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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>
2019-05-08Merge 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>
2019-05-02overlayfs: 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>
2018-11-02Merge tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linuxLinus Torvalds2-22/+27
Pull vfs dedup fixes from Dave Chinner: "This reworks the vfs data cloning infrastructure. We discovered many issues with these interfaces late in the 4.19 cycle - the worst of them (data corruption, setuid stripping) were fixed for XFS in 4.19-rc8, but a larger rework of the infrastructure fixing all the problems was needed. That rework is the contents of this pull request. Rework the vfs_clone_file_range and vfs_dedupe_file_range infrastructure to use a common .remap_file_range method and supply generic bounds and sanity checking functions that are shared with the data write path. The current VFS infrastructure has problems with rlimit, LFS file sizes, file time stamps, maximum filesystem file sizes, stripping setuid bits, etc and so they are addressed in these commits. We also introduce the ability for the ->remap_file_range methods to return short clones so that clones for vfs_copy_file_range() don't get rejected if the entire range can't be cloned. It also allows filesystems to sliently skip deduplication of partial EOF blocks if they are not capable of doing so without requiring errors to be thrown to userspace. Existing filesystems are converted to user the new remap_file_range method, and both XFS and ocfs2 are modified to make use of the new generic checking infrastructure" * tag 'xfs-4.20-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: (28 commits) xfs: remove [cm]time update from reflink calls xfs: remove xfs_reflink_remap_range xfs: remove redundant remap partial EOF block checks xfs: support returning partial reflink results xfs: clean up xfs_reflink_remap_blocks call site xfs: fix pagecache truncation prior to reflink ocfs2: remove ocfs2_reflink_remap_range ocfs2: support partial clone range and dedupe range ocfs2: fix pagecache truncation prior to reflink ocfs2: truncate page cache for clone destination file before remapping vfs: clean up generic_remap_file_range_prep return value vfs: hide file range comparison function vfs: enable remap callers that can handle short operations vfs: plumb remap flags through the vfs dedupe functions vfs: plumb remap flags through the vfs clone functions vfs: make remap_file_range functions take and return bytes completed vfs: remap helper should update destination inode metadata vfs: pass remap flags to generic_remap_checks vfs: pass remap flags to generic_remap_file_range_prep vfs: combine the clone and dedupe into a single remap_file_range ...
2018-11-01ovl: automatically enable redirect_dir on metacopy=onMiklos Szeredi1-7/+29
Current behavior is to automatically disable metacopy if redirect_dir is not enabled and proceed with the mount. If "metacopy=on" mount option was given, then this behavior can confuse the user: no mount failure, yet metacopy is disabled. This patch makes metacopy=on imply redirect_dir=on. The converse is also true: turning off full redirect with redirect_dir= {off|follow|nofollow} will disable metacopy. If both metacopy=on and redirect_dir={off|follow|nofollow} is specified, then mount will fail, since there's no way to correctly resolve the conflict. Reported-by: Daniel Walsh <dwalsh@redhat.com> Fixes: d5791044d2e5 ("ovl: Provide a mount option metacopy=on/off...") Cc: <stable@vger.kernel.org> # v4.19 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-31ovl: check whiteout in ovl_create_over_whiteout()Miklos Szeredi1-0/+4
Kaixuxia repors that it's possible to crash overlayfs by removing the whiteout on the upper layer before creating a directory over it. This is a reproducer: mkdir lower upper work merge touch lower/file mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merge rm merge/file ls -al merge/file rm upper/file ls -al merge/ mkdir merge/file Before commencing with a vfs_rename(..., RENAME_EXCHANGE) verify that the lookup of "upper" is positive and is a whiteout, and return ESTALE otherwise. Reported by: kaixuxia <xiakaixu1987@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: e9be9d5e76e3 ("overlay filesystem") Cc: <stable@vger.kernel.org> # v3.18
2018-10-30vfs: plumb remap flags through the vfs dedupe functionsDarrick J. Wong1-1/+2
Plumb a remap_flags argument through the vfs_dedupe_file_range_one functions so that dedupe can take advantage of it. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: plumb remap flags through the vfs clone functionsDarrick J. Wong2-4/+4
