- Apr 12, 2021
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Amir Goldstein authored
The test in ovl_dentry_version_inc() was out-dated and did not include the case where readdir cache is used on a non-merge dir that has origin xattr, indicating that it may contain leftover whiteouts. To make the code more robust, use the same helper ovl_dir_is_real() to determine if readdir cache should be used and if readdir cache should be invalidated. Fixes: b79e05aa ("ovl: no direct iteration for dir with origin xattr") Link: https://lore.kernel.org/linux-unionfs/CAOQ4uxht70nODhNHNwGFMSqDyOKLXOKrY0H6g849os4BQ7cokA@mail.gmail.com/ Cc: Chris Murphy <lists@colorremedies.com> Signed-off-by:
Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
Commit 146d62e5 ("ovl: detect overlapping layers") made sure we don't have overlapping layers, but it also broke the arguably valid use case of mount -olowerdir=/,upperdir=/subdir,.. where upperdir overlaps lowerdir on the same filesystem. This has been causing regressions. Revert the check, but only for the specific case where upperdir and/or workdir are subdirectories of lowerdir. Any other overlap (e.g. lowerdir is subdirectory of upperdir, etc) case is crazy, so leave the check in place for those. Overlaps are detected at lookup time too, so reverting the mount time check should be safe. Fixes: 146d62e5 ("ovl: detect overlapping layers") Cc: <stable@vger.kernel.org> # v5.2 Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Giuseppe Scrivano authored
This was missed when adding the option. Signed-off-by:
Giuseppe Scrivano <gscrivan@redhat.com> Reviewed-by:
Vivek Goyal <vgoyal@redhat.com> Fixes: 2d2f2d73 ("ovl: user xattr") Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Bhaskar Chowdhury authored
s/peresistent/persistent/ s/xatts/xattrs/ s/annotaion/annotation/ Signed-off-by:
Bhaskar Chowdhury <unixbhaskar@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Xiong Zhenwu authored
A typo is found out by codespell tool: $ codespell ./fs/overlayfs/ ./fs/overlayfs/util.c:217: dependig ==> depending Fix a typo found by codespell. Signed-off-by:
Xiong Zhenwu <xiong.zhenwu@zte.com.cn> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Chengguang Xu authored
In ovl_xattr_set() we have already copied attr of real inode so no need to copy it again in ovl_posix_acl_xattr_set(). Signed-off-by:
Chengguang Xu <cgxu519@mykernel.net> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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youngjun authored
ovl_map_dev_ino() always returns success. Remove unnecessary return value. Signed-off-by:
youngjun <her0gyugyu@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Chengguang Xu authored
There are some places should return -EINVAL instead of -ENOMEM in ovl_fill_super(). [Amir] Consistently set error before checking the error condition. Signed-off-by:
Chengguang Xu <cgxu519@mykernel.net> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Dan Carpenter authored
Smatch complains about missing that the ovl_override_creds() doesn't have a matching revert_creds() if the dentry is disconnected. Fix this by moving the ovl_override_creds() until after the disconnected check. Fixes: aa3ff3c1 ("ovl: copy up of disconnected dentries") Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Mickaël Salaün authored
Since commit 6815f479 ("ovl: use only uppermetacopy state in ovl_lookup()"), overlayfs doesn't put temporary dentry when there is a metacopy error, which leads to dentry leaks when shutting down the related superblock: overlayfs: refusing to follow metacopy origin for (/file0) ... BUG: Dentry (____ptrval____){i=3f33,n=file3} still in use (1) [unmount of overlay overlay] ... WARNING: CPU: 1 PID: 432 at umount_check.cold+0x107/0x14d CPU: 1 PID: 432 Comm: unmount-overlay Not tainted 5.12.0-rc5 #1 ... RIP: 0010:umount_check.cold+0x107/0x14d ... Call Trace: d_walk+0x28c/0x950 ? dentry_lru_isolate+0x2b0/0x2b0 ? __kasan_slab_free+0x12/0x20 do_one_tree+0x33/0x60 shrink_dcache_for_umount+0x78/0x1d0 generic_shutdown_super+0x70/0x440 kill_anon_super+0x3e/0x70 deactivate_locked_super+0xc4/0x160 deactivate_super+0xfa/0x140 cleanup_mnt+0x22e/0x370 __cleanup_mnt+0x1a/0x30 task_work_run+0x139/0x210 do_exit+0xb0c/0x2820 ? __kasan_check_read+0x1d/0x30 ? find_held_lock+0x35/0x160 ? lock_release+0x1b6/0x660 ? mm_update_next_owner+0xa20/0xa20 ? reacquire_held_locks+0x3f0/0x3f0 ? __sanitizer_cov_trace_const_cmp4+0x22/0x30 do_group_exit+0x135/0x380 __do_sys_exit_group.isra.0+0x20/0x20 __x64_sys_exit_group+0x3c/0x50 do_syscall_64+0x45/0x70 entry_SYSCALL_64_after_hwframe+0x44/0xae ... VFS: Busy inodes after unmount of overlay. Self-destruct in 5 seconds. Have a nice day... This fix has been tested with a syzkaller reproducer. Cc: Amir Goldstein <amir73il@gmail.com> Cc: <stable@vger.kernel.org> # v5.8+ Reported-by:
syzbot <syzkaller@googlegroups.com> Fixes: 6815f479 ("ovl: use only uppermetacopy state in ovl_lookup()") Signed-off-by:
Mickaël Salaün <mic@linux.microsoft.com> Link: https://lore.kernel.org/r/20210329164907.2133175-1-mic@digikod.net Reviewed-by:
Vivek Goyal <vgoyal@redhat.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Amir Goldstein authored
Commit a888db31 ("ovl: fix regression with re-formatted lower squashfs") attempted to fix a regression with existing setups that use a practice that we are trying to discourage. The discourage part was described this way in the commit message: "To avoid the reported regression while still allowing the new features with single lower squashfs, do not allow decoding origin with lower null uuid unless user opted-in to one of the new features that require following the lower inode of non-dir upper (index, xino, metacopy)." The three mentioned features are disabled by default in Kconfig, so it was assumed that if they are enabled, the user opted-in for them. Apparently, distros started to configure CONFIG_OVERLAY_FS_XINO_AUTO=y some time ago, so users upgrading their kernels can still be affected by said regression even though they never opted-in for any new feature. To fix this, treat "xino=on" as "user opted-in", but not "xino=auto". Since we are changing the behavior of "xino=auto" to no longer follow to lower origin with null uuid, take this one step further and disable xino in that corner case. To be consistent, disable xino also in cases of lower fs without file handle support and upper fs without xattr support. Update documentation w.r.t the new "xino=auto" behavior and fix the out dated bits of documentation regarding "xino" and regarding offline modifications to lower layers. Link: https://lore.kernel.org/linux-unionfs/b36a429d7c563730c28d763d4d57a6fc30508a4f.1615216996.git.kevin@kevinlocke.name/ Signed-off-by:
Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Amir Goldstein authored
So far we only checked that sb is not read-only. Suggested-by:
Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by:
Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Sargun Dhillon authored
Filesystems can implement their own flush method that release resources, or manipulate caches. Currently if one of these filesystems is used with overlayfs, the flush method is not called. [Amir: fix fd leak in ovl_flush()] Signed-off-by:
Sargun Dhillon <sargun@sargun.me> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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- Jan 28, 2021
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Sargun Dhillon authored
Overlayfs's volatile option allows the user to bypass all forced sync calls to the upperdir filesystem. This comes at the cost of safety. We can never ensure that the user's data is intact, but we can make a best effort to expose whether or not the data is likely to be in a bad state. The best way to handle this in the time being is that if an overlayfs's upperdir experiences an error after a volatile mount occurs, that error will be returned on fsync, fdatasync, sync, and syncfs. This is contradictory to the traditional behaviour of VFS which fails the call once, and only raises an error if a subsequent fsync error has occurred, and been raised by the filesystem. One awkward aspect of the patch is that we have to manually set the superblock's errseq_t after the sync_fs callback as opposed to just returning an error from syncfs. This is because the call chain looks something like this: sys_syncfs -> sync_filesystem -> __sync_filesystem -> /* The return value is ignored here sb->s_op->sync_fs(sb) _sync_blockdev /* Where the VFS fetches the error to raise to userspace */ errseq_check_and_advance Because of this we call errseq_set every time the sync_fs callback occurs. Due to the nature of this seen / unseen dichotomy, if the upperdir is an inconsistent state at the initial mount time, overlayfs will refuse to mount, as overlayfs cannot get a snapshot of the upperdir's errseq that will increment on error until the user calls syncfs. Signed-off-by:
Sargun Dhillon <sargun@sargun.me> Suggested-by:
Amir Goldstein <amir73il@gmail.com> Reviewed-by:
Amir Goldstein <amir73il@gmail.com> Fixes: c86243b0 ("ovl: provide a mount option "volatile"") Cc: stable@vger.kernel.org Reviewed-by:
Vivek Goyal <vgoyal@redhat.com> Reviewed-by:
Jeff Layton <jlayton@kernel.org> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Amir Goldstein authored
When inode has no listxattr op of its own (e.g. squashfs) vfs_listxattr calls the LSM inode_listsecurity hooks to list the xattrs that LSMs will intercept in inode_getxattr hooks. When selinux LSM is installed but not initialized, it will list the security.selinux xattr in inode_listsecurity, but will not intercept it in inode_getxattr. This results in -ENODATA for a getxattr call for an xattr returned by listxattr. This situation was manifested as overlayfs failure to copy up lower files from squashfs when selinux is built-in but not initialized, because ovl_copy_xattr() iterates the lower inode xattrs by vfs_listxattr() and vfs_getxattr(). ovl_copy_xattr() skips copy up of security labels that are indentified by inode_copy_up_xattr LSM hooks, but it does that after vfs_getxattr(). Since we are not going to copy them, skip vfs_getxattr() of the security labels. Reported-by:
Michael Labriola <michael.d.labriola@gmail.com> Tested-by:
Michael Labriola <michael.d.labriola@gmail.com> Link: https://lore.kernel.org/linux-unionfs/2nv9d47zt7.fsf@aldarion.sourceruckus.org/ Signed-off-by:
Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Liangyan authored
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: <stable@vger.kernel.org> Fixes: a6c60655 ("ovl: redirect on rename-dir") Signed-off-by:
Liangyan <liangyan.peng@linux.alibaba.com> Reviewed-by:
Joseph Qi <joseph.qi@linux.alibaba.com> Suggested-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
The function ovl_dir_real_file() currently uses the inode lock to serialize writes to the od->upperfile field. However, this function will get called by ovl_ioctl_set_flags(), which utilizes the inode lock too. In this case ovl_dir_real_file() will try to claim a lock that is owned by a function in its call stack, which won't get released before ovl_dir_real_file() returns. Fix by replacing the open coded compare and exchange by an explicit atomic op. Fixes: 61536bed ("ovl: support [S|G]ETFLAGS and FS[S|G]ETXATTR ioctls for directories") Cc: stable@vger.kernel.org # v5.10 Reported-by:
Icenowy Zheng <icenowy@aosc.io> Tested-by:
Icenowy Zheng <icenowy@aosc.io> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
The vfs_getxattr() in ovl_xattr_set() is used to check whether an xattr exist on a lower layer file that is to be removed. If the xattr does not exist, then no need to copy up the file. This call of vfs_getxattr() wasn't wrapped in credential override, and this is probably okay. But for consitency wrap this instance as well. Reported-by:
"Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
Currently there's no way to create an overlay filesystem outside of the current user namespace. Make sure that if this assumption changes it doesn't go unnoticed. Reported-by:
"Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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- Jan 24, 2021
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Christian Brauner authored
Prevent overlayfs from being mounted on top of idmapped mounts. Stacking filesystems need to be prevented from being mounted on top of idmapped mounts until they have have been converted to handle this. Link: https://lore.kernel.org/r/20210121131959.646623-29-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
James Morris <jamorris@linux.microsoft.com> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
Extend some inode methods with an additional user namespace argument. A filesystem that is aware of idmapped mounts will receive the user namespace the mount has been marked with. This can be used for additional permission checking and also to enable filesystems to translate between uids and gids if they need to. We have implemented all relevant helpers in earlier patches. As requested we simply extend the exisiting inode method instead of introducing new ones. This is a little more code churn but it's mostly mechanical and doesnt't leave us with additional inode methods. Link: https://lore.kernel.org/r/20210121131959.646623-25-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
The various vfs_*() helpers are called by filesystems or by the vfs itself to perform core operations such as create, link, mkdir, mknod, rename, rmdir, tmpfile and unlink. Enable them to handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace and pass it down. Afterwards the checks and operations are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-15-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
In order to handle idmapped mounts we will extend the vfs rename helper to take two new arguments in follow up patches. Since this operations already takes a bunch of arguments add a simple struct renamedata and make the current helper use it before we extend it. Link: https://lore.kernel.org/r/20210121131959.646623-14-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Tycho Andersen authored
When interacting with extended attributes the vfs verifies that the caller is privileged over the inode with which the extended attribute is associated. For posix access and posix default extended attributes a uid or gid can be stored on-disk. Let the functions handle posix extended attributes on idmapped mounts. If the inode is accessed through an idmapped mount we need to map it according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. This has no effect for e.g. security xattrs since they don't store uids or gids and don't perform permission checks on them like posix acls do. Link: https://lore.kernel.org/r/20210121131959.646623-10-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
James Morris <jamorris@linux.microsoft.com> Signed-off-by:
Tycho Andersen <tycho@tycho.pizza> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
The posix acl permission checking helpers determine whether a caller is privileged over an inode according to the acls associated with the inode. Add helpers that make it possible to handle acls on idmapped mounts. The vfs and the filesystems targeted by this first iteration make use of posix_acl_fix_xattr_from_user() and posix_acl_fix_xattr_to_user() to translate basic posix access and default permissions such as the ACL_USER and ACL_GROUP type according to the initial user namespace (or the superblock's user namespace) to and from the caller's current user namespace. Adapt these two helpers to handle idmapped mounts whereby we either map from or into the mount's user namespace depending on in which direction we're translating. Similarly, cap_convert_nscap() is used by the vfs to translate user namespace and non-user namespace aware filesystem capabilities from the superblock's user namespace to the caller's user namespace. Enable it to handle idmapped mounts by accounting for the mount's user namespace. In addition the fileystems targeted in the first iteration of this patch series make use of the posix_acl_chmod() and, posix_acl_update_mode() helpers. Both helpers perform permission checks on the target inode. Let them handle idmapped mounts. These two helpers are called when posix acls are set by the respective filesystems to handle this case we extend the ->set() method to take an additional user namespace argument to pass the mount's user namespace down. Link: https://lore.kernel.org/r/20210121131959.646623-9-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
When file attributes are changed most filesystems rely on the setattr_prepare(), setattr_copy(), and notify_change() helpers for initialization and permission checking. Let them handle idmapped mounts. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Helpers that perform checks on the ia_uid and ia_gid fields in struct iattr assume that ia_uid and ia_gid are intended values and have already been mapped correctly at the userspace-kernelspace boundary as we already do today. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-8-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
The inode_owner_or_capable() helper determines whether the caller is the owner of the inode or is capable with respect to that inode. Allow it to handle idmapped mounts. If the inode is accessed through an idmapped mount it according to the mount's user namespace. Afterwards the checks are identical to non-idmapped mounts. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Similarly, allow the inode_init_owner() helper to handle idmapped mounts. It initializes a new inode on idmapped mounts by mapping the fsuid and fsgid of the caller from the mount's user namespace. If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-7-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
James Morris <jamorris@linux.microsoft.com> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
The two helpers inode_permission() and generic_permission() are used by the vfs to perform basic permission checking by verifying that the caller is privileged over an inode. In order to handle idmapped mounts we extend the two helpers with an additional user namespace argument. On idmapped mounts the two helpers will make sure to map the inode according to the mount's user namespace and then peform identical permission checks to inode_permission() and generic_permission(). If the initial user namespace is passed nothing changes so non-idmapped mounts will see identical behavior as before. Link: https://lore.kernel.org/r/20210121131959.646623-6-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
James Morris <jamorris@linux.microsoft.com> Acked-by:
Serge Hallyn <serge@hallyn.com> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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Christian Brauner authored
In order to determine whether a caller holds privilege over a given inode the capability framework exposes the two helpers privileged_wrt_inode_uidgid() and capable_wrt_inode_uidgid(). The former verifies that the inode has a mapping in the caller's user namespace and the latter additionally verifies that the caller has the requested capability in their current user namespace. If the inode is accessed through an idmapped mount map it into the mount's user namespace. Afterwards the checks are identical to non-idmapped inodes. If the initial user namespace is passed all operations are a nop so non-idmapped mounts will not see a change in behavior. Link: https://lore.kernel.org/r/20210121131959.646623-5-christian.brauner@ubuntu.com Cc: Christoph Hellwig <hch@lst.de> Cc: David Howells <dhowells@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Reviewed-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
James Morris <jamorris@linux.microsoft.com> Acked-by:
Serge Hallyn <serge@hallyn.com> Signed-off-by:
Christian Brauner <christian.brauner@ubuntu.com>
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- Dec 14, 2020
