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2020-03-13ovl: fix lockdep warning for async writeMiklos Szeredi1-0/+6
Lockdep reports "WARNING: lock held when returning to user space!" due to async write holding freeze lock over the write. Apparently aio.c already deals with this by lying to lockdep about the state of the lock. Do the same here. No need to check for S_IFREG() here since these file ops are regular-only. Reported-by: syzbot+9331a354f4f624a52a55@syzkaller.appspotmail.com Fixes: 2406a307ac7d ("ovl: implement async IO routines") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-13ovl: fix some xino configurationsAmir Goldstein2-1/+9
Fix up two bugs in the coversion to xino_mode: 1. xino=off does not always end up in disabled mode 2. xino=auto on 32bit arch should end up in disabled mode Take a proactive approach to disabling xino on 32bit kernel: 1. Disable XINO_AUTO config during build time 2. Disable xino with a warning on mount time As a by product, xino=on on 32bit arch also ends up in disabled mode. We never intended to enable xino on 32bit arch and this will make the rest of the logic simpler. Fixes: 0f831ec85eda ("ovl: simplify ovl_same_sb() helper") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-03-12ovl: fix lock in ovl_llseek()Amir Goldstein2-3/+8
ovl_inode_lock() is interruptible. When inode_lock() in ovl_llseek() was replaced with ovl_inode_lock(), we did not add a check for error. Fix this by making ovl_inode_lock() uninterruptible and change the existing call sites to use an _interruptible variant. Reported-by: syzbot+66a9752fa927f745385e@syzkaller.appspotmail.com Fixes: b1f9d3858f72 ("ovl: use ovl_inode_lock in ovl_llseek()") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-02-03ovl: fix lseek overflow on 32bitMiklos Szeredi1-1/+1
ovl_lseek() is using ssize_t to return the value from vfs_llseek(). On a 32-bit kernel ssize_t is a 32-bit signed int, which overflows above 2 GB. Assign the return value of vfs_llseek() to loff_t to fix this. Reported-by: Boris Gjenero <boris.gjenero@gmail.com> Fixes: 9e46b840c705 ("ovl: support stacked SEEK_HOLE/SEEK_DATA") Cc: <stable@vger.kernel.org> # v4.19 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24ovl: add splice file read write helperMurphy Zhou1-0/+47
Now overlayfs falls back to use default file splice read and write, which is not compatiple with overlayfs, returning EFAULT. xfstests generic/591 can reproduce part of this. Tested this patch with xfstests auto group tests. Signed-off-by: Murphy Zhou <jencce.kernel@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24ovl: implement async IO routinesJiufei Xue3-15/+110
A performance regression was observed since linux v4.19 with aio test using fio with iodepth 128 on overlayfs. The queue depth of the device was always 1 which is unexpected. After investigation, it was found that commit 16914e6fc7e1 ("ovl: add ovl_read_iter()") and commit 2a92e07edc5e ("ovl: add ovl_write_iter()") resulted in vfs_iter_{read,write} being called on underlying filesystem, which always results in syncronous IO. Implement async IO for stacked reading and writing. This resolves the performance regresion. This is implemented by allocating a new kiocb for submitting the AIO request on the underlying filesystem. When the request is completed, the new kiocb is freed and the completion callback is called on the original iocb. Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24ovl: layer is constMiklos Szeredi6-22/+23
The ovl_layer struct is never modified except at initialization. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24ovl: fix corner case of non-constant st_dev;st_inoAmir Goldstein2-17/+14
On non-samefs overlay without xino, non pure upper inodes should use a pseudo_dev assigned to each unique lower fs, but if lower layer is on the same fs and upper layer, it has no pseudo_dev assigned. In this overlay layers setup: - two filesystems, A and B - upper layer is on A - lower layer 1 is also on A - lower layer 2 is on B Non pure upper overlay inode, whose origin is in layer 1 will have the st_dev;st_ino values of the real lower inode before copy up and the st_dev;st_ino values of the real upper inode after copy up. Fix this inconsitency by assigning a unique pseudo_dev also for upper fs, that will be used as st_dev value along with the lower inode st_dev for overlay inodes in the case above. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24ovl: fix corner case of conflicting lower layer uuidAmir Goldstein2-2/+8
