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| author | Jeff Layton <jlayton@kernel.org> | 2023-09-11 20:25:50 -0400 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2023-10-19 11:02:47 +0200 |
| commit | 5aa8fd9cea2ee0d42c5d92c5eacf0a14bbc4c293 (patch) | |
| tree | 055147b2649fad285c863547c41cba7d766761bc /include | |
| parent | 84d2b696236c63836011f04d13d3f09ed47fa560 (diff) | |
| download | lwn-5aa8fd9cea2ee0d42c5d92c5eacf0a14bbc4c293.tar.gz lwn-5aa8fd9cea2ee0d42c5d92c5eacf0a14bbc4c293.zip | |
fs: add a new SB_I_NOUMASK flag
SB_POSIXACL must be set when a filesystem supports POSIX ACLs, but NFSv4
also sets this flag to prevent the VFS from applying the umask on
newly-created files. NFSv4 doesn't support POSIX ACLs however, which
causes confusion when other subsystems try to test for them.
Add a new SB_I_NOUMASK flag that allows filesystems to opt-in to umask
stripping without advertising support for POSIX ACLs. Set the new flag
on NFSv4 instead of SB_POSIXACL.
Also, move mode_strip_umask to namei.h and convert init_mknod and
init_mkdir to use it.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Message-Id: <20230911-acl-fix-v3-1-b25315333f6c@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/fs.h | 3 | ||||
| -rw-r--r-- | include/linux/namei.h | 24 |
2 files changed, 26 insertions, 1 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 4aeb3fa11927..58dea591a341 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1119,7 +1119,7 @@ extern int send_sigurg(struct fown_struct *fown); #define SB_NOATIME BIT(10) /* Do not update access times. */ #define SB_NODIRATIME BIT(11) /* Do not update directory access times */ #define SB_SILENT BIT(15) -#define SB_POSIXACL BIT(16) /* VFS does not apply the umask */ +#define SB_POSIXACL BIT(16) /* Supports POSIX ACLs */ #define SB_INLINECRYPT BIT(17) /* Use blk-crypto for encrypted files */ #define SB_KERNMOUNT BIT(22) /* this is a kern_mount call */ #define SB_I_VERSION BIT(23) /* Update inode I_version field */ @@ -1166,6 +1166,7 @@ extern int send_sigurg(struct fown_struct *fown); #define SB_I_PERSB_BDI 0x00000200 /* has a per-sb bdi */ #define SB_I_TS_EXPIRY_WARNED 0x00000400 /* warned about timestamp range expiry */ #define SB_I_RETIRED 0x00000800 /* superblock shouldn't be reused */ +#define SB_I_NOUMASK 0x00001000 /* VFS does not apply umask */ /* Possible states of 'frozen' field */ enum { diff --git a/include/linux/namei.h b/include/linux/namei.h index 1463cbda4888..e3619920f9f0 100644 --- a/include/linux/namei.h +++ b/include/linux/namei.h @@ -92,6 +92,30 @@ extern struct dentry *lock_rename(struct dentry *, struct dentry *); extern struct dentry *lock_rename_child(struct dentry *, struct dentry *); extern void unlock_rename(struct dentry *, struct dentry *); +/** + * mode_strip_umask - handle vfs umask stripping + * @dir: parent directory of the new inode + * @mode: mode of the new inode to be created in @dir + * + * In most filesystems, umask stripping depends on whether or not the + * filesystem supports POSIX ACLs. If the filesystem doesn't support it umask + * stripping is done directly in here. If the filesystem does support POSIX + * ACLs umask stripping is deferred until the filesystem calls + * posix_acl_create(). + * + * Some filesystems (like NFSv4) also want to avoid umask stripping by the + * VFS, but don't support POSIX ACLs. Those filesystems can set SB_I_NOUMASK + * to get this effect without declaring that they support POSIX ACLs. + * + * Returns: mode + */ +static inline umode_t __must_check mode_strip_umask(const struct inode *dir, umode_t mode) +{ + if (!IS_POSIXACL(dir) && !(dir->i_sb->s_iflags & SB_I_NOUMASK)) + mode &= ~current_umask(); + return mode; +} + extern int __must_check nd_jump_link(const struct path *path); static inline void nd_terminate_link(void *name, size_t len, size_t maxlen) |