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Miklos Szeredi authored
Enable unprivileged user namespace mounts of overlayfs. Overlayfs's permission model (*) ensures that the mounter itself cannot gain additional privileges by the act of creating an overlayfs mount. This feature request is coming from the "rootless" container crowd. (*) Documentation/filesystems/overlayfs.txt#Permission model Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
When looking up an inode on the lower layer for which the mounter lacks read permisison the metacopy check will fail. This causes the lookup to fail as well, even though the directory is readable. So ignore EACCES for the "userxattr" case and assume no metacopy for the unreadable file. Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
In case the file cannot be opened with O_NOATIME because of lack of capabilities, then clear O_NOATIME instead of failing. Remove WARN_ON(), since it would now trigger if O_NOATIME was cleared. Noticed by Amir Goldstein. Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
Comment above call already says this, but only EOPNOTSUPP is ignored, other failures are not. For example setting "user.*" will fail with EPERM on symlink/special. Ignore this error as well. Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
Optionally allow using "user.overlay." namespace instead of "trusted.overlay." This is necessary for overlayfs to be able to be mounted in an unprivileged namepsace. Make the option explicit, since it makes the filesystem format be incompatible. Disable redirect_dir and metacopy options, because these would allow privilege escalation through direct manipulation of the "user.overlay.redirect" or "user.overlay.metacopy" xattrs. Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com> Reviewed-by:
Amir Goldstein <amir73il@gmail.com>
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Miklos Szeredi authored
generic_file_splice_read() and iter_file_splice_write() will call back into f_op->iter_read() and f_op->iter_write() respectively. These already do the real file lookup and cred override. So the code in ovl_splice_read() and ovl_splice_write() is redundant. In addition the ovl_file_accessed() call in ovl_splice_write() is incorrect, though probably harmless. Fix by calling generic_file_splice_read() and iter_file_splice_write() directly. Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
ovl_ioctl_set_flags() does a capability check using flags, but then the real ioctl double-fetches flags and uses potentially different value. The "Check the capability before cred override" comment misleading: user can skip this check by presenting benign flags first and then overwriting them to non-benign flags. Just remove the cred override for now, hoping this doesn't cause a regression. The proper solution is to create a new setxflags i_op (patches are in the works). Xfstests don't show a regression. Reported-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com> Reviewed-by:
Amir Goldstein <amir73il@gmail.com> Fixes: dab5ca8f ("ovl: add lsattr/chattr support") Cc: <stable@vger.kernel.org> # v4.19
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Miklos Szeredi authored
CAP_DAC_READ_SEARCH is required by open_by_handle_at(2) so check it in ovl_decode_real_fh() as well to prevent privilege escalation for unprivileged overlay mounts. [Amir] If the mounter is not capable in init ns, ovl_check_origin() and ovl_verify_index() will not function as expected and this will break index and nfs export features. So check capability in ovl_can_decode_fh(), to auto disable those features. Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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- Nov 12, 2020
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Chengguang Xu authored
In metacopy case, we should use ovl_inode_realdata() instead of ovl_inode_real() to get real inode which has data, so that we can get correct information of extentes in ->fiemap operation. Signed-off-by:
Chengguang Xu <cgxu519@mykernel.net> Reviewed-by:
Amir Goldstein <amir73il@gmail.com> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Miklos Szeredi authored
There was a syzbot report with this warning but insufficient information... Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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Kevin Locke authored
When the lower file of a metacopy is inaccessible, -EIO is returned. For users not familiar with overlayfs internals, such as myself, the meaning of this error may not be apparent or easy to determine, since the (metacopy) file is present and open/stat succeed when accessed outside of the overlay. Add a rate-limited warning for orphan metacopy to give users a hint when investigating such errors. Link: https://lore.kernel.org/linux-unionfs/CAOQ4uxi23Zsmfb4rCed1n=On0NNA5KZD74jjjeyz+et32sk-gg@mail.gmail.com/ Signed-off-by:
Kevin Locke <kevin@kevinlocke.name> Signed-off-by:
Miklos Szeredi <mszeredi@redhat.com>
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