This fixes ovl_lower_uuid_ok() to correctly detect the corner case: - two filesystems, A and B, both have null uuid - upper layer is on A - lower layer 1 is also on A - lower layer 2 is on B In this case, bad_uuid would not have been set for B, because the check only involved the list of lower fs. Hence we'll try to decode a layer 2 origin on layer 1 and fail. We check for conflicting (and null) uuid among all lower layers, including those layers that are on the same fs as the upper layer. Reported-by: Miklos Szeredi <mszeredi@redhat.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24ovl: generalize the lower_fs[] arrayAmir Goldstein3-46/+46
Rename lower_fs[] array to fs[], extend its size by one and use index fsid (instead of fsid-1) to access the fs[] array. Initialize fs[0] with upper fs values. fsid 0 is reserved even with lower only overlay, so fs[0] remains null in this case. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-24ovl: simplify ovl_same_sb() helperAmir Goldstein6-34/+37
No code uses the sb returned from this helper, so make it retrun a boolean and rename it to ovl_same_fs(). The xino mode is irrelevant when all layers are on same fs, so instead of describing samefs with mode OVL_XINO_OFF, use a new xino_mode state, which is 0 in the case of samefs, -1 in the case of xino=off and > 0 with xino enabled. Create a new helper ovl_same_dev(), to use instead of the common check for (ovl_same_fs() || xinobits). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22ovl: generalize the lower_layers[] arrayAmir Goldstein4-31/+35
Rename lower_layers[] array to layers[], extend its size by one and initialize layers[0] with upper layer values. Lower layers are now addressed with index 1..numlower. layers[0] is reserved even with lower only overlay. [SzM: replace ofs->numlower with ofs->numlayer, the latter's value is incremented by one] Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22ovl: improving copy-up efficiency for big sparse fileChengguang Xu1-2/+39
Current copy-up is not efficient for big sparse file, It's not only slow but also wasting more disk space when the target lower file has huge hole inside. This patch tries to recognize file hole and skip it during copy-up. Detail logic of hole detection as below: When we detect next data position is larger than current position we will skip that hole, otherwise we copy data in the size of OVL_COPY_UP_CHUNK_SIZE. Actually, it may not recognize all kind of holes and sometimes only skips partial of hole area. However, it will be enough for most of the use cases. Additionally, this optimization relies on lseek(2) SEEK_DATA implementation, so for some specific filesystems which do not support this feature will behave as before on copy-up. Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Chengguang Xu <cgxu519@mykernel.net> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22ovl: use ovl_inode_lock in ovl_llseek()Amir Goldstein2-2/+23
In ovl_llseek() we use the overlay inode rwsem to protect against concurrent modifications to real file f_pos, because we copy the overlay file f_pos to/from the real file f_pos. This caused a lockdep warning of locking order violation when the ovl_llseek() operation was called on a lower nested overlay layer while the upper layer fs sb_writers is held (with patch improving copy-up efficiency for big sparse file). Use the internal ovl_inode_lock() instead of the overlay inode rwsem in those cases. It is meant to be used for protecting against concurrent changes to overlay inode internal state changes. The locking order rules are documented to explain this case. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22ovl: use pr_fmt auto generate prefixlijiazi9-81/+85
Use pr_fmt auto generate "overlayfs: " prefix. Signed-off-by: lijiazi <lijiazi@xiaomi.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2020-01-22ovl: fix wrong WARN_ON() in ovl_cache_update_ino()Amir Goldstein1-1/+7
The WARN_ON() that child entry is always on overlay st_dev became wrong when we allowed this function to update d_ino in non-samefs setup with xino enabled. It is not true in case of xino bits overflow on a non-dir inode. Leave the WARN_ON() only for directories, where assertion is still true. Fixes: adbf4f7ea834 ("ovl: consistent d_ino for non-samefs with xino") Cc: <stable@vger.kernel.org> # v4.17+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-14Merge tag 'ovl-fixes-5.5-rc2' of ↵Linus Torvalds8-96/+159
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs fixes from Miklos Szeredi: "Fix some bugs and documentation" * tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: docs: filesystems: overlayfs: Fix restview warnings docs: filesystems: overlayfs: Rename overlayfs.txt to .rst ovl: relax WARN_ON() on rename to self ovl: fix corner case of non-unique st_dev;st_ino ovl: don't use a temp buf for encoding real fh ovl: make sure that real fid is 32bit aligned in memory ovl: fix lookup failure on multi lower squashfs
2019-12-10ovl: relax WARN_ON() on rename to selfAmir Goldstein1-1/+1
