fs/nfs/nfs3acl.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 #include <linux/fs.h>
 #include <linux/gfp.h>
 #include <linux/nfs.h>
 #include <linux/nfs3.h>
 #include <linux/nfs_fs.h>
 #include <linux/posix_acl_xattr.h>
 #include <linux/nfsacl.h>

 #include "internal.h"
 #include "nfs3_fs.h"

 #define NFSDBG_FACILITY	NFSDBG_PROC

 /*
  * nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for
  * caching get_acl results in a race-free way.  See fs/posix_acl.c:get_acl()
  * for explanations.
  */
 static void nfs3_prepare_get_acl(struct posix_acl **p)
 {
 	struct posix_acl *sentinel = uncached_acl_sentinel(current);

 	if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) {
 		/* Not the first reader or sentinel already in place. */
 	}
 }

 static void nfs3_complete_get_acl(struct posix_acl **p, struct posix_acl *acl)
 {
 	struct posix_acl *sentinel = uncached_acl_sentinel(current);

 	/* Only cache the ACL if our sentinel is still in place. */
 	posix_acl_dup(acl);
 	if (cmpxchg(p, sentinel, acl) != sentinel)
 		posix_acl_release(acl);
 }

 static void nfs3_abort_get_acl(struct posix_acl **p)
 {
 	struct posix_acl *sentinel = uncached_acl_sentinel(current);

 	/* Remove our sentinel upon failure. */
 	cmpxchg(p, sentinel, ACL_NOT_CACHED);
 }

 struct posix_acl *nfs3_get_acl(struct inode *inode, int type, bool rcu)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
 	struct page *pages[NFSACL_MAXPAGES] = { };
 	struct nfs3_getaclargs args = {
 		.fh = NFS_FH(inode),
 		/* The xdr layer may allocate pages here. */
 		.pages = pages,
 	};
 	struct nfs3_getaclres res = {
 		NULL,
 	};
 	struct rpc_message msg = {
 		.rpc_argp	= &args,
 		.rpc_resp	= &res,
 	};
 	int status, count;

 	if (rcu)
 		return ERR_PTR(-ECHILD);

 	if (!nfs_server_capable(inode, NFS_CAP_ACLS))
 		return ERR_PTR(-EOPNOTSUPP);

 	status = nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE);
 	if (status < 0)
 		return ERR_PTR(status);

 	/*
 	 * Only get the access acl when explicitly requested: We don't
 	 * need it for access decisions, and only some applications use
 	 * it. Applications which request the access acl first are not
 	 * penalized from this optimization.
 	 */
 	if (type == ACL_TYPE_ACCESS)
 		args.mask |= NFS_ACLCNT|NFS_ACL;
 	if (S_ISDIR(inode->i_mode))
 		args.mask |= NFS_DFACLCNT|NFS_DFACL;
 	if (args.mask == 0)
 		return NULL;

 	dprintk("NFS call getacl\n");
 	msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL];
 	res.fattr = nfs_alloc_fattr();
 	if (res.fattr == NULL)
 		return ERR_PTR(-ENOMEM);

 	if (args.mask & NFS_ACL)
 		nfs3_prepare_get_acl(&inode->i_acl);
 	if (args.mask & NFS_DFACL)
 		nfs3_prepare_get_acl(&inode->i_default_acl);

 	status = rpc_call_sync(server->client_acl, &msg, 0);
 	dprintk("NFS reply getacl: %d\n", status);

 	/* pages may have been allocated at the xdr layer. */
 	for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
 		__free_page(args.pages[count]);

 	switch (status) {
 		case 0:
 			status = nfs_refresh_inode(inode, res.fattr);
 			break;
 		case -EPFNOSUPPORT:
 		case -EPROTONOSUPPORT:
 			dprintk("NFS_V3_ACL extension not supported; disabling\n");
 			server->caps &= ~NFS_CAP_ACLS;
 			fallthrough;
 		case -ENOTSUPP:
 			status = -EOPNOTSUPP;
 			goto getout;
 		default:
 			goto getout;
 	}
 	if ((args.mask & res.mask) != args.mask) {
 		status = -EIO;
 		goto getout;
 	}

 	if (res.acl_access != NULL) {
 		if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) ||
 		    res.acl_access->a_count == 0) {
 			posix_acl_release(res.acl_access);
 			res.acl_access = NULL;
 		}
 	}

 	if (res.mask & NFS_ACL)
 		nfs3_complete_get_acl(&inode->i_acl, res.acl_access);
 	else
 		forget_cached_acl(inode, ACL_TYPE_ACCESS);

