hfsplus: implement POSIX ACLs support

Implement POSIX ACLs support in hfsplus driver.

Signed-off-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 274 insertions, 0 deletions

diff --git a/fs/hfsplus/posix_acl.c b/fs/hfsplus/posix_acl.c
new file mode 100644
index 000000000000..b609cc14c72e
--- /dev/null
+++ b/fs/hfsplus/posix_acl.c
@@ -0,0 +1,274 @@
+/*
+ * linux/fs/hfsplus/posix_acl.c
+ *
+ * Vyacheslav Dubeyko <slava@dubeyko.com>
+ *
+ * Handler for Posix Access Control Lists (ACLs) support.
+ */
+
+#include "hfsplus_fs.h"
+#include "xattr.h"
+#include "acl.h"
+
+struct posix_acl *hfsplus_get_posix_acl(struct inode *inode, int type)
+{
+        struct posix_acl *acl;
+        char *xattr_name;
+        char *value = NULL;
+        ssize_t size;
+
+        acl = get_cached_acl(inode, type);
+        if (acl != ACL_NOT_CACHED)
+                return acl;
+
+        switch (type) {
+        case ACL_TYPE_ACCESS:
+                xattr_name = POSIX_ACL_XATTR_ACCESS;
+                break;
+        case ACL_TYPE_DEFAULT:
+                xattr_name = POSIX_ACL_XATTR_DEFAULT;
+                break;
+        default:
+                return ERR_PTR(-EINVAL);
+        }
+
+        size = __hfsplus_getxattr(inode, xattr_name, NULL, 0);
+
+        if (size > 0) {
+                value = (char *)hfsplus_alloc_attr_entry();
+                if (unlikely(!value))
+                        return ERR_PTR(-ENOMEM);
+                size = __hfsplus_getxattr(inode, xattr_name, value, size);
+        }
+
+        if (size > 0)
+                acl = posix_acl_from_xattr(&init_user_ns, value, size);
+        else if (size == -ENODATA)
+                acl = NULL;
+        else
+                acl = ERR_PTR(size);
+
+        hfsplus_destroy_attr_entry((hfsplus_attr_entry *)value);
+
+        if (!IS_ERR(acl))
+                set_cached_acl(inode, type, acl);
+
+        return acl;
+}
+
+static int hfsplus_set_posix_acl(struct inode *inode,
+                                        int type,
+                                        struct posix_acl *acl)
+{
+        int err;
+        char *xattr_name;
+        size_t size = 0;
+        char *value = NULL;
+
+        if (S_ISLNK(inode->i_mode))
+                return -EOPNOTSUPP;
+
+        switch (type) {
+        case ACL_TYPE_ACCESS:
+                xattr_name = POSIX_ACL_XATTR_ACCESS;
+                if (acl) {
+                        err = posix_acl_equiv_mode(acl, &inode->i_mode);
+                        if (err < 0)
+                                return err;
+                }
+                err = 0;
+                break;
+
+        case ACL_TYPE_DEFAULT:
+                xattr_name = POSIX_ACL_XATTR_DEFAULT;
+                if (!S_ISDIR(inode->i_mode))
+                        return acl ? -EACCES : 0;
+                break;
+
+        default:
+                return -EINVAL;
+        }
+
+        if (acl) {
+                size = posix_acl_xattr_size(acl->a_count);
+                if (unlikely(size > HFSPLUS_MAX_INLINE_DATA_SIZE))
+                        return -ENOMEM;
+                value = (char *)hfsplus_alloc_attr_entry();
+                if (unlikely(!value))
+                        return -ENOMEM;
+                err = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+                if (unlikely(err < 0))
+                        goto end_set_acl;
+        }
+
+        err = __hfsplus_setxattr(inode, xattr_name, value, size, 0);
+
+end_set_acl:
+        hfsplus_destroy_attr_entry((hfsplus_attr_entry *)value);
+
+        if (!err)
+                set_cached_acl(inode, type, acl);
+
+        return err;
+}
+
+int hfsplus_init_posix_acl(struct inode *inode, struct inode *dir)
+{
+        int err = 0;
+        struct posix_acl *acl = NULL;
+
+        hfs_dbg(ACL_MOD,
+                "[%s]: ino %lu, dir->ino %lu\n",
+                __func__, inode->i_ino, dir->i_ino);
+
+        if (S_ISLNK(inode->i_mode))
+                return 0;
+
+        acl = hfsplus_get_posix_acl(dir, ACL_TYPE_DEFAULT);
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+
+        if (acl) {
+                if (S_ISDIR(inode->i_mode)) {
+                        err = hfsplus_set_posix_acl(inode,
+                                                        ACL_TYPE_DEFAULT,
+                                                        acl);
+                        if (unlikely(err))
+                                goto init_acl_cleanup;
+                }
+