In ovl_rename(), if new upper is hardlinked to old upper underneath overlayfs before upper dirs are locked, user will get an ESTALE error and a WARN_ON will be printed. Changes to underlying layers while overlayfs is mounted may result in unexpected behavior, but it shouldn't crash the kernel and it shouldn't trigger WARN_ON() either, so relax this WARN_ON(). Reported-by: syzbot+bb1836a212e69f8e201a@syzkaller.appspotmail.com Fixes: 804032fabb3b ("ovl: don't check rename to self") Cc: <stable@vger.kernel.org> # v4.9+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10ovl: fix corner case of non-unique st_dev;st_inoAmir Goldstein1-1/+7
On non-samefs overlay without xino, non pure upper inodes should use a pseudo_dev assigned to each unique lower fs and pure upper inodes use the real upper st_dev. It is fine for an overlay pure upper inode to use the same st_dev;st_ino values as the real upper inode, because the content of those two different filesystem objects is always the same. In this case, however: - two filesystems, A and B - upper layer is on A - lower layer 1 is also on A - lower layer 2 is on B Non pure upper overlay inode, whose origin is in layer 1 will have the same st_dev;st_ino values as the real lower inode. This may result with a false positive results of 'diff' between the real lower and copied up overlay inode. Fix this by using the upper st_dev;st_ino values in this case. This breaks the property of constant st_dev;st_ino across copy up of this case. This breakage will be fixed by a later patch. Fixes: 5148626b806a ("ovl: allocate anon bdev per unique lower fs") Cc: stable@vger.kernel.org # v4.17+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10ovl: don't use a temp buf for encoding real fhAmir Goldstein1-21/+16
We can allocate maximum fh size and encode into it directly. 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>
2019-12-10ovl: make sure that real fid is 32bit aligned in memoryAmir Goldstein4-73/+115
Seprate on-disk encoding from in-memory and on-wire resresentation of overlay file handle. In-memory and on-wire we only ever pass around pointers to struct ovl_fh, which encapsulates at offset 3 the on-disk format struct ovl_fb. struct ovl_fb encapsulates at offset 21 the real file handle. That makes sure that the real file handle is always 32bit aligned in-memory when passed down to the underlying filesystem. On-disk format remains the same and store/load are done into correctly aligned buffer. New nfs exported file handles are exported with aligned real fid. Old nfs file handles are copied to an aligned buffer before being decoded. Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-12-10ovl: fix lookup failure on multi lower squashfsAmir Goldstein3-7/+27
In the past, overlayfs required that lower fs have non null uuid in order to support nfs export and decode copy up origin file handles. Commit 9df085f3c9a2 ("ovl: relax requirement for non null uuid of lower fs") relaxed this requirement for nfs export support, as long as uuid (even if null) is unique among all lower fs. However, said commit unintentionally also relaxed the non null uuid requirement for decoding copy up origin file handles, regardless of the unique uuid requirement. Amend this mistake by disabling decoding of copy up origin file handle from lower fs with a conflicting uuid. We still encode copy up origin file handles from those fs, because file handles like those already exist in the wild and because they might provide useful information in the future. There is an unhandled corner case described by Miklos this way: - two filesystems, A and B, both have null uuid - upper layer is on A - lower layer 1 is also on A - lower layer 2 is on B In this case bad_uuid won't be set for B, because the check only involves the list of lower fs. Hence we'll try to decode a layer 2 origin on layer 1 and fail. We will deal with this corner case later. Reported-by: Colin Ian King <colin.king@canonical.com> Tested-by: Colin Ian King <colin.king@canonical.com> Link: https://lore.kernel.org/lkml/20191106234301.283006-1-colin.king@canonical.com/ Fixes: 9df085f3c9a2 ("ovl: relax requirement for non null uuid ...") Cc: stable@vger.kernel.org # v4.20+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-11-15new helper: lookup_positive_unlocked()Al Viro1-16/+8
Most of the callers of lookup_one_len_unlocked() treat negatives are ERR_PTR(-ENOENT). Provide a helper that would do just that. Note that a pinned positive dentry remains positive - it's ->d_inode is stable, etc.; a pinned _negative_ dentry can become positive at any point as long as you are not holding its parent at least shared. So using lookup_one_len_unlocked() needs to be careful; lookup_positive_unlocked() is safer and that's what the callers end up open-coding anyway. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-09-11ovl: filter of trusted xattr results in auditMark Salyzyn1-1/+2
