kernel.git/fs/overlayfs/dir.c, branch linux-5.4.y

ovl: Use ovl mounter's fsuid and fsgid in ovl_link()

2023-01-18T10:41:43Z

commit 5b0db51215e895a361bc63132caa7cca36a53d6a upstream. There is a wrong case of link() on overlay: $ mkdir /lower /fuse /merge $ mount -t fuse /fuse $ mkdir /fuse/upper /fuse/work $ mount -t overlay /merge -o lowerdir=/lower,upperdir=/fuse/upper,\ workdir=work $ touch /merge/file $ chown bin.bin /merge/file // the file's caller becomes "bin" $ ln /merge/file /merge/lnkfile Then we will get an error(EACCES) because fuse daemon checks the link()'s caller is "bin", it denied this request. In the changing history of ovl_link(), there are two key commits: The first is commit bb0d2b8ad296 ("ovl: fix sgid on directory") which overrides the cred's fsuid/fsgid using the new inode. The new inode's owner is initialized by inode_init_owner(), and inode->fsuid is assigned to the current user. So the override fsuid becomes the current user. We know link() is actually modifying the directory, so the caller must have the MAY_WRITE permission on the directory. The current caller may should have this permission. This is acceptable to use the caller's fsuid. The second is commit 51f7e52dc943 ("ovl: share inode for hard link") which removed the inode creation in ovl_link(). This commit move inode_init_owner() into ovl_create_object(), so the ovl_link() just give the old inode to ovl_create_or_link(). Then the override fsuid becomes the old inode's fsuid, neither the caller nor the overlay's mounter! So this is incorrect. Fix this bug by using ovl mounter's fsuid/fsgid to do underlying fs's link(). Link: https://lore.kernel.org/all/20220817102952.xnvesg3a7rbv576x@wittgenstein/T Link: https://lore.kernel.org/lkml/20220825130552.29587-1-zhangtianci.1997@bytedance.com/t Signed-off-by: Zhang Tianci Signed-off-by: Jiachen Zhang Reviewed-by: Christian Brauner (Microsoft) Fixes: 51f7e52dc943 ("ovl: share inode for hard link") Cc: # v4.8 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix warning in ovl_create_real()

2021-12-22T08:29:40Z

commit 1f5573cfe7a7056e80a92c7a037a3e69f3a13d1c upstream. Syzbot triggered the following warning in ovl_workdir_create() -> ovl_create_real(): if (!err && WARN_ON(!newdentry->d_inode)) { The reason is that the cgroup2 filesystem returns from mkdir without instantiating the new dentry. Weird filesystems such as this will be rejected by overlayfs at a later stage during setup, but to prevent such a warning, call ovl_mkdir_real() directly from ovl_workdir_create() and reject this case early. Reported-and-tested-by: syzbot+75eab84fd0af9e8bf66b@syzkaller.appspotmail.com Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix missing negative dentry check in ovl_rename()

2021-10-13T08:08:17Z

commit a295aef603e109a47af355477326bd41151765b6 upstream. The following reproducer mkdir lower upper work merge touch lower/old touch lower/new mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merge rm merge/new mv merge/old merge/new & unlink upper/new may result in this race: PROCESS A: rename("merge/old", "merge/new"); overwrite=true,ovl_lower_positive(old)=true, ovl_dentry_is_whiteout(new)=true -> flags |= RENAME_EXCHANGE PROCESS B: unlink("upper/new"); PROCESS A: lookup newdentry in new_upperdir call vfs_rename() with negative newdentry and RENAME_EXCHANGE Fix by adding the missing check for negative newdentry. Signed-off-by: Zheng Liang Fixes: e9be9d5e76e3 ("overlay filesystem") Cc: # v3.18 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix BUG_ON() in may_delete() when called from ovl_cleanup()

2021-09-22T10:26:37Z

commit 52d5a0c6bd8a89f460243ed937856354f8f253a3 upstream. If function ovl_instantiate() returns an error, ovl_cleanup will be called and try to remove newdentry from wdir, but the newdentry has been moved to udir at this time. This will causes BUG_ON(victim->d_parent->d_inode != dir) in fs/namei.c:may_delete. Signed-off-by: chenying Fixes: 01b39dcc9568 ("ovl: use inode_insert5() to hash a newly created inode") Link: https://lore.kernel.org/linux-unionfs/e6496a94-a161-dc04-c38a-d2544633acb4@bytedance.com/ Cc: # v4.18 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: fix dentry leak in ovl_get_redirect

