fs/afs/xattr.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /* Extended attribute handling for AFS.  We use xattrs to get and set metadata
  * instead of providing pioctl().
  *
  * Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
  * Written by David Howells (dhowells@redhat.com)
  */

 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/xattr.h>
 #include "internal.h"

 /*
  * Deal with the result of a successful fetch ACL operation.
  */
 static void afs_acl_success(struct afs_operation *op)
 {
 	afs_vnode_commit_status(op, &op->file[0]);
 }

 static void afs_acl_put(struct afs_operation *op)
 {
 	kfree(op->acl);
 }

 static const struct afs_operation_ops afs_fetch_acl_operation = {
 	.issue_afs_rpc	= afs_fs_fetch_acl,
 	.success	= afs_acl_success,
 	.put		= afs_acl_put,
 };

 /*
  * Get a file's ACL.
  */
 static int afs_xattr_get_acl(const struct xattr_handler *handler,
 			     struct dentry *dentry,
 			     struct inode *inode, const char *name,
 			     void *buffer, size_t size)
 {
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	struct afs_acl *acl = NULL;
 	int ret;

 	op = afs_alloc_operation(NULL, vnode->volume);
 	if (IS_ERR(op))
 		return -ENOMEM;

 	afs_op_set_vnode(op, 0, vnode);
 	op->ops = &afs_fetch_acl_operation;

 	afs_begin_vnode_operation(op);
 	afs_wait_for_operation(op);
 	acl = op->acl;
 	op->acl = NULL;
 	ret = afs_put_operation(op);

 	if (ret == 0) {
 		ret = acl->size;
 		if (size > 0) {
 			if (acl->size <= size)
 				memcpy(buffer, acl->data, acl->size);
 			else
 				ret = -ERANGE;
 		}
 	}

 	kfree(acl);
 	return ret;
 }

 static bool afs_make_acl(struct afs_operation *op,
 			 const void *buffer, size_t size)
 {
 	struct afs_acl *acl;

 	acl = kmalloc(sizeof(*acl) + size, GFP_KERNEL);
 	if (!acl) {
 		afs_op_nomem(op);
 		return false;
 	}

 	acl->size = size;
 	memcpy(acl->data, buffer, size);
 	op->acl = acl;
 	return true;
 }

 static const struct afs_operation_ops afs_store_acl_operation = {
 	.issue_afs_rpc	= afs_fs_store_acl,
 	.success	= afs_acl_success,
 	.put		= afs_acl_put,
 };

 /*
  * Set a file's AFS3 ACL.
  */
 static int afs_xattr_set_acl(const struct xattr_handler *handler,
 			     struct user_namespace *mnt_userns,
                              struct dentry *dentry,
                              struct inode *inode, const char *name,
                              const void *buffer, size_t size, int flags)
 {
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(inode);

 	if (flags == XATTR_CREATE)
 		return -EINVAL;

 	op = afs_alloc_operation(NULL, vnode->volume);
 	if (IS_ERR(op))
 		return -ENOMEM;

 	afs_op_set_vnode(op, 0, vnode);
 	if (!afs_make_acl(op, buffer, size))
 		return afs_put_operation(op);

 	op->ops = &afs_store_acl_operation;
 	return afs_do_sync_operation(op);
 }

 static const struct xattr_handler afs_xattr_afs_acl_handler = {
 	.name   = "afs.acl",
 	.get    = afs_xattr_get_acl,
 	.set    = afs_xattr_set_acl,
 };

 static const struct afs_operation_ops yfs_fetch_opaque_acl_operation = {
 	.issue_yfs_rpc	= yfs_fs_fetch_opaque_acl,
 	.success	= afs_acl_success,
 	/* Don't free op->yacl in .put here */
 };

 /*
  * Get a file's YFS ACL.
  */
 static int afs_xattr_get_yfs(const struct xattr_handler *handler,
 			     struct dentry *dentry,
 			     struct inode *inode, const char *name,
 			     void *buffer, size_t size)
 {
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	struct yfs_acl *yacl = NULL;
 	char buf[16], *data;
 	int which = 0, dsize, ret = -ENOMEM;

 	if (strcmp(name, "acl") == 0)
 		which = 0;
 	else if (strcmp(name, "acl_inherited") == 0)
 		which = 1;
 	else if (strcmp(name, "acl_num_cleaned") == 0)
 		which = 2;
 	else if (strcmp(name, "vol_acl") == 0)
 		which = 3;
 	else
 		return -EOPNOTSUPP;