When filtering xattr list for reading, presence of trusted xattr results in a security audit log. However, if there is other content no errno will be set, and if there isn't, the errno will be -ENODATA and not -EPERM as is usually associated with a lack of capability. The check does not block the request to list the xattrs present. Switch to ns_capable_noaudit to reflect a more appropriate check. Signed-off-by: Mark Salyzyn <salyzyn@android.com> Cc: linux-security-module@vger.kernel.org Cc: kernel-team@android.com Cc: stable@vger.kernel.org # v3.18+ Fixes: a082c6f680da ("ovl: filter trusted xattr for non-admin") Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-09-11ovl: Fix dereferencing possible ERR_PTR()Ding Xiang1-2/+1
if ovl_encode_real_fh() fails, no memory was allocated and the error in the error-valued pointer should be returned. Fixes: 9b6faee07470 ("ovl: check ERR_PTR() return value from ovl_encode_fh()") Signed-off-by: Ding Xiang <dingxiang@cmss.chinamobile.com> Cc: <stable@vger.kernel.org> # v4.16+ Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-07-16ovl: fix regression caused by overlapping layers detectionAmir Goldstein2-26/+48
Once upon a time, commit 2cac0c00a6cd ("ovl: get exclusive ownership on upper/work dirs") in v4.13 added some sanity checks on overlayfs layers. This change caused a docker regression. The root cause was mount leaks by docker, which as far as I know, still exist. To mitigate the regression, commit 85fdee1eef1a ("ovl: fix regression caused by exclusive upper/work dir protection") in v4.14 turned the mount errors into warnings for the default index=off configuration. Recently, commit 146d62e5a586 ("ovl: detect overlapping layers") in v5.2, re-introduced exclusive upper/work dir checks regardless of index=off configuration. This changes the status quo and mount leak related bug reports have started to re-surface. Restore the status quo to fix the regressions. To clarify, index=off does NOT relax overlapping layers check for this ovelayfs mount. index=off only relaxes exclusive upper/work dir checks with another overlayfs mount. To cover the part of overlapping layers detection that used the exclusive upper/work dir checks to detect overlap with self upper/work dir, add a trap also on the work base dir. Link: https://github.com/moby/moby/issues/34672 Link: https://lore.kernel.org/linux-fsdevel/20171006121405.GA32700@veci.piliscsaba.szeredi.hu/ Link: https://github.com/containers/libpod/issues/3540 Fixes: 146d62e5a586 ("ovl: detect overlapping layers") Cc: <stable@vger.kernel.org> # v4.19+ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Tested-by: Colin Walters <walters@verbum.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-21Merge tag 'spdx-5.2-rc6' of ↵Linus Torvalds11-44/+11
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx Pull still more SPDX updates from Greg KH: "Another round of SPDX updates for 5.2-rc6 Here is what I am guessing is going to be the last "big" SPDX update for 5.2. It contains all of the remaining GPLv2 and GPLv2+ updates that were "easy" to determine by pattern matching. The ones after this are going to be a bit more difficult and the people on the spdx list will be discussing them on a case-by-case basis now. Another 5000+ files are fixed up, so our overall totals are: Files checked: 64545 Files with SPDX: 45529 Compared to the 5.1 kernel which was: Files checked: 63848 Files with SPDX: 22576 This is a huge improvement. Also, we deleted another 20000 lines of boilerplate license crud, always nice to see in a diffstat" * tag 'spdx-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: (65 commits) treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 507 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 506 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 504 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 503 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 502 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 501 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 499 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 498 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 497 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 496 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 495 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 491 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 490 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 489 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 488 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 487 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 486 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 485 ...
