[PATCH v27 01/21] vfs: Add IS_ACL() and IS_RICHACL() tests

From: Andreas Gruenbacher
Date: Tue Oct 11 2016 - 08:56:26 EST


The vfs does not apply the umask for file systems that support acls.
The test used for this used to be called IS_POSIXACL(). Switch to a new
IS_ACL() test to check for either posix acls or richacls instead. Add a
new MS_RICHACL flag and IS_RICHACL() test for richacls alone. The
IS_POSIXACL() test is still needed in some places like nfsd.

Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Reviewed-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx>
Reviewed-by: Steve French <steve.french@xxxxxxxxxxxxxxx>
Reviewed-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/Kconfig | 3 +++
fs/namei.c | 6 +++---
include/linux/fs.h | 12 ++++++++++++
include/uapi/linux/fs.h | 3 ++-
4 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 4bd03a2..00c6865 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -67,6 +67,9 @@ endif # BLOCK
config FS_POSIX_ACL
def_bool n

+config FS_RICHACL
+ def_bool n
+
config EXPORTFS
tristate

diff --git a/fs/namei.c b/fs/namei.c
index a7f601c..33bdea7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3129,7 +3129,7 @@ static int lookup_open(struct nameidata *nd, struct path *path,
* O_EXCL open we want to return EEXIST not EROFS).
*/
if (open_flag & O_CREAT) {
- if (!IS_POSIXACL(dir->d_inode))
+ if (!IS_ACL(dir->d_inode))
mode &= ~current_umask();
if (unlikely(!got_write)) {
create_error = -EROFS;
@@ -3723,7 +3723,7 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
if (IS_ERR(dentry))
return PTR_ERR(dentry);

- if (!IS_POSIXACL(path.dentry->d_inode))
+ if (!IS_ACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mknod(&path, dentry, mode, dev);
if (error)
@@ -3794,7 +3794,7 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
if (IS_ERR(dentry))
return PTR_ERR(dentry);

- if (!IS_POSIXACL(path.dentry->d_inode))
+ if (!IS_ACL(path.dentry->d_inode))
mode &= ~current_umask();
error = security_path_mkdir(&path, dentry, mode);
if (!error)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index c145219..b88225a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1867,6 +1867,12 @@ struct super_operations {
#define IS_IMMUTABLE(inode) ((inode)->i_flags & S_IMMUTABLE)
#define IS_POSIXACL(inode) __IS_FLG(inode, MS_POSIXACL)

+#ifdef CONFIG_FS_RICHACL
+#define IS_RICHACL(inode) __IS_FLG(inode, MS_RICHACL)
+#else
+#define IS_RICHACL(inode) 0
+#endif
+
#define IS_DEADDIR(inode) ((inode)->i_flags & S_DEAD)
#define IS_NOCMTIME(inode) ((inode)->i_flags & S_NOCMTIME)
#define IS_SWAPFILE(inode) ((inode)->i_flags & S_SWAPFILE)
@@ -1885,6 +1891,12 @@ static inline bool HAS_UNMAPPED_ID(struct inode *inode)
}

/*
+ * IS_ACL() tells the VFS to not apply the umask
+ * and use check_acl for acl permission checks when defined.
+ */
+#define IS_ACL(inode) __IS_FLG(inode, MS_POSIXACL | MS_RICHACL)
+
+/*
* Inode state bits. Protected by inode->i_lock
*
* Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h
index 2473272..0514d90 100644
--- a/include/uapi/linux/fs.h
+++ b/include/uapi/linux/fs.h
@@ -120,7 +120,7 @@ struct inodes_stat_t {
#define MS_VERBOSE 32768 /* War is peace. Verbosity is silence.
MS_VERBOSE is deprecated. */
#define MS_SILENT 32768
-#define MS_POSIXACL (1<<16) /* VFS does not apply the umask */
+#define MS_POSIXACL (1<<16) /* Supports POSIX ACLs */
#define MS_UNBINDABLE (1<<17) /* change to unbindable */
#define MS_PRIVATE (1<<18) /* change to private */
#define MS_SLAVE (1<<19) /* change to slave */
@@ -130,6 +130,7 @@ struct inodes_stat_t {
#define MS_I_VERSION (1<<23) /* Update inode I_version field */
#define MS_STRICTATIME (1<<24) /* Always perform atime updates */
#define MS_LAZYTIME (1<<25) /* Update the on-disk [acm]times lazily */
+#define MS_RICHACL (1<<26) /* Supports richacls */

/* These sb flags are internal to the kernel */
#define MS_NOREMOTELOCK (1<<27)
--
2.7.4