 	yacl = kzalloc(sizeof(struct yfs_acl), GFP_KERNEL);
 	if (!yacl)
 		goto error;

 	if (which == 0)
 		yacl->flags |= YFS_ACL_WANT_ACL;
 	else if (which == 3)
 		yacl->flags |= YFS_ACL_WANT_VOL_ACL;

 	op = afs_alloc_operation(NULL, vnode->volume);
 	if (IS_ERR(op))
 		goto error_yacl;

 	afs_op_set_vnode(op, 0, vnode);
 	op->yacl = yacl;
 	op->ops = &yfs_fetch_opaque_acl_operation;

 	afs_begin_vnode_operation(op);
 	afs_wait_for_operation(op);
 	ret = afs_put_operation(op);

 	if (ret == 0) {
 		switch (which) {
 		case 0:
 			data = yacl->acl->data;
 			dsize = yacl->acl->size;
 			break;
 		case 1:
 			data = buf;
 			dsize = scnprintf(buf, sizeof(buf), "%u", yacl->inherit_flag);
 			break;
 		case 2:
 			data = buf;
 			dsize = scnprintf(buf, sizeof(buf), "%u", yacl->num_cleaned);
 			break;
 		case 3:
 			data = yacl->vol_acl->data;
 			dsize = yacl->vol_acl->size;
 			break;
 		default:
 			ret = -EOPNOTSUPP;
 			goto error_yacl;
 		}

 		ret = dsize;
 		if (size > 0) {
 			if (dsize <= size)
 				memcpy(buffer, data, dsize);
 			else
 				ret = -ERANGE;
 		}
 	} else if (ret == -ENOTSUPP) {
 		ret = -ENODATA;
 	}

 error_yacl:
 	yfs_free_opaque_acl(yacl);
 error:
 	return ret;
 }

 static const struct afs_operation_ops yfs_store_opaque_acl2_operation = {
 	.issue_yfs_rpc	= yfs_fs_store_opaque_acl2,
 	.success	= afs_acl_success,
 	.put		= afs_acl_put,
 };

 /*
  * Set a file's YFS ACL.
  */
 static int afs_xattr_set_yfs(const struct xattr_handler *handler,
 			     struct user_namespace *mnt_userns,
                              struct dentry *dentry,
                              struct inode *inode, const char *name,
                              const void *buffer, size_t size, int flags)
 {
 	struct afs_operation *op;
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	int ret;

 	if (flags == XATTR_CREATE ||
 	    strcmp(name, "acl") != 0)
 		return -EINVAL;

 	op = afs_alloc_operation(NULL, vnode->volume);
 	if (IS_ERR(op))
 		return -ENOMEM;

 	afs_op_set_vnode(op, 0, vnode);
 	if (!afs_make_acl(op, buffer, size))
 		return afs_put_operation(op);

 	op->ops = &yfs_store_opaque_acl2_operation;
 	ret = afs_do_sync_operation(op);
 	if (ret == -ENOTSUPP)
 		ret = -ENODATA;
 	return ret;
 }

 static const struct xattr_handler afs_xattr_yfs_handler = {
 	.prefix	= "afs.yfs.",
 	.get	= afs_xattr_get_yfs,
 	.set	= afs_xattr_set_yfs,
 };

 /*
  * Get the name of the cell on which a file resides.
  */
 static int afs_xattr_get_cell(const struct xattr_handler *handler,
 			      struct dentry *dentry,
 			      struct inode *inode, const char *name,
 			      void *buffer, size_t size)
 {
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	struct afs_cell *cell = vnode->volume->cell;
 	size_t namelen;

 	namelen = cell->name_len;
 	if (size == 0)
 		return namelen;
 	if (namelen > size)
 		return -ERANGE;
 	memcpy(buffer, cell->name, namelen);
 	return namelen;
 }

 static const struct xattr_handler afs_xattr_afs_cell_handler = {
 	.name	= "afs.cell",
 	.get	= afs_xattr_get_cell,
 };

 /*
  * Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of
  * hex numbers separated by colons.
  */
 static int afs_xattr_get_fid(const struct xattr_handler *handler,
 			     struct dentry *dentry,
 			     struct inode *inode, const char *name,
 			     void *buffer, size_t size)
 {
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	char text[16 + 1 + 24 + 1 + 8 + 1];
 	size_t len;