2019-06-19treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500Thomas Gleixner11-44/+11
Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Enrico Weigelt <info@metux.net> Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19ovl: make i_ino consistent with st_ino in more casesAmir Goldstein1-6/+6
Relax the condition that overlayfs supports nfs export, to require that i_ino is consistent with st_ino/d_ino. It is enough to require that st_ino and d_ino are consistent. This fixes the failure of xfstest generic/504, due to mismatch of st_ino to inode number in the output of /proc/locks. Fixes: 12574a9f4c9c ("ovl: consistent i_ino for non-samefs with xino") Cc: <stable@vger.kernel.org> # v4.19 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-18ovl: fix typo in MODULE_PARM_DESCNicolas Schier3-8/+8
Change first argument to MODULE_PARM_DESC() calls, that each of them matched the actual module parameter name. The matching results in changing (the 'parm' section from) the output of `modinfo overlay` from: parm: ovl_check_copy_up:Obsolete; does nothing parm: redirect_max:ushort parm: ovl_redirect_max:Maximum length of absolute redirect xattr value parm: redirect_dir:bool parm: ovl_redirect_dir_def:Default to on or off for the redirect_dir feature parm: redirect_always_follow:bool parm: ovl_redirect_always_follow:Follow redirects even if redirect_dir feature is turned off parm: index:bool parm: ovl_index_def:Default to on or off for the inodes index feature parm: nfs_export:bool parm: ovl_nfs_export_def:Default to on or off for the NFS export feature parm: xino_auto:bool parm: ovl_xino_auto_def:Auto enable xino feature parm: metacopy:bool parm: ovl_metacopy_def:Default to on or off for the metadata only copy up feature into: parm: check_copy_up:Obsolete; does nothing parm: redirect_max:Maximum length of absolute redirect xattr value (ushort) parm: redirect_dir:Default to on or off for the redirect_dir feature (bool) parm: redirect_always_follow:Follow redirects even if redirect_dir feature is turned off (bool) parm: index:Default to on or off for the inodes index feature (bool) parm: nfs_export:Default to on or off for the NFS export feature (bool) parm: xino_auto:Auto enable xino feature (bool) parm: metacopy:Default to on or off for the metadata only copy up feature (bool) Signed-off-by: Nicolas Schier <n.schier@avm.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-18ovl: fix bogus -Wmaybe-unitialized warningArnd Bergmann1-2/+2
gcc gets a bit confused by the logic in ovl_setup_trap() and can't figure out whether the local 'trap' variable in the caller was initialized or not: fs/overlayfs/super.c: In function 'ovl_fill_super': fs/overlayfs/super.c:1333:4: error: 'trap' may be used uninitialized in this function [-Werror=maybe-uninitialized] iput(trap); ^~~~~~~~~~ fs/overlayfs/super.c:1312:17: note: 'trap' was declared here Reword slightly to make it easier for the compiler to understand. Fixes: 146d62e5a586 ("ovl: detect overlapping layers") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-06-18ovl: don't fail with disconnected lower NFSMiklos Szeredi1-17/+9
NFS mounts can be disconnected from fs root. Don't fail the overlapping layer check because of this. The check is not authoritative anyway, since topology can change during or after the check. Reported-by: Antti Antinoja <antti@fennosys.fi> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 146d62e5a586 ("ovl: detect overlapping layers")
2019-06-11ovl: fix wrong flags check in FS_IOC_FS[SG]ETXATTR ioctlsAmir Goldstein1-26/+65
The ioctl argument was parsed as the wrong type. Fixes: b21d9c435f93 ("ovl: support the FS_IOC_FS[SG]ETXATTR ioctls") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-29ovl: detect overlapping layersAmir Goldstein6-17/+229
Overlapping overlay layers are not supported and can cause unexpected behavior, but overlayfs does not currently check or warn about these configurations. User is not supposed to specify the same directory for upper and lower dirs or for different lower layers and user is not supposed to specify directories that are descendants of each other for overlay layers, but that is exactly what this zysbot repro did: https://syzkaller.appspot.com/x/repro.syz?x=12c7a94f400000 Moving layer root directories into other layers while overlayfs is mounted could also result in unexpected behavior. This commit places "traps" in the overlay inode hash table. Those traps are dummy overlay inodes that are hashed by the layers root inodes. On mount, the hash table trap entries are used to verify that overlay layers are not overlapping. While at it, we also verify that overlay layers are not overlapping with directories "in-use" by other overlay