kernel.git/fs/namei.c, branch linux-5.19.y

__follow_mount_rcu(): verify that mount_lock remains unchanged

2022-08-17T13:16:06Z

commit 20aac6c60981f5bfacd66661d090d907bf1482f0 upstream. Validate mount_lock seqcount as soon as we cross into mount in RCU mode. Sure, ->mnt_root is pinned and will remain so until we do rcu_read_unlock() anyway, and we will eventually fail to unlazy if the mount_lock had been touched, but we might run into a hard error (e.g. -ENOENT) before trying to unlazy. And it's possible to end up with RCU pathwalk racing with rename() and umount() in a way that would fail with -ENOENT while non-RCU pathwalk would've succeeded with any timings. Once upon a time we hadn't needed that, but analysis had been subtle, brittle and went out of window as soon as RENAME_EXCHANGE had been added. It's narrow, hard to hit and won't get you anything other than stray -ENOENT that could be arranged in much easier way with the same priveleges, but it's a bug all the same. Cc: stable@kernel.org X-sky-is-falling: unlikely Fixes: da1ce0670c14 "vfs: add cross-rename" Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

fs: Add missing umask strip in vfs_tmpfile

2022-08-17T13:13:47Z

commit ac6800e279a22b28f4fc21439843025a0d5bf03e upstream. All creation paths except for O_TMPFILE handle umask in the vfs directly if the filesystem doesn't support or enable POSIX ACLs. If the filesystem does then umask handling is deferred until posix_acl_create(). Because, O_TMPFILE misses umask handling in the vfs it will not honor umask settings. Fix this by adding the missing umask handling. Link: https://lore.kernel.org/r/1657779088-2242-2-git-send-email-xuyang2018.jy@fujitsu.com Fixes: 60545d0d4610 ("[O_TMPFILE] it's still short a few helpers, but infrastructure should be OK now...") Cc: # 4.19+ Reported-by: Christian Brauner (Microsoft) Reviewed-by: Darrick J. Wong Reviewed-and-Tested-by: Jeff Layton Acked-by: Christian Brauner (Microsoft) Signed-off-by: Yang Xu Signed-off-by: Christian Brauner (Microsoft) Signed-off-by: Greg Kroah-Hartman

Merge tag 'pull-18-rc1-work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2022-06-05T02:07:15Z

Pull vfs pathname updates from Al Viro: "Several cleanups in fs/namei.c" * tag 'pull-18-rc1-work.namei' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: namei: cleanup double word in comment get rid of dead code in legitimize_root() fs/namei.c:reserve_stack(): tidy up the call of try_to_unlazy()

Merge tag 'ovl-update-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs

2022-05-30T18:19:16Z

Pull overlayfs updates from Miklos Szeredi: - Support idmapped layers in overlayfs (Christian Brauner) - Add a fix to exportfs that is relevant to open_by_handle_at(2) as well - Introduce new lookup helpers that allow passing mnt_userns into inode_permission() * tag 'ovl-update-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: ovl: support idmapped layers ovl: handle idmappings in ovl_xattr_{g,s}et() ovl: handle idmappings in layer open helpers ovl: handle idmappings in ovl_permission() ovl: use ovl_copy_{real,upper}attr() wrappers ovl: store lower path in ovl_inode ovl: handle idmappings for layer lookup ovl: handle idmappings for layer fileattrs ovl: use ovl_path_getxattr() wrapper ovl: use ovl_lookup_upper() wrapper ovl: use ovl_do_notify_change() wrapper ovl: pass layer mnt to ovl_open_realfile() ovl: pass ofs to setattr operations ovl: handle idmappings in creation operations ovl: add ovl_upper_mnt_userns() wrapper ovl: pass ofs to creation operations ovl: use wrappers to all vfs_*xattr() calls exportfs: support idmapped mounts fs: add two trivial lookup helpers

Merge tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2022-05-27T18:22:03Z

Pull misc updates from Andrew Morton: "The non-MM patch queue for this merge window. Not a lot of material this cycle. Many singleton patches against various subsystems. Most notably some maintenance work in ocfs2 and initramfs" * tag 'mm-nonmm-stable-2022-05-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (65 commits) kcov: update pos before writing pc in trace function ocfs2: dlmfs: fix error handling of user_dlm_destroy_lock ocfs2: dlmfs: don't clear USER_LOCK_ATTACHED when destroying lock fs/ntfs: remove redundant variable idx fat: remove time truncations in vfat_create/vfat_mkdir fat: report creation time in statx fat: ignore ctime updates, and keep ctime identical to mtime in memory fat: split fat_truncate_time() into separate functions MAINTAINERS: add Muchun as a memcg reviewer proc/sysctl: make protected_* world readable ia64: mca: drop redundant spinlock initialization tty: fix deadlock caused by calling printk() under tty_port->lock relay: remove redundant assignment to pointer buf fs/ntfs3: validate BOOT sectors_per_clusters lib/string_helpers: fix not adding strarray to device's resource list kernel/crash_core.c: remove redundant check of ck_cmdline ELF, uapi: fixup ELF_ST_TYPE definition ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() ipc: update semtimedop() to use hrtimer ipc/sem: remove redundant assignments ...

namei: cleanup double word in comment

2022-05-20T03:26:29Z

Remove the second 'to'. Signed-off-by: Tom Rix Signed-off-by: Al Viro

get rid of dead code in legitimize_root()

2022-05-20T03:26:29Z

Combination of LOOKUP_IS_SCOPED and NULL nd->root.mnt is impossible after successful path_init(). All places where ->root.mnt might become NULL do that only if LOOKUP_IS_SCOPED is not there and path_init() itself can return success without setting nd->root only if ND_ROOT_PRESET had been set (in which case nd->root had been set by caller and never changed) or if the name had been a relative one *and* none of the bits in LOOKUP_IS_SCOPED had been present. Since all calls of legitimize_root() must be downstream of successful path_init(), the check for !nd->root.mnt && (nd->flags & LOOKUP_IS_SCOPED) is pure paranoia. FWIW, it had been discussed (and agreed upon) with Aleksa back when scoped lookups had been merged; looks like that had fallen through the cracks back then. Signed-off-by: Al Viro

fs/namei.c:reserve_stack(): tidy up the call of try_to_unlazy()

2022-05-20T03:26:29Z

!foo() != 0 is a strange way to spell !foo(); fallout from "fs: make unlazy_walk() error handling consistent"... Signed-off-by: Al Viro

proc/sysctl: make protected_* world readable

2022-05-13T23:58:15Z

protected_* files have 600 permissions which prevents non-superuser from reading them. Container like "AWS greengrass" refuse to launch unless protected_hardlinks and protected_symlinks are set. When containers like these run with "userns-remap" or "--user" mapping container's root to non-superuser on host, they fail to run due to denied read access to these files. As these protections are hardly a secret, and do not possess any security risk, making them world readable. Though above greengrass usecase needs read access to only protected_hardlinks and protected_symlinks files, setting all other protected_* files to 644 to keep consistency. Link: http://lkml.kernel.org/r/20200709235115.56954-1-jpitti@cisco.com Fixes: 800179c9b8a1 ("fs: add link restrictions") Signed-off-by: Julius Hemanth Pitti Acked-by: Kees Cook Acked-by: Luis Chamberlain Cc: Iurii Zaikin Cc: Ingo Molnar Cc: Al Viro Signed-off-by: Andrew Morton

namei: Call aops write_begin() and write_end() directly

2022-05-08T18:28:45Z

pagecache_write_begin() and pagecache_write_end() are now trivial wrappers, so call the aops directly. Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig