0/+6
| |/ | | | | | | | | | | | | | | | | Currently we just stash anything we got into file->f_flags, and the report it in fcntl(F_GETFD). This patch just clears out all unknown flags so that we don't pass them to the fs or report them. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* / open: move compat syscalls from compat.cAl Viro2017-04-171-0/+20
|/ | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: wrap write f_ops with file_{start,end}_write()Amir Goldstein2017-02-071-2/+2
| | | | | | | | | | | | | | | | Before calling write f_ops, call file_start_write() instead of sb_start_write(). Replace {sb,file}_start_write() for {copy,clone}_file_range() and for fallocate(). Beyond correct semantics, this avoids freeze protection to sb when operating on special inodes, such as fallocate() on a blockdev. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* vfs: deny fallocate() on directoryAmir Goldstein2017-02-071-6/+4
| | | | | | | | | | | | | | | | | | | | | | There was an obscure use case of fallocate of directory inode in the vfs helper with the comment: "Let individual file system decide if it supports preallocation for directories or not." But there is no in-tree file system that implements fallocate for directory operations. Deny an attempt to fallocate a directory with EISDIR error. This change is needed prior to converting sb_start_write() to file_start_write(), so freeze protection is correctly handled for cases of fallocate file and blockdev. Cc: linux-api@vger.kernel.org Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* Replace <asm/uaccess.h> with <linux/uaccess.h> globallyLinus Torvalds2016-12-241-1/+1
| | | | | | | | | | | | | This was entirely automated, using the script by Al: PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>' sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \ $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h) to do the replacement at the end of the merge window. Requested-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'xfs-reflink-for-linus-4.9-rc1' of ↵Linus Torvalds2016-10-131-0/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs < XFS has gained super CoW powers! > ---------------------------------- \ ^__^ \ (oo)\_______ (__)\ )\/\ ||----w | || || Pull XFS support for shared data extents from Dave Chinner: "This is the second part of the XFS updates for this merge cycle. This pullreq contains the new shared data extents feature for XFS. Given the complexity and size of this change I am expecting - like the addition of reverse mapping last cycle - that there will be some follow-up bug fixes and cleanups around the -rc3 stage for issues that I'm sure will show up once the code hits a wider userbase. What it is: At the most basic level we are simply adding shared data extents to XFS - i.e. a single extent on disk can now have multiple owners. To do this we have to add new on-disk features to both track the shared extents and the number of times they've been shared. This is done by the new "refcount" btree that sits in every allocation group. When we share or unshare an extent, this tree gets updated. Along with this new tree, the reverse mapping tree needs to be updated to track each owner or a shared extent. This also needs to be updated ever share/unshare operation. These interactions at extent allocation and freeing time have complex ordering and recovery constraints, so there's a significant amount of new intent-based transaction code to ensure that operations are performed atomically from both the runtime and integrity/crash recovery perspectives. We also need to break sharing when writes hit a shared extent - this is where the new copy-on-write implementation comes in. We allocate new storage and copy the original data along with the overwrite data into the new location. We only do this for data as we don't share metadata at all - each inode has it's own metadata that tracks the shared data extents, the extents undergoing CoW and it's own private extents. Of course, being XFS, nothing is simple - we use delayed allocation for CoW similar to how we use it for normal writes. ENOSPC is a significant issue here - we build on the reservation code added in 4.8-rc1 with the reverse mapping feature to ensure we don't get spurious ENOSPC issues part way through a CoW operation. These mechanisms also help minimise fragmentation due to repeated CoW operations. To further reduce fragmentation overhead, we've also introduced a CoW extent size hint, which indicates how large a region we should allocate when we execute a CoW operation. With all this functionality in place, we can hook up .copy_file_range, .clone_file_range and .dedupe_file_range and we gain all the capabilities of reflink and other vfs provided functionality that enable manipulation to shared extents. We also added a fallocate mode that explicitly unshares a range of a file, which we implemented as an explicit CoW of all the shared extents in a file. As such, it's a huge chunk of new functionality with new on-disk format features and internal infrastructure. It warns at mount time as an experimental feature and that it may eat data (as we do with all new on-disk features until they stabilise). We have not released userspace suport for it yet - userspace support currently requires download