1 files changed, 345 insertions, 0 deletions
diff --git a/fs/9p/acl.c b/fs/9p/acl.c
new file mode 100644
index 0000000000..eed551d855
--- /dev/null
+++ b/fs/9p/acl.c
@@ -0,0 +1,345 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <net/9p/9p.h>
+#include <net/9p/client.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/posix_acl_xattr.h>
+#include "xattr.h"
+#include "acl.h"
+#include "v9fs.h"
+#include "v9fs_vfs.h"
+#include "fid.h"
+
+static struct posix_acl *v9fs_fid_get_acl(struct p9_fid *fid, const char *name)
+{
+	ssize_t size;
+	void *value = NULL;
+	struct posix_acl *acl = NULL;
+
+	size = v9fs_fid_xattr_get(fid, name, NULL, 0);
+	if (size < 0)
+		return ERR_PTR(size);
+	if (size == 0)
+		return ERR_PTR(-ENODATA);
+
+	value = kzalloc(size, GFP_NOFS);
+	if (!value)
+		return ERR_PTR(-ENOMEM);
+
+	size = v9fs_fid_xattr_get(fid, name, value, size);
+	if (size < 0)
+		acl = ERR_PTR(size);
+	else if (size == 0)
+		acl = ERR_PTR(-ENODATA);
+	else
+		acl = posix_acl_from_xattr(&init_user_ns, value, size);
+	kfree(value);
+	return acl;
+}
+
+static struct posix_acl *v9fs_acl_get(struct dentry *dentry, const char *name)
+{
+	struct p9_fid *fid;
+	struct posix_acl *acl = NULL;
+
+	fid = v9fs_fid_lookup(dentry);
+	if (IS_ERR(fid))
+		return ERR_CAST(fid);
+
+	acl = v9fs_fid_get_acl(fid, name);
+	p9_fid_put(fid);
+	return acl;
+}
+
+static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, const char *name)
+{
+	int retval;
+	struct posix_acl *acl = NULL;
+
+	acl = v9fs_fid_get_acl(fid, name);
+	if (!IS_ERR(acl))
+		return acl;
+
+	retval = PTR_ERR(acl);
+	if (retval == -ENODATA || retval == -ENOSYS || retval == -EOPNOTSUPP)
+		return NULL;
+
+	/* map everything else to -EIO */
+	return ERR_PTR(-EIO);
+}
+
+int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
+{
+	int retval = 0;
+	struct posix_acl *pacl, *dacl;
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_inode2v9ses(inode);
+	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
+			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
+		set_cached_acl(inode, ACL_TYPE_DEFAULT, NULL);
+		set_cached_acl(inode, ACL_TYPE_ACCESS, NULL);
+		return 0;
+	}
+	/* get the default/access acl values and cache them */
+	dacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_DEFAULT);
+	pacl = __v9fs_get_acl(fid, XATTR_NAME_POSIX_ACL_ACCESS);
+
+	if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
+		set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
+		set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
+	} else
+		retval = -EIO;
+
+	if (!IS_ERR(dacl))
+		posix_acl_release(dacl);
+
+	if (!IS_ERR(pacl))
+		posix_acl_release(pacl);
+
+	return retval;
+}
+
+static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
+{
+	struct posix_acl *acl;
+	/*
+	 * 9p Always cache the acl value when
+	 * instantiating the inode (v9fs_inode_from_fid)
+	 */
+	acl = get_cached_acl(inode, type);
+	BUG_ON(is_uncached_acl(acl));
+	return acl;
+}
+
+struct posix_acl *v9fs_iop_get_inode_acl(struct inode *inode, int type, bool rcu)
+{
+	struct v9fs_session_info *v9ses;
+
+	if (rcu)
+		return ERR_PTR(-ECHILD);
+
+	v9ses = v9fs_inode2v9ses(inode);
+	if (((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) ||
+			((v9ses->flags & V9FS_ACL_MASK) != V9FS_POSIX_ACL)) {
+		/*
+		 * On access = client  and acl = on mode get the acl
+		 * values from the server
+		 */
+		return NULL;
+	}
+	return v9fs_get_cached_acl(inode, type);
+
+}
+
+struct posix_acl *v9fs_iop_get_acl(struct mnt_idmap *idmap,
+				   struct dentry *dentry, int type)
+{
+	struct v9fs_session_info *v9ses;
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	/* We allow set/get/list of acl when access=client is not specified. */
+	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT)
+		return v9fs_acl_get(dentry, posix_acl_xattr_name(type));
+	return v9fs_get_cached_acl(d_inode(dentry), type);
+}
+
+int v9fs_iop_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
+		     struct posix_acl *acl, int type)
+{
+	int retval;
+	size_t size = 0;
+	void *value = NULL;
+	const char *acl_name;
+	struct v9fs_session_info *v9ses;
+	struct inode *inode = d_inode(dentry);
+
+	if (acl) {
+		retval = posix_acl_valid(inode->i_sb->s_user_ns, acl);
+		if (retval)
+			goto err_out;
+
+		size = posix_acl_xattr_size(acl->a_count);
+
+		value = kzalloc(size, GFP_NOFS);
+		if (!value) {
+			retval = -ENOMEM;
+			goto err_out;
+		}
+
+		retval = posix_acl_to_xattr(&init_user_ns, acl, value, size);
+		if (retval < 0)
+			goto err_out;
+	}
+
+	/*
+	 * set the attribute on the remote. Without even looking at the
+	 * xattr value. We leave it to the server to validate
+	 */
+	acl_name = posix_acl_xattr_name(type);
+	v9ses = v9fs_dentry2v9ses(dentry);
+	if ((v9ses->flags & V9FS_ACCESS_MASK) != V9FS_ACCESS_CLIENT) {
+		retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
+		goto err_out;
+	}
+
+	if (S_ISLNK(inode->i_mode)) {
+		retval = -EOPNOTSUPP;
+		goto err_out;
+	}
+
+	if (!inode_owner_or_capable(&nop_mnt_idmap, inode)) {
+		retval = -EPERM;
+		goto err_out;
+	}
+
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		if (acl) {
+			struct iattr iattr = {};
+			struct posix_acl *acl_mode = acl;
+
+			retval = posix_acl_update_mode(&nop_mnt_idmap, inode,
+						       &iattr.ia_mode,
+						       &acl_mode);
+			if (retval)
+				goto err_out;
+			if (!acl_mode) {
+				/*
+				 * ACL can be represented by the mode bits.