instances as upperdir/workdir. On lookup, the trap entries are used to verify that overlay layers root inodes have not been moved into other layers after mount. Some examples: $ ./run --ov --samefs -s ... ( mkdir -p base/upper/0/u base/upper/0/w base/lower lower upper mnt mount -o bind base/lower lower mount -o bind base/upper upper mount -t overlay none mnt ... -o lowerdir=lower,upperdir=upper/0/u,workdir=upper/0/w) $ umount mnt $ mount -t overlay none mnt ... -o lowerdir=base,upperdir=upper/0/u,workdir=upper/0/w [ 94.434900] overlayfs: overlapping upperdir path mount: mount overlay on mnt failed: Too many levels of symbolic links $ mount -t overlay none mnt ... -o lowerdir=upper/0/u,upperdir=upper/0/u,workdir=upper/0/w [ 151.350132] overlayfs: conflicting lowerdir path mount: none is already mounted or mnt busy $ mount -t overlay none mnt ... -o lowerdir=lower:lower/a,upperdir=upper/0/u,workdir=upper/0/w [ 201.205045] overlayfs: overlapping lowerdir path mount: mount overlay on mnt failed: Too many levels of symbolic links $ mount -t overlay none mnt ... -o lowerdir=lower,upperdir=upper/0/u,workdir=upper/0/w $ mv base/upper/0/ base/lower/ $ find mnt/0 mnt/0 mnt/0/w find: 'mnt/0/w/work': Too many levels of symbolic links find: 'mnt/0/u': Too many levels of symbolic links Reported-by: syzbot+9c69c282adc4edd2b540@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-27ovl: support the FS_IOC_FS[SG]ETXATTR ioctlsAmir Goldstein1-3/+6
They are the extended version of FS_IOC_FS[SG]ETFLAGS ioctls. xfs_io -c "chattr <flags>" uses the new ioctls for setting flags. This used to work in kernel pre v4.19, before stacked file ops introduced the ovl_ioctl whitelist. Reported-by: Dave Chinner <david@fromorbit.com> Fixes: d1d04ef8572b ("ovl: stack file ops") Cc: <stable@vger.kernel.org> # v4.19 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner2-0/+2
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-14Merge tag 'ovl-update-5.2' of ↵Linus Torvalds5-33/+113
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs Pull overlayfs update from Miklos Szeredi: "Just bug fixes in this small update" * tag 'ovl-update-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: relax WARN_ON() for overlapping layers use case ovl: check the capability before cred overridden ovl: do not generate duplicate fsnotify events for "fake" path ovl: support stacked SEEK_HOLE/SEEK_DATA ovl: fix missing upper fs freeze protection on copy up for ioctl
2019-05-08ovl: relax WARN_ON() for overlapping layers use caseAmir Goldstein2-2/+3
This nasty little syzbot repro: https://syzkaller.appspot.com/x/repro.syz?x=12c7a94f400000 Creates overlay mounts where the same directory is both in upper and lower layers. Simplified example: mkdir foo work mount -t overlay none foo -o"lowerdir=.,upperdir=foo,workdir=work" The repro runs several threads in parallel that attempt to chdir into foo and attempt to symlink/rename/exec/mkdir the file bar. The repro hits a WARN_ON() I placed in ovl_instantiate(), which suggests that an overlay inode already exists in cache and is hashed by the pointer of the real upper dentry that ovl_create_real() has just created. At the point of the WARN_ON(), for overlay dir inode lock is held and upper dir inode lock, so at first, I did not see how this was possible. On a closer look, I see that after ovl_create_real(), because of the overlapping upper and lower layers, a lookup by another thread can find the file foo/bar that was just created in upper layer, at overlay path foo/foo/bar and hash the an overlay inode with the new real dentry as lower dentry. This is possible because the overlay directory foo/foo is not locked and the upper dentry foo/bar is in dcache, so ovl_lookup() can find it without taking upper dir inode shared lock. Overlapping layers is considered a wrong setup which would result in unexpected behavior, but it shouldn't crash the kernel and it shouldn't trigger WARN_ON() either, so relax this WARN_ON() and leave a pr_warn() instead to cover all cases of failure to get an overlay inode. The error returned from failure to insert new inode to cache with inode_insert5() was changed to -EEXIST, to distinguish from the error -ENOMEM returned on failure to get/allocate inode with iget5_locked(). Reported-by: syzbot+9c69c282adc4edd2b540@syzkaller.appspotmail.com Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly...") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-07Merge branch 'work.dcache' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc dcache updates from Al Viro: "Most of this pile is putting name length into struct name_snapshot and making use of it. The beginning of this series ("ovl_lookup_real_one(): don't bother with strlen()") ought to have been split in two (separate switch of name_snapshot to struct qstr from overlayfs reaping the trivial benefits of that), but I wanted to avoid a rebase - by the time I'd spotted that it was (a) in -next and (b) close to 5.1-final ;-/" * 'work.dcache' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: audit_compare_dname_path(): switch to const struct qstr * audit_update_watch(): switch to const struct qstr * inotify_handle_event(): don't bother with strlen() fsnotify: switch send_to_group() and ->handle_event to const struct qstr * fsnotify(): switch to passing const struct qstr * for file_name switch fsnotify_move() to passing const struct qstr * for old_name ovl_lookup_real_one(): don't bother with strlen() sysv: bury the broken "quietly truncate the long filenames" logics nsfs: unobfuscate unexport d_alloc_pseudo()
2019-05-06ovl: check the capability before cred overriddenJiufei Xue1-18/+61
We found that it return success when we set IMMUTABLE_FL flag to a file in docker even though the docker didn't have the capability CAP_LINUX_IMMUTABLE. The commit d1d04ef8572b ("ovl: stack file ops") and dab5ca8fd9dd ("ovl: add lsattr/chattr support") implemented chattr operations on a regular overlay file. ovl_real_ioctl() overridden the current process's subjective credentials with ofs->creator_cred which have the capability CAP_LINUX_IMMUTABLE so that it will return success in vfs_ioctl()->cap_capable(). Fix this by checking the capability before cred overridden. And here we only care about APPEND_FL and IMMUTABLE_FL, so get these information from inode. [SzM: move check and call to underlying fs inside inode locked region to prevent two such calls from racing with each other] Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-06ovl: do not generate duplicate fsnotify events for "fake" pathAmir Goldstein1-3/+4
Overlayfs "fake" path is used for stacked file operations on underlying files. Operations on files with "fake" path must not generate fsnotify events with path data, because those events have already been generated at overlayfs layer and because the reported event->fd for fanotify marks on underlying inode/filesystem will have the wrong path (the overlayfs path). Link: https://lore.kernel.org/linux-fsdevel/20190423065024.12695-1-jencce.kernel@gmail.com/ Reported-by: Murphy Zhou <jencce.kernel@gmail.com> Fixes: d1d04ef8572b ("ovl: stack file ops") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-06ovl: support stacked SEEK_HOLE/SEEK_DATAAmir Goldstein1-4/+40
Overlay file f_pos is the master copy that is preserved through copy up and modified on read/write, but only real fs knows how to SEEK_HOLE/SEEK_DATA and real fs may impose limitations that are more strict than ->s_maxbytes for specific files, so we use the real file to perform seeks. We do not call real fs for SEEK_CUR:0 query and for SEEK_SET:0 requests. Fixes: d1d04ef8572b ("ovl: stack file ops") Reported-by: Eddie Horng <eddiehorng.tw@gmail.com> Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-06ovl: fix missing upper fs freeze protection on copy up for ioctlAmir Goldstein3-7/+6
Generalize the helper ovl_open_maybe_copy_up() and use it to copy up file with data before FS_IOC_SETFLAGS ioctl. The FS_IOC_SETFLAGS ioctl is a bit of an odd ball in vfs, which probably caused the confusion. File may be open O_RDONLY, but ioctl modifies the file. VFS does not call mnt_want_write_file() nor lock inode mutex, but fs-specific code for FS_IOC_SETFLAGS does. So ovl_ioctl() calls mnt_want_write_file() for the overlay file, and fs-specific code calls mnt_want_write_file() for upper fs file, but there was no call for ovl_want_write() for copy up duration which prevents overlayfs from copying up on a frozen upper fs. Fixes: dab5ca8fd9dd ("ovl: add lsattr/chattr support") Cc: <stable@vger.kernel.org> # v4.19 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-05-01overlayfs: make use of ->free_inode()Al Viro1-7/+6
synchronous parts are left in ->destroy_inode() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-04-26ovl_lookup_real_one(): don't bother with strlen()Al Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-02-13ovl: Do not lose security.capability xattr over metadata file copy-upVivek Goyal3-22/+63
If a file has been copied up metadata only, and later data is copied up, upper loses any security.capability xattr it has (underlying filesystem clears it as upon file write). From a user's point of view, this is just a file copy-up and that should not result in losing security.capability xattr. Hence, before data copy up, save security.capability xattr (if any) and restore it on upper after data copy up is complete. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Fixes: 0c2888749363 ("ovl: A new xattr OVL_XATTR_METACOPY for file on upper") Cc: <stable@vger.kernel.org> # v4.19+ Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2019-02-04ovl: During copy up, first copy up data and then xattrsVivek Goyal1-13/+18