2021-02-10T08:25:29Z

commit e04527fefba6e4e66492f122cf8cc6314f3cf3bf upstream. We need to lock d_parent->d_lock before dget_dlock, or this may have d_lockref updated parallelly like calltrace below which will cause dentry->d_lockref leak and risk a crash. CPU 0 CPU 1 ovl_set_redirect lookup_fast ovl_get_redirect __d_lookup dget_dlock //no lock protection here spin_lock(&dentry->d_lock) dentry->d_lockref.count++ dentry->d_lockref.count++ [ 49.799059] PGD 800000061fed7067 P4D 800000061fed7067 PUD 61fec5067 PMD 0 [ 49.799689] Oops: 0002 [#1] SMP PTI [ 49.800019] CPU: 2 PID: 2332 Comm: node Not tainted 4.19.24-7.20.al7.x86_64 #1 [ 49.800678] Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 8a46cfe 04/01/2014 [ 49.801380] RIP: 0010:_raw_spin_lock+0xc/0x20 [ 49.803470] RSP: 0018:ffffac6fc5417e98 EFLAGS: 00010246 [ 49.803949] RAX: 0000000000000000 RBX: ffff93b8da3446c0 RCX: 0000000a00000000 [ 49.804600] RDX: 0000000000000001 RSI: 000000000000000a RDI: 0000000000000088 [ 49.805252] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff993cf040 [ 49.805898] R10: ffff93b92292e580 R11: ffffd27f188a4b80 R12: 0000000000000000 [ 49.806548] R13: 00000000ffffff9c R14: 00000000fffffffe R15: ffff93b8da3446c0 [ 49.807200] FS: 00007ffbedffb700(0000) GS:ffff93b927880000(0000) knlGS:0000000000000000 [ 49.807935] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.808461] CR2: 0000000000000088 CR3: 00000005e3f74006 CR4: 00000000003606a0 [ 49.809113] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 49.809758] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 49.810410] Call Trace: [ 49.810653] d_delete+0x2c/0xb0 [ 49.810951] vfs_rmdir+0xfd/0x120 [ 49.811264] do_rmdir+0x14f/0x1a0 [ 49.811573] do_syscall_64+0x5b/0x190 [ 49.811917] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 49.812385] RIP: 0033:0x7ffbf505ffd7 [ 49.814404] RSP: 002b:00007ffbedffada8 EFLAGS: 00000297 ORIG_RAX: 0000000000000054 [ 49.815098] RAX: ffffffffffffffda RBX: 00007ffbedffb640 RCX: 00007ffbf505ffd7 [ 49.815744] RDX: 0000000004449700 RSI: 0000000000000000 RDI: 0000000006c8cd50 [ 49.816394] RBP: 00007ffbedffaea0 R08: 0000000000000000 R09: 0000000000017d0b [ 49.817038] R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000012 [ 49.817687] R13: 00000000072823d8 R14: 00007ffbedffb700 R15: 00000000072823d8 [ 49.818338] Modules linked in: pvpanic cirrusfb button qemu_fw_cfg atkbd libps2 i8042 [ 49.819052] CR2: 0000000000000088 [ 49.819368] ---[ end trace 4e652b8aa299aa2d ]--- [ 49.819796] RIP: 0010:_raw_spin_lock+0xc/0x20 [ 49.821880] RSP: 0018:ffffac6fc5417e98 EFLAGS: 00010246 [ 49.822363] RAX: 0000000000000000 RBX: ffff93b8da3446c0 RCX: 0000000a00000000 [ 49.823008] RDX: 0000000000000001 RSI: 000000000000000a RDI: 0000000000000088 [ 49.823658] RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff993cf040 [ 49.825404] R10: ffff93b92292e580 R11: ffffd27f188a4b80 R12: 0000000000000000 [ 49.827147] R13: 00000000ffffff9c R14: 00000000fffffffe R15: ffff93b8da3446c0 [ 49.828890] FS: 00007ffbedffb700(0000) GS:ffff93b927880000(0000) knlGS:0000000000000000 [ 49.830725] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 49.832359] CR2: 0000000000000088 CR3: 00000005e3f74006 CR4: 00000000003606a0 [ 49.834085] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 49.835792] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Cc: Fixes: a6c606551141 ("ovl: redirect on rename-dir") Signed-off-by: Liangyan Reviewed-by: Joseph Qi Suggested-by: Al Viro Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

ovl: relax WARN_ON() on rename to self

2019-12-17T18:56:11Z

commit 6889ee5a53b8d969aa542047f5ac8acdc0e79a91 upstream. 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: # v4.9+ Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

Merge tag 'spdx-5.2-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx

2019-06-21T16:58:42Z

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 ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55Z

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 Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

ovl: fix typo in MODULE_PARM_DESC

2019-06-18T13:06:16Z

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 Signed-off-by: Miklos Szeredi

ovl: relax WARN_ON() for overlapping layers use case

2019-05-08T11:25:53Z

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 Signed-off-by: Miklos Szeredi