Plumb a remap_flags argument through the {do,vfs}_clone_file_range functions so that clone can take advantage of it. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: make remap_file_range functions take and return bytes completedDarrick J. Wong2-9/+9
Change the remap_file_range functions to take a number of bytes to operate upon and return the number of bytes they operated on. This is a requirement for allowing fs implementations to return short clone/dedupe results to the user, which will enable us to obey resource limits in a graceful manner. A subsequent patch will enable copy_file_range to signal to the ->clone_file_range implementation that it can handle a short length, which will be returned in the function's return value. For now the short return is not implemented anywhere so the behavior won't change -- either copy_file_range manages to clone the entire range or it tries an alternative. Neither clone ioctl can take advantage of this, alas. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-30vfs: combine the clone and dedupe into a single remap_file_rangeDarrick J. Wong1-13/+17
Combine the clone_file_range and dedupe_file_range operations into a single remap_file_range file operation dispatch since they're fundamentally the same operation. The differences between the two can be made in the prep functions. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <david@fromorbit.com>
2018-10-27ovl: using posix_acl_xattr_size() to get size instead of posix_acl_to_xattr()Chengguang Xu1-3/+2
There is no functional change but it seems better to get size by calling posix_acl_xattr_size() instead of calling posix_acl_to_xattr() with NULL buffer argument. Additionally, remove unnecessary assignments. Signed-off-by: Chengguang Xu <cgxu519@gmx.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: abstract ovl_inode lock with a helperAmir Goldstein2-12/+23
The abstraction improves code readabilty (to some). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: remove the 'locked' argument of ovl_nlink_{start,end}Amir Goldstein3-28/+25
It just makes the interface strange without adding any significant value. The only case where locked is false and return value is 0 is in ovl_rename() when new is negative, so handle that case explicitly in ovl_rename(). Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: relax requirement for non null uuid of lower fsAmir Goldstein2-4/+31
We use uuid to associate an overlay lower file handle with a lower layer, so we can accept lower fs with null uuid as long as all lower layers with null uuid are on the same fs. This change allows enabling index and nfs_export features for the setup of single lower fs of type squashfs - squashfs supports file handles, but has a null uuid. This change also allows enabling index and nfs_export features for nested overlayfs, where the lower overlay has nfs_export enabled. Enabling the index feature with single lower squashfs fixes the unionmount-testsuite test: ./run --ov --squashfs --verify As a by-product, if, like the lower squashfs, upper fs also uses the generic export_encode_fh() implementation to export 32bit inode file handles (e.g. ext4), then the xino_auto config/module/mount option will enable unique overlay inode numbers. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: fold copy-up helpers into callersMiklos Szeredi1-108/+67
Now that the workdir and tmpfile copy up modes have been untagled, the functions become simple enough that the helpers can be folded into the callers. Add new helpers where there is any duplication remaining: preparing creds for creating the object. Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: untangle copy up call chainAmir Goldstein1-86/+159
In an attempt to dedup ~100 LOC, we ended up creating a tangled call chain, whose branches merge and diverge in several points according to the immutable c->tmpfile copy up mode. This call chain was hard to analyse for locking correctness because the locking requirements for the c->tmpfile flow were very different from the locking requirements for the !c->tmpfile flow (i.e. directory vs. regulare file copy up). Split the copy up helpers of the c->tmpfile flow from those of the !c->tmpfile (i.e. workdir) flow and remove the c->tmpfile mode from copy up context. 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>
2018-10-27ovl: relax permission checking on underlying layersMiklos Szeredi1-4/+13
Make permission checking more consistent: - special files don't need any access check on underling fs - exec permission check doesn't need to be performed on underlying fs Reported-by: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: fix recursive oi->lock in ovl_link()Amir Goldstein1-0/+4