from Darrick's xfsprogs repo and build from source, so the access to this feature is really developer/tester only at this point. Initial userspace support will be released at the same time the kernel with this code in it is released. The new code causes 5-6 new failures with xfstests - these aren't serious functional failures but things the output of tests changing slightly due to perturbations in layouts, space usage, etc. OTOH, we've added 150+ new tests to xfstests that specifically exercise this new functionality so it's got far better test coverage than any functionality we've previously added to XFS. Darrick has done a pretty amazing job getting us to this stage, and special mention also needs to go to Christoph (review, testing, improvements and bug fixes) and Brian (caught several intricate bugs during review) for the effort they've also put in. Summary: - unshare range (FALLOC_FL_UNSHARE) support for fallocate - copy-on-write extent size hints (FS_XFLAG_COWEXTSIZE) for fsxattr interface - shared extent support for XFS - copy-on-write support for shared extents - copy_file_range support - clone_file_range support (implements reflink) - dedupe_file_range support - defrag support for reverse mapping enabled filesystems" * tag 'xfs-reflink-for-linus-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (71 commits) xfs: convert COW blocks to real blocks before unwritten extent conversion xfs: rework refcount cow recovery error handling xfs: clear reflink flag if setting realtime flag xfs: fix error initialization xfs: fix label inaccuracies xfs: remove isize check from unshare operation xfs: reduce stack usage of _reflink_clear_inode_flag xfs: check inode reflink flag before calling reflink functions xfs: implement swapext for rmap filesystems xfs: refactor swapext code xfs: various swapext cleanups xfs: recognize the reflink feature bit xfs: simulate per-AG reservations being critically low xfs: don't mix reflink and DAX mode for now xfs: check for invalid inode reflink flags xfs: set a default CoW extent size of 32 blocks xfs: convert unwritten status of reverse mappings for shared files xfs: use interval query for rmap alloc operations on shared files xfs: add shared rmap map/unmap/convert log item types xfs: increase log reservations for reflink ...
| * vfs: add a FALLOC_FL_UNSHARE mode to fallocate to unshare a range of blocksDarrick J. Wong2016-10-031-0/+5
| | | | | | | | | | | | | | | | Add a new fallocate mode flag that explicitly unshares blocks on filesystems that support such features. The new flag can only be used with an allocate-mode fallocate call. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
* | block: implement (some of) fallocate for block devicesDarrick J. Wong2016-10-111-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After much discussion, it seems that the fallocate feature flag FALLOC_FL_ZERO_RANGE maps nicely to SCSI WRITE SAME; and the feature FALLOC_FL_PUNCH_HOLE maps nicely to the devices that have been whitelisted for zeroing SCSI UNMAP. Punch still requires that FALLOC_FL_KEEP_SIZE is set. A length that goes past the end of the device will be clamped to the device size if KEEP_SIZE is set; or will return -EINVAL if not. Both start and length must be aligned to the device's logical block size. Since the semantics of fallocate are fairly well established already, wire up the two pieces. The other fallocate variants (collapse range, insert range, and allocate blocks) are not supported. Link: http://lkml.kernel.org/r/147518379992.22791.8849838163218235007.stgit@birch.djwong.org Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Mike Snitzer <snitzer@redhat.com> # tweaked header Cc: Brian Foster <bfoster@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hannes Reinecke <hare@suse.de> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | vfs: do get_write_access() on upper layer of overlayfsMiklos Szeredi2016-09-161-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The problem with writecount is: we want consistent handling of it for underlying filesystems as well as overlayfs. Making sure i_writecount is correct on all layers is difficult. Instead this patch makes sure that when write access is acquired, it's always done on the underlying writable layer (called the upper layer). We must also make sure to look at the writecount on this layer when checking for conflicting leases. Open for write already updates the upper layer's writecount. Leaving only truncate. For truncate copy up must happen before get_write_access() so that the writecount is updated on the upper layer. Problem with this is if something fails after that, then copy-up was done needlessly. E.g. if break_lease() was interrupted. Probably not a big deal in practice. Another interesting case is if there's a denywrite on a lower file that is then opened for write or truncated. With this patch these will succeed, which is somewhat counterintuitive. But I think it's still acceptable, considering that the copy-up does actually create a different file, so the old, denywrite mapping won't be touched. On non-overlayfs d_real() is an identity function and d_real_inode() is equivalent to d_inode() so this patch doesn't change behavior in that case. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Acked-by: Jeff Layton <jlayton@poochiereds.net> Cc: "J. Bruce Fields" <bfields@fieldses.org>