 	/* The volume ID is 64-bit, the vnode ID is 96-bit and the
 	 * uniquifier is 32-bit.
 	 */
 	len = scnprintf(text, sizeof(text), "%llx:", vnode->fid.vid);
 	if (vnode->fid.vnode_hi)
 		len += scnprintf(text + len, sizeof(text) - len, "%x%016llx",
 				vnode->fid.vnode_hi, vnode->fid.vnode);
 	else
 		len += scnprintf(text + len, sizeof(text) - len, "%llx",
 				 vnode->fid.vnode);
 	len += scnprintf(text + len, sizeof(text) - len, ":%x",
 			 vnode->fid.unique);

 	if (size == 0)
 		return len;
 	if (len > size)
 		return -ERANGE;
 	memcpy(buffer, text, len);
 	return len;
 }

 static const struct xattr_handler afs_xattr_afs_fid_handler = {
 	.name	= "afs.fid",
 	.get	= afs_xattr_get_fid,
 };

 /*
  * Get the name of the volume on which a file resides.
  */
 static int afs_xattr_get_volume(const struct xattr_handler *handler,
 			      struct dentry *dentry,
 			      struct inode *inode, const char *name,
 			      void *buffer, size_t size)
 {
 	struct afs_vnode *vnode = AFS_FS_I(inode);
 	const char *volname = vnode->volume->name;
 	size_t namelen;

 	namelen = strlen(volname);
 	if (size == 0)
 		return namelen;
 	if (namelen > size)
 		return -ERANGE;
 	memcpy(buffer, volname, namelen);
 	return namelen;
 }

 static const struct xattr_handler afs_xattr_afs_volume_handler = {
 	.name	= "afs.volume",
 	.get	= afs_xattr_get_volume,
 };

 const struct xattr_handler *afs_xattr_handlers[] = {
 	&afs_xattr_afs_acl_handler,
 	&afs_xattr_afs_cell_handler,
 	&afs_xattr_afs_fid_handler,
 	&afs_xattr_afs_volume_handler,
 	&afs_xattr_yfs_handler,		/* afs.yfs. prefix */
 	NULL
 };
	// SPDX-License-Identifier: GPL-2.0-or-later
	/* Extended attribute handling for AFS. We use xattrs to get and set metadata
	* instead of providing pioctl().
	*
	* Copyright (C) 2017 Red Hat, Inc. All Rights Reserved.
	* Written by David Howells (dhowells@redhat.com)
	*/

	#include <linux/slab.h>
	#include <linux/fs.h>
	#include <linux/xattr.h>
	#include "internal.h"

	/*
	* Deal with the result of a successful fetch ACL operation.
	*/
	static void afs_acl_success(struct afs_operation *op)
	{
	afs_vnode_commit_status(op, &op->file[0]);
	}

	static void afs_acl_put(struct afs_operation *op)
	{
	kfree(op->acl);
	}

	static const struct afs_operation_ops afs_fetch_acl_operation = {
	.issue_afs_rpc = afs_fs_fetch_acl,
	.success = afs_acl_success,
	.put = afs_acl_put,
	};

	/*
	* Get a file's ACL.
	*/
	static int afs_xattr_get_acl(const struct xattr_handler *handler,
	struct dentry *dentry,
	struct inode inode, const char name,
	void *buffer, size_t size)
	{
	struct afs_operation *op;
	struct afs_vnode *vnode = AFS_FS_I(inode);
	struct afs_acl *acl = NULL;
	int ret;

	op = afs_alloc_operation(NULL, vnode->volume);
	if (IS_ERR(op))
	return -ENOMEM;

	afs_op_set_vnode(op, 0, vnode);
	op->ops = &afs_fetch_acl_operation;

	afs_begin_vnode_operation(op);
	afs_wait_for_operation(op);
	acl = op->acl;
	op->acl = NULL;
	ret = afs_put_operation(op);

	if (ret == 0) {
	ret = acl->size;
	if (size > 0) {
	if (acl->size <= size)
	memcpy(buffer, acl->data, acl->size);
	else
	ret = -ERANGE;
	}
	}

	kfree(acl);
	return ret;
	}

	static bool afs_make_acl(struct afs_operation *op,
	const void *buffer, size_t size)
	{
	struct afs_acl *acl;

	acl = kmalloc(sizeof(*acl) + size, GFP_KERNEL);
	if (!acl) {
	afs_op_nomem(op);
	return false;
	}

	acl->size = size;
	memcpy(acl->data, buffer, size);
	op->acl = acl;
	return true;
	}

	static const struct afs_operation_ops afs_store_acl_operation = {
	.issue_afs_rpc = afs_fs_store_acl,
	.success = afs_acl_success,
	.put = afs_acl_put,
	};