linking a non-copied-up file into a non-copied-up parent results in a nested call to mutex_lock_interruptible(&oi->lock). Fix this by copying up target parent before ovl_nlink_start(), same as done in ovl_rename(). ~/unionmount-testsuite$ ./run --ov -s ~/unionmount-testsuite$ ln /mnt/a/foo100 /mnt/a/dir100/ WARNING: possible recursive locking detected -------------------------------------------- ln/1545 is trying to acquire lock: 00000000bcce7c4c (&ovl_i_lock_key[depth]){+.+.}, at: ovl_copy_up_start+0x28/0x7d but task is already holding lock: 0000000026d73d5b (&ovl_i_lock_key[depth]){+.+.}, at: ovl_nlink_start+0x3c/0xc1 [SzM: this seems to be a false positive, but doing the copy-up first is harmless and removes the lockdep splat] Reported-by: syzbot+3ef5c0d1a5cb0b21e6be@syzkaller.appspotmail.com Fixes: 5f8415d6b87e ("ovl: persistent overlay inode nlink for...") Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: clean up error handling in ovl_get_tmpfile()Miklos Szeredi1-3/+2
If security_inode_copy_up() fails, it should not set new_creds, so no need for the cleanup (which would've Oops-ed anyway, due to old_creds being NULL). Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-27ovl: fix error handling in ovl_verify_set_fh()Amir Goldstein1-1/+3
We hit a BUG on kfree of an ERR_PTR()... Reported-by: syzbot+ff03fe05c717b82502d0@syzkaller.appspotmail.com Fixes: 8b88a2e64036 ("ovl: verify upper root dir matches lower root dir") Cc: <stable@vger.kernel.org> # v4.13 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-04ovl: fix format of setxattr debugMiklos Szeredi1-2/+2
Format has a typo: it was meant to be "%.*s", not "%*s". But at some point callers grew nonprintable values as well, so use "%*pE" instead with a maximized length. Reported-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up") Cc: <stable@vger.kernel.org> # v4.12
2018-10-04ovl: fix access beyond unterminated stringsAmir Goldstein1-1/+1
KASAN detected slab-out-of-bounds access in printk from overlayfs, because string format used %*s instead of %.*s. > BUG: KASAN: slab-out-of-bounds in string+0x298/0x2d0 lib/vsprintf.c:604 > Read of size 1 at addr ffff8801c36c66ba by task syz-executor2/27811 > > CPU: 0 PID: 27811 Comm: syz-executor2 Not tainted 4.19.0-rc5+ #36 ... > printk+0xa7/0xcf kernel/printk/printk.c:1996 > ovl_lookup_index.cold.15+0xe8/0x1f8 fs/overlayfs/namei.c:689 Reported-by: syzbot+376cea2b0ef340db3dd4@syzkaller.appspotmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Fixes: 359f392ca53e ("ovl: lookup index entry for copy up origin") Cc: <stable@vger.kernel.org> # v4.13
2018-09-25ovl: make symbol 'ovl_aops' staticWei Yongjun1-1/+1
Fixes the following sparse warning: fs/overlayfs/inode.c:507:39: warning: symbol 'ovl_aops' was not declared. Should it be static? Fixes: 5b910bd615ba ("ovl: fix GPF in swapfile_activate of file from overlayfs over xfs") Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-24vfs: swap names of {do,vfs}_clone_file_range()Amir Goldstein2-2/+2
Commit 031a072a0b8a ("vfs: call vfs_clone_file_range() under freeze protection") created a wrapper do_clone_file_range() around vfs_clone_file_range() moving the freeze protection to former, so overlayfs could call the latter. The more common vfs practice is to call do_xxx helpers from vfs_xxx helpers, where freeze protecction is taken in the vfs_xxx helper, so this anomality could be a source of confusion. It seems that commit 8ede205541ff ("ovl: add reflink/copyfile/dedup support") may have fallen a victim to this confusion - ovl_clone_file_range() calls the vfs_clone_file_range() helper in the hope of getting freeze protection on upper fs, but in fact results in overlayfs allowing to bypass upper fs freeze protection. Swap the names of the two helpers to conform to common vfs practice and call the correct helpers from overlayfs and nfsd. Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-24ovl: fix freeze protection bypass in ovl_clone_file_range()Amir Goldstein1-1/+1
Tested by doing clone on overlayfs while upper xfs+reflink is frozen: xfs_io -f /ovl/y fsfreeze -f /xfs xfs_io> reflink /ovl/x Before the fix xfs_io enters xfs_reflink_remap_range() and blocks in xfs_trans_alloc(). After the fix, xfs_io blocks outside xfs code in ovl_clone_file_range(). Fixes: 8ede205541ff ("ovl: add reflink/copyfile/dedup support") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-09-24ovl: fix freeze protection bypass in ovl_write_iter()Amir Goldstein1-0/+2
Tested by re-writing to an open overlayfs file while upper ext4 is frozen: xfs_io -f /ovl/x xfs_io> pwrite 0 4096 fsfreeze -f /ext4 xfs_io> pwrite 0 4096 WARNING: CPU: 0 PID: 1492 at fs/ext4/ext4_jbd2.c:53 \ ext4_journal_check_start+0x48/0x82 After the fix, the second write blocks in ovl_write_iter() and avoids hitting WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE) in ext4_journal_check_start(). Fixes: 2a92e07edc5e ("ovl: add ovl_write_iter()") Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>