* | locks: fix file locking on overlayfsMiklos Szeredi2016-09-161-1/+1
|/ | | | | | | | | | | | | | | | | | | | This patch allows flock, posix locks, ofd locks and leases to work correctly on overlayfs. Instead of using the underlying inode for storing lock context use the overlay inode. This allows locks to be persistent across copy-up. This is done by introducing locks_inode() helper and using it instead of file_inode() to get the inode in locking code. For non-overlayfs the two are equivalent, except for an extra pointer dereference in locks_inode(). Since lock operations are in "struct file_operations" we must also make sure not to call underlying filesystem's lock operations. Introcude a super block flag MS_NOREMOTELOCK to this effect. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Acked-by: Jeff Layton <jlayton@poochiereds.net> Cc: "J. Bruce Fields" <bfields@fieldses.org>
* Merge tag 'binfmt-for-linus' of ↵Linus Torvalds2016-08-071-0/+20
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jejb/binfmt_misc Pull binfmt_misc update from James Bottomley: "This update is to allow architecture emulation containers to function such that the emulation binary can be housed outside the container itself. The container and fs parts both have acks from relevant experts. To use the new feature you have to add an F option to your binfmt_misc configuration" From the docs: "The usual behaviour of binfmt_misc is to spawn the binary lazily when the misc format file is invoked. However, this doesn't work very well in the face of mount namespaces and changeroots, so the F mode opens the binary as soon as the emulation is installed and uses the opened image to spawn the emulator, meaning it is always available once installed, regardless of how the environment changes" * tag 'binfmt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/binfmt_misc: binfmt_misc: add F option description to documentation binfmt_misc: add persistent opened binary handler for containers fs: add filp_clone_open API
| * fs: add filp_clone_open APIJames Bottomley2016-03-301-0/+20
| | | | | | | | | | | | | | | | | | | | | | I need an API that allows me to obtain a clone of the current file pointer to pass in to an exec handler. I've labelled this as an internal API because I can't see how it would be useful outside of the fs subsystem. The use case will be a persistent binfmt_misc handler. Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Acked-by: Jan Kara <jack@suse.cz>
* | vfs: merge .d_select_inode() into .d_real()Miklos Szeredi2016-06-301-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The two methods essentially do the same: find the real dentry/inode belonging to an overlay dentry. The difference is in the usage: vfs_open() uses ->d_select_inode() and expects the function to perform copy-up if necessary based on the open flags argument. file_dentry() uses ->d_real() passing in the overlay dentry as well as the underlying inode. vfs_rename() uses ->d_select_inode() but passes zero flags. ->d_real() with a zero inode would have worked just as well here. This patch merges the functionality of ->d_select_inode() into ->d_real() by adding an 'open_flags' argument to the latter. [Al Viro] Make the signature of d_real() match that of ->d_real() again. And constify the inode argument, while we are at it. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
* | Merge branch 'work.const-path' of ↵Linus Torvalds2016-05-171-3/+3
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull 'struct path' constification update from Al Viro: "'struct path' is passed by reference to a bunch of Linux security methods; in theory, there's nothing to stop them from modifying the damn thing and LSM community being what it is, sooner or later some enterprising soul is going to decide that it's a good idea. Let's remove the temptation and constify all of those..." * 'work.const-path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: constify ima_d_path() constify security_sb_pivotroot() constify security_path_chroot() constify security_path_{link,rename} apparmor: remove useless checks for NULL ->mnt constify security_path_{mkdir,mknod,symlink} constify security_path_{unlink,rmdir} apparmor: constify common_perm_...() apparmor: constify aa_path_link() apparmor: new helper - common_path_perm() constify chmod_common/security_path_chmod constify security_sb_mount() constify chown_common/security_path_chown tomoyo: constify assorted struct path * apparmor_path_truncate(): path->mnt is never NULL constify vfs_truncate() constify security_path_truncate() [apparmor] constify struct path * in a bunch of helpers
| * | constify chmod_common/security_path_chmodAl Viro2016-03-281-1/+1
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | constify chown_common/security_path_chownAl Viro2016-03-281-1/+1
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * | constify vfs_truncate()Al Viro2016-03-281-1/+1
| |/ | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'ovl-fixes' into for-linusAl Viro2016-05-171-8/+4
|\ \ | | | | | | | | | | | | | | | Backmerge to resolve a conflict in ovl_lookup_real(); "ovl_lookup_real(): use lookup_one_len_unlocked()" instead, but it was too late in the cycle to rebase.
| * | vfs: add vfs_select_inode() helperMiklos Szeredi2016-05-101-8/+4
| |/ | | | | | | | | Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> # v4.2+
* / give readdir(2)/getdents(2)/etc. uniform exclusion with lseek()Al Viro2016-05-021-1/+1
|/ | | | | | same as read() on regular files has, and for the same reason. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* fs/coredump: prevent fsuid=0 dumps into user-controlled directoriesJann Horn2016-03-221-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit fixes the following security hole affecting systems where all of the following conditions are fulfilled: - The fs.suid_dumpable sysctl is set to 2. - The kernel.core_pattern sysctl's value starts with "/". (Systems where kernel.core_pattern starts with "|/" are not affected.) - Unprivileged user namespace creation is permitted. (This is true on Linux >=3.8, but some distributions disallow it by default using a distro patch.) Under these conditions, if a program executes under secure exec rules, causing it to run with the SUID_DUMP_ROOT flag, then unshares its user namespace, changes its root directory and crashes, the coredump will be written using fsuid=0 and a path derived from kernel.core_pattern - but this path is interpreted relative to the root directory of the process, allowing the attacker to control where a coredump will be written with root privileges. To fix the security issue, always interpret core_pattern for dumps that are written under SUID_DUMP_ROOT relative to the root directory of init. Signed-off-by: Jann Horn <jann@thejh.net> Acked-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* wrappers for ->i_mutex accessAl Viro2016-01-221-6/+6
| | | | | | | | | | | 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>
* don't carry MAY_OPEN in op->acc_modeAl Viro2016-01-041-4/+1
| | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: Commit to never having exectuables on proc and sysfs.Eric W. Biederman2015-07-101-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Today proc and sysfs do not contain any executable files. Several applications today mount proc or sysfs without noexec and nosuid and then depend on there being no exectuables files on proc or sysfs. Having any executable files show on proc or sysfs would cause a user space visible regression, and most likely security problems. Therefore commit to never allowing executables on proc and sysfs by adding a new flag to mark them as filesystems without executables and enforce that flag. Test the flag where MNT_NOEXEC is tested today, so that the only user visible effect will be that exectuables will be treated as if the execute bit is cleared. The filesystems proc and sysfs do not currently incoporate any executable files so this does not result in any user visible effects. This makes it unnecessary to vet changes to proc and sysfs tightly for adding exectuable files or changes to chattr that would modify existing files, as no matter what the individual file say they will not be treated as exectuable files by the vfs. Not having to vet changes to closely is important as without this we are only one proc_create call (or another goof up in the implementation of notify_change) from having problematic executables on proc. Those mistakes are all too easy to make and would create a situation where there are security issues or the assumptions of some program having to be broken (and cause userspace regressions). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
* fs: Call security_ops->inode_killpriv on truncateJan Kara2015-06-231-2/+4
| | | | | | | | | | | | | | | | | | | Comment in include/linux/security.h says that ->inode_killpriv() should be called when setuid bit is being removed and that similar security labels (in fact this applies only to file capabilities) should be removed at this time as well. However we don't call ->inode_killpriv() when we remove suid bit on truncate. We fix the problem by calling ->inode_need_killpriv() and subsequently ->inode_killpriv() on truncate the same way as we do it on file write. After this patch there's only one user of should_remove_suid() - ocfs2 - and indeed it's buggy because it doesn't call ->inode_killpriv() on write. However fixing it is difficult because of special locking constraints. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* vfs: add file_path() helperMiklos Szeredi2015-06-231-0/+6
| | | | | | | | | | Turn d_path(&file->f_path, ...); into file_path(file, ...); Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* overlayfs: Make f_path always point to the overlay and f_inode to the underlayDavid Howells2015-06-191-23/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make file->f_path always point to the overlay dentry so that the path in /proc/pid/fd is correct and to ensure that label-based LSMs have access to the overlay as well as the underlay (path-based LSMs probably don't need it). Using my union testsuite to set things up, before the patch I see: [root@andromeda union-testsuite]# bash 5</mnt/a/foo107 [root@andromeda union-testsuite]# ls -l /proc/$$/fd/ ... lr-x------. 1 root root 64 Jun 5 14:38 5 -> /a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 13381 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 13381 Links: 1 ... After the patch: [root@andromeda union-testsuite]# bash 5</mnt/a/foo107 [root@andromeda union-testsuite]# ls -l /proc/$$/fd/ ... lr-x------. 1 root root 64 Jun 5 14:22 5 -> /mnt/a/foo107 [root@andromeda union-testsuite]# stat /mnt/a/foo107 ... Device: 23h/35d Inode: 40346 Links: 1 ... [root@andromeda union-testsuite]# stat -L /proc/$$/fd/5 ... Device: 23h/35d Inode: 40346 Links: 1 ... Note the change in where /proc/$$/fd/5 points to in the ls command. It was pointing to /a/foo107 (which doesn't exist) and now points to /mnt/a/foo107 (which is correct). The inode accessed, however, is the lower layer. The union layer is on device 25h/37d and the upper layer on 24h/36d. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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