+                err = posix_acl_create(&acl, GFP_NOFS, &inode->i_mode);
+                if (unlikely(err < 0))
+                        return err;
+
+                if (err > 0)
+                        err = hfsplus_set_posix_acl(inode,
+                                                        ACL_TYPE_ACCESS,
+                                                        acl);
+        } else
+                inode->i_mode &= ~current_umask();
+
+init_acl_cleanup:
+        posix_acl_release(acl);
+        return err;
+}
+
+int hfsplus_posix_acl_chmod(struct inode *inode)
+{
+        int err;
+        struct posix_acl *acl;
+
+        hfs_dbg(ACL_MOD, "[%s]: ino %lu\n", __func__, inode->i_ino);
+
+        if (S_ISLNK(inode->i_mode))
+                return -EOPNOTSUPP;
+
+        acl = hfsplus_get_posix_acl(inode, ACL_TYPE_ACCESS);
+        if (IS_ERR(acl) || !acl)
+                return PTR_ERR(acl);
+
+        err = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
+        if (unlikely(err))
+                return err;
+
+        err = hfsplus_set_posix_acl(inode, ACL_TYPE_ACCESS, acl);
+        posix_acl_release(acl);
+        return err;
+}
+
+static int hfsplus_xattr_get_posix_acl(struct dentry *dentry,
+                                        const char *name,
+                                        void *buffer,
+                                        size_t size,
+                                        int type)
+{
+        int err = 0;
+        struct posix_acl *acl;
+
+        hfs_dbg(ACL_MOD,
+                "[%s]: ino %lu, buffer %p, size %zu, type %#x\n",
+                __func__, dentry->d_inode->i_ino, buffer, size, type);
+
+        if (strcmp(name, "") != 0)
+                return -EINVAL;
+
+        acl = hfsplus_get_posix_acl(dentry->d_inode, type);
+        if (IS_ERR(acl))
+                return PTR_ERR(acl);
+        if (acl == NULL)
+                return -ENODATA;
+
+        err = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+        posix_acl_release(acl);
+
+        return err;
+}
+
+static int hfsplus_xattr_set_posix_acl(struct dentry *dentry,
+                                        const char *name,
+                                        const void *value,
+                                        size_t size,
+                                        int flags,
+                                        int type)
+{
+        int err = 0;
+        struct inode *inode = dentry->d_inode;
+        struct posix_acl *acl = NULL;
+
+        hfs_dbg(ACL_MOD,
+                "[%s]: ino %lu, value %p, size %zu, flags %#x, type %#x\n",
+                __func__, inode->i_ino, value, size, flags, type);
+
+        if (strcmp(name, "") != 0)
+                return -EINVAL;
+
+        if (!inode_owner_or_capable(inode))
+                return -EPERM;
+
+        if (value) {
+                acl = posix_acl_from_xattr(&init_user_ns, value, size);
+                if (IS_ERR(acl))
+                        return PTR_ERR(acl);
+                else if (acl) {
+                        err = posix_acl_valid(acl);
+                        if (err)
+                                goto end_xattr_set_acl;
+                }
+        }
+
+        err = hfsplus_set_posix_acl(inode, type, acl);
+
+end_xattr_set_acl:
+        posix_acl_release(acl);
+        return err;
+}
+
+static size_t hfsplus_xattr_list_posix_acl(struct dentry *dentry,
+                                                char *list,
+                                                size_t list_size,
+                                                const char *name,
+                                                size_t name_len,
+                                                int type)
+{
+        /*
+         * This method is not used.
+         * It is used hfsplus_listxattr() instead of generic_listxattr().
+         */
+        return -EOPNOTSUPP;
+}
+
+const struct xattr_handler hfsplus_xattr_acl_access_handler = {
+        .prefix = POSIX_ACL_XATTR_ACCESS,
+        .flags  = ACL_TYPE_ACCESS,
+        .list   = hfsplus_xattr_list_posix_acl,
+        .get    = hfsplus_xattr_get_posix_acl,
+        .set    = hfsplus_xattr_set_posix_acl,
+};
+
+const struct xattr_handler hfsplus_xattr_acl_default_handler = {
+        .prefix = POSIX_ACL_XATTR_DEFAULT,
+        .flags  = ACL_TYPE_DEFAULT,
+        .list   = hfsplus_xattr_list_posix_acl,
+        .get    = hfsplus_xattr_get_posix_acl,
+        .set    = hfsplus_xattr_set_posix_acl,
+};