	/*
	* Set a file's AFS3 ACL.
	*/
	static int afs_xattr_set_acl(const struct xattr_handler *handler,
	struct user_namespace *mnt_userns,
	struct dentry *dentry,
	struct inode inode, const char name,
	const void *buffer, size_t size, int flags)
	{
	struct afs_operation *op;
	struct afs_vnode *vnode = AFS_FS_I(inode);

	if (flags == XATTR_CREATE)
	return -EINVAL;

	op = afs_alloc_operation(NULL, vnode->volume);
	if (IS_ERR(op))
	return -ENOMEM;

	afs_op_set_vnode(op, 0, vnode);
	if (!afs_make_acl(op, buffer, size))
	return afs_put_operation(op);

	op->ops = &afs_store_acl_operation;
	return afs_do_sync_operation(op);
	}

	static const struct xattr_handler afs_xattr_afs_acl_handler = {
	.name = "afs.acl",
	.get = afs_xattr_get_acl,
	.set = afs_xattr_set_acl,
	};

	static const struct afs_operation_ops yfs_fetch_opaque_acl_operation = {
	.issue_yfs_rpc = yfs_fs_fetch_opaque_acl,
	.success = afs_acl_success,
	/* Don't free op->yacl in .put here */
	};

	/*
	* Get a file's YFS ACL.
	*/
	static int afs_xattr_get_yfs(const struct xattr_handler *handler,
	struct dentry *dentry,
	struct inode inode, const char name,
	void *buffer, size_t size)
	{
	struct afs_operation *op;
	struct afs_vnode *vnode = AFS_FS_I(inode);
	struct yfs_acl *yacl = NULL;
	char buf[16], *data;
	int which = 0, dsize, ret = -ENOMEM;

	if (strcmp(name, "acl") == 0)
	which = 0;
	else if (strcmp(name, "acl_inherited") == 0)
	which = 1;
	else if (strcmp(name, "acl_num_cleaned") == 0)
	which = 2;
	else if (strcmp(name, "vol_acl") == 0)
	which = 3;
	else
	return -EOPNOTSUPP;

	yacl = kzalloc(sizeof(struct yfs_acl), GFP_KERNEL);
	if (!yacl)
	goto error;

	if (which == 0)
	yacl->flags \|= YFS_ACL_WANT_ACL;
	else if (which == 3)
	yacl->flags \|= YFS_ACL_WANT_VOL_ACL;

	op = afs_alloc_operation(NULL, vnode->volume);
	if (IS_ERR(op))
	goto error_yacl;

	afs_op_set_vnode(op, 0, vnode);
	op->yacl = yacl;
	op->ops = &yfs_fetch_opaque_acl_operation;

	afs_begin_vnode_operation(op);
	afs_wait_for_operation(op);
	ret = afs_put_operation(op);

	if (ret == 0) {
	switch (which) {
	case 0:
	data = yacl->acl->data;
	dsize = yacl->acl->size;
	break;
	case 1:
	data = buf;
	dsize = scnprintf(buf, sizeof(buf), "%u", yacl->inherit_flag);
	break;
	case 2:
	data = buf;
	dsize = scnprintf(buf, sizeof(buf), "%u", yacl->num_cleaned);
	break;
	case 3:
	data = yacl->vol_acl->data;
	dsize = yacl->vol_acl->size;
	break;
	default:
	ret = -EOPNOTSUPP;
	goto error_yacl;
	}

	ret = dsize;
	if (size > 0) {
	if (dsize <= size)
	memcpy(buffer, data, dsize);
	else
	ret = -ERANGE;
	}
	} else if (ret == -ENOTSUPP) {
	ret = -ENODATA;
	}

	error_yacl:
	yfs_free_opaque_acl(yacl);
	error:
	return ret;
	}

	static const struct afs_operation_ops yfs_store_opaque_acl2_operation = {
	.issue_yfs_rpc = yfs_fs_store_opaque_acl2,
	.success = afs_acl_success,
	.put = afs_acl_put,
	};