+				 * So don't update ACL below.
+				 */
+				kfree(value);
+				value = NULL;
+				size = 0;
+			}
+			iattr.ia_valid = ATTR_MODE;
+			/*
+			 * FIXME should we update ctime ?
+			 * What is the following setxattr update the mode ?
+			 */
+			v9fs_vfs_setattr_dotl(&nop_mnt_idmap, dentry, &iattr);
+		}
+		break;
+	case ACL_TYPE_DEFAULT:
+		if (!S_ISDIR(inode->i_mode)) {
+			retval = acl ? -EINVAL : 0;
+			goto err_out;
+		}
+		break;
+	}
+
+	retval = v9fs_xattr_set(dentry, acl_name, value, size, 0);
+	if (!retval)
+		set_cached_acl(inode, type, acl);
+
+err_out:
+	kfree(value);
+	return retval;
+}
+
+static int v9fs_set_acl(struct p9_fid *fid, int type, struct posix_acl *acl)
+{
+	int retval;
+	char *name;
+	size_t size;
+	void *buffer;
+
+	if (!acl)
+		return 0;
+
+	/* Set a setxattr request to server */
+	size = posix_acl_xattr_size(acl->a_count);
+	buffer = kmalloc(size, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+	retval = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
+	if (retval < 0)
+		goto err_free_out;
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name = XATTR_NAME_POSIX_ACL_ACCESS;
+		break;
+	case ACL_TYPE_DEFAULT:
+		name = XATTR_NAME_POSIX_ACL_DEFAULT;
+		break;
+	default:
+		BUG();
+	}
+	retval = v9fs_fid_xattr_set(fid, name, buffer, size, 0);
+err_free_out:
+	kfree(buffer);
+	return retval;
+}
+
+int v9fs_acl_chmod(struct inode *inode, struct p9_fid *fid)
+{
+	int retval = 0;
+	struct posix_acl *acl;
+
+	if (S_ISLNK(inode->i_mode))
+		return -EOPNOTSUPP;
+	acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
+	if (acl) {
+		retval = __posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode);
+		if (retval)
+			return retval;
+		set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
+		retval = v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
+		posix_acl_release(acl);
+	}
+	return retval;
+}
+
+int v9fs_set_create_acl(struct inode *inode, struct p9_fid *fid,
+			struct posix_acl *dacl, struct posix_acl *acl)
+{
+	set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
+	set_cached_acl(inode, ACL_TYPE_ACCESS, acl);
+	v9fs_set_acl(fid, ACL_TYPE_DEFAULT, dacl);
+	v9fs_set_acl(fid, ACL_TYPE_ACCESS, acl);
+	return 0;
+}
+
+void v9fs_put_acl(struct posix_acl *dacl,
+		  struct posix_acl *acl)
+{
+	posix_acl_release(dacl);
+	posix_acl_release(acl);
+}
+
+int v9fs_acl_mode(struct inode *dir, umode_t *modep,
+		  struct posix_acl **dpacl, struct posix_acl **pacl)
+{
+	int retval = 0;
+	umode_t mode = *modep;
+	struct posix_acl *acl = NULL;
+
+	if (!S_ISLNK(mode)) {
+		acl = v9fs_get_cached_acl(dir, ACL_TYPE_DEFAULT);
+		if (IS_ERR(acl))
+			return PTR_ERR(acl);
+		if (!acl)
+			mode &= ~current_umask();
+	}
+	if (acl) {
+		if (S_ISDIR(mode))
+			*dpacl = posix_acl_dup(acl);
+		retval = __posix_acl_create(&acl, GFP_NOFS, &mode);
+		if (retval < 0)
+			return retval;
+		if (retval > 0)
+			*pacl = acl;
+		else
+			posix_acl_release(acl);
+	}
+	*modep  = mode;
+	return 0;
+}