If a file with capability set (and hence security.capability xattr) is written kernel clears security.capability xattr. For overlay, during file copy up if xattrs are copied up first and then data is, copied up. This means data copy up will result in clearing of security.capability xattr file on lower has. And this can result into surprises. If a lower file has CAP_SETUID, then it should not be cleared over copy up (if nothing was actually written to file). This also creates problems with chown logic where it first copies up file and then tries to clear setuid bit. But by that time security.capability xattr is already gone (due to data copy up), and caller gets -ENODATA. This has been reported by Giuseppe here. https://github.com/containers/libpod/issues/2015#issuecomment-447824842 Fix this by copying up data first and then metadta. This is a regression which has been introduced by my commit as part of metadata only copy up patches. TODO: There will be some corner cases where a file is copied up metadata only and later data copy up happens and that will clear security.capability xattr. Something needs to be done about that too. Fixes: bd64e57586d3 ("ovl: During copy up, first copy up metadata and then data") Cc: <stable@vger.kernel.org> # v4.19+ Reported-by: Giuseppe Scrivano <gscrivan@redhat.com> Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-12-04Revert "ovl: relax permission checking on underlying layers"Miklos Szeredi1-13/+4
This reverts commit 007ea44892e6fa963a0876a979e34890325c64eb. The commit broke some selinux-testsuite cases, and it looks like there's no straightforward fix keeping the direction of this patch, so revert for now. The original patch was trying to fix the consistency of permission checks, and not an observed bug. So reverting should be safe. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-11-21ovl: fix decode of dir file handle with multi lower layersAmir Goldstein1-3/+3
When decoding a lower file handle, we first call ovl_check_origin_fh() with connected=false to get any real lower dentry for overlay inode cache lookup. If the real dentry is a disconnected dir dentry, ovl_check_origin_fh() is called again with connected=true to get a connected real dentry and find the lower layer the real dentry belongs to. If the first call returned a connected real dentry, we use it to lookup an overlay connected dentry, but the first ovl_check_origin_fh() call with connected=false did not check that the found dentry is under the root of the layer (see ovl_acceptable()), it only checked that the found dentry super block matches the uuid of the lower file handle. In case there are multiple lower layers on the same fs and the found dentry is not from the top most lower layer, using the layer index returned from the first ovl_check_origin_fh() is wrong and we end up failing to decode the file handle. Fix this by always calling ovl_check_origin_fh() with connected=true if we got a directory dentry in the first call. Fixes: 8b58924ad55c ("ovl: lookup in inode cache first when decoding...") Cc: <stable@vger.kernel.org> # v4.17 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-11-19ovl: fix missing override creds in link of a metacopy upperAmir Goldstein1-1/+13
Theodore Ts'o reported a v4.19 regression with docker-dropbox: https://marc.info/?l=linux-fsdevel&m=154070089431116&w=2 "I was rebuilding my dropbox Docker container, and it failed in 4.19 with the following error: ... dpkg: error: error creating new backup file \ '/var/lib/dpkg/status-old': Invalid cross-device link" The problem did not reproduce with metacopy feature disabled. The error was caused by insufficient credentials to set "trusted.overlay.redirect" xattr on link of a metacopy file. Reproducer: echo Y > /sys/module/overlay/parameters/redirect_dir echo Y > /sys/module/overlay/parameters/metacopy cd /tmp mkdir l u w m chmod 777 l u touch l/foo ln l/foo l/link chmod 666 l/foo mount -t overlay none -olowerdir=l,upperdir=u,workdir=w m su fsgqa ln m/foo m/bar [ 21.455823] overlayfs: failed to set redirect (-1) ln: failed to create hard link 'm/bar' => 'm/foo':\ Invalid cross-device link Reported-by: Theodore Y. Ts'o <tytso@mit.edu> Reported-by: Maciej Zięba <maciekz82@gmail.com> Fixes: 4120fe64dce4 ("ovl: Set redirect on upper inode when it is linked") Cc: <stable@vger.kernel.org> # v4.19 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
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