	/*
	* Set a file's YFS ACL.
	*/
	static int afs_xattr_set_yfs(const struct xattr_handler *handler,
	struct user_namespace *mnt_userns,
	struct dentry *dentry,
	struct inode inode, const char name,
	const void *buffer, size_t size, int flags)
	{
	struct afs_operation *op;
	struct afs_vnode *vnode = AFS_FS_I(inode);
	int ret;

	if (flags == XATTR_CREATE \|\|
	strcmp(name, "acl") != 0)
	return -EINVAL;

	op = afs_alloc_operation(NULL, vnode->volume);
	if (IS_ERR(op))
	return -ENOMEM;

	afs_op_set_vnode(op, 0, vnode);
	if (!afs_make_acl(op, buffer, size))
	return afs_put_operation(op);

	op->ops = &yfs_store_opaque_acl2_operation;
	ret = afs_do_sync_operation(op);
	if (ret == -ENOTSUPP)
	ret = -ENODATA;
	return ret;
	}

	static const struct xattr_handler afs_xattr_yfs_handler = {
	.prefix = "afs.yfs.",
	.get = afs_xattr_get_yfs,
	.set = afs_xattr_set_yfs,
	};

	/*
	* Get the name of the cell on which a file resides.
	*/
	static int afs_xattr_get_cell(const struct xattr_handler *handler,
	struct dentry *dentry,
	struct inode inode, const char name,
	void *buffer, size_t size)
	{
	struct afs_vnode *vnode = AFS_FS_I(inode);
	struct afs_cell *cell = vnode->volume->cell;
	size_t namelen;

	namelen = cell->name_len;
	if (size == 0)
	return namelen;
	if (namelen > size)
	return -ERANGE;
	memcpy(buffer, cell->name, namelen);
	return namelen;
	}

	static const struct xattr_handler afs_xattr_afs_cell_handler = {
	.name = "afs.cell",
	.get = afs_xattr_get_cell,
	};

	/*
	* Get the volume ID, vnode ID and vnode uniquifier of a file as a sequence of
	* hex numbers separated by colons.
	*/
	static int afs_xattr_get_fid(const struct xattr_handler *handler,
	struct dentry *dentry,
	struct inode inode, const char name,
	void *buffer, size_t size)
	{
	struct afs_vnode *vnode = AFS_FS_I(inode);
	char text[16 + 1 + 24 + 1 + 8 + 1];
	size_t len;

	/* The volume ID is 64-bit, the vnode ID is 96-bit and the
	* uniquifier is 32-bit.
	*/
	len = scnprintf(text, sizeof(text), "%llx:", vnode->fid.vid);
	if (vnode->fid.vnode_hi)
	len += scnprintf(text + len, sizeof(text) - len, "%x%016llx",
	vnode->fid.vnode_hi, vnode->fid.vnode);
	else
	len += scnprintf(text + len, sizeof(text) - len, "%llx",
	vnode->fid.vnode);
	len += scnprintf(text + len, sizeof(text) - len, ":%x",
	vnode->fid.unique);

	if (size == 0)
	return len;
	if (len > size)
	return -ERANGE;
	memcpy(buffer, text, len);
	return len;
	}

	static const struct xattr_handler afs_xattr_afs_fid_handler = {
	.name = "afs.fid",
	.get = afs_xattr_get_fid,
	};

	/*
	* Get the name of the volume on which a file resides.
	*/
	static int afs_xattr_get_volume(const struct xattr_handler *handler,
	struct dentry *dentry,
	struct inode inode, const char name,
	void *buffer, size_t size)
	{
	struct afs_vnode *vnode = AFS_FS_I(inode);
	const char *volname = vnode->volume->name;
	size_t namelen;

	namelen = strlen(volname);
	if (size == 0)
	return namelen;
	if (namelen > size)
	return -ERANGE;
	memcpy(buffer, volname, namelen);
	return namelen;
	}

	static const struct xattr_handler afs_xattr_afs_volume_handler = {
	.name = "afs.volume",
	.get = afs_xattr_get_volume,
	};

	const struct xattr_handler *afs_xattr_handlers[] = {
	&afs_xattr_afs_acl_handler,
	&afs_xattr_afs_cell_handler,
	&afs_xattr_afs_fid_handler,
	&afs_xattr_afs_volume_handler,
	&afs_xattr_yfs_handler, /* afs.yfs. prefix */
	NULL
	};