 	if (res.mask & NFS_DFACL)
 		nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default);
 	else
 		forget_cached_acl(inode, ACL_TYPE_DEFAULT);

 	nfs_free_fattr(res.fattr);
 	if (type == ACL_TYPE_ACCESS) {
 		posix_acl_release(res.acl_default);
 		return res.acl_access;
 	} else {
 		posix_acl_release(res.acl_access);
 		return res.acl_default;
 	}

 getout:
 	nfs3_abort_get_acl(&inode->i_acl);
 	nfs3_abort_get_acl(&inode->i_default_acl);
 	posix_acl_release(res.acl_access);
 	posix_acl_release(res.acl_default);
 	nfs_free_fattr(res.fattr);
 	return ERR_PTR(status);
 }

 static int __nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
 		struct posix_acl *dfacl)
 {
 	struct nfs_server *server = NFS_SERVER(inode);
 	struct nfs_fattr *fattr;
 	struct page *pages[NFSACL_MAXPAGES];
 	struct nfs3_setaclargs args = {
 		.inode = inode,
 		.mask = NFS_ACL,
 		.acl_access = acl,
 		.pages = pages,
 	};
 	struct rpc_message msg = {
 		.rpc_argp	= &args,
 		.rpc_resp	= &fattr,
 	};
 	int status = 0;

 	if (acl == NULL && (!S_ISDIR(inode->i_mode) || dfacl == NULL))
 		goto out;

 	status = -EOPNOTSUPP;
 	if (!nfs_server_capable(inode, NFS_CAP_ACLS))
 		goto out;

 	/* We are doing this here because XDR marshalling does not
 	 * return any results, it BUGs. */
 	status = -ENOSPC;
 	if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES)
 		goto out;
 	if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES)
 		goto out;
 	if (S_ISDIR(inode->i_mode)) {
 		args.mask |= NFS_DFACL;
 		args.acl_default = dfacl;
 		args.len = nfsacl_size(acl, dfacl);
 	} else
 		args.len = nfsacl_size(acl, NULL);

 	if (args.len > NFS_ACL_INLINE_BUFSIZE) {
 		unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT);

 		status = -ENOMEM;
 		do {
 			args.pages[args.npages] = alloc_page(GFP_KERNEL);
 			if (args.pages[args.npages] == NULL)
 				goto out_freepages;
 			args.npages++;
 		} while (args.npages < npages);
 	}

 	dprintk("NFS call setacl\n");
 	status = -ENOMEM;
 	fattr = nfs_alloc_fattr();
 	if (fattr == NULL)
 		goto out_freepages;

 	msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL];
 	msg.rpc_resp = fattr;
 	status = rpc_call_sync(server->client_acl, &msg, 0);
 	nfs_access_zap_cache(inode);
 	nfs_zap_acl_cache(inode);
 	dprintk("NFS reply setacl: %d\n", status);

 	switch (status) {
 		case 0:
 			status = nfs_refresh_inode(inode, fattr);
 			break;
 		case -EPFNOSUPPORT:
 		case -EPROTONOSUPPORT:
 			dprintk("NFS_V3_ACL SETACL RPC not supported"
 					"(will not retry)\n");
 			server->caps &= ~NFS_CAP_ACLS;
 			fallthrough;
 		case -ENOTSUPP:
 			status = -EOPNOTSUPP;
 	}
 	nfs_free_fattr(fattr);
 out_freepages:
 	while (args.npages != 0) {
 		args.npages--;
 		__free_page(args.pages[args.npages]);
 	}
 out:
 	return status;
 }

 int nfs3_proc_setacls(struct inode *inode, struct posix_acl *acl,
 		struct posix_acl *dfacl)
 {
 	int ret;
 	ret = __nfs3_proc_setacls(inode, acl, dfacl);
 	return (ret == -EOPNOTSUPP) ? 0 : ret;

 }

 int nfs3_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry,
 		 struct posix_acl *acl, int type)
 {
 	struct posix_acl *orig = acl, *dfacl = NULL, *alloc;
 	struct inode *inode = d_inode(dentry);
 	int status;

 	if (S_ISDIR(inode->i_mode)) {
 		switch(type) {
 		case ACL_TYPE_ACCESS:
 			alloc = get_inode_acl(inode, ACL_TYPE_DEFAULT);
 			if (IS_ERR(alloc))
 				goto fail;
 			dfacl = alloc;
 			break;

 		case ACL_TYPE_DEFAULT:
 			alloc = get_inode_acl(inode, ACL_TYPE_ACCESS);
 			if (IS_ERR(alloc))
 				goto fail;
 			dfacl = acl;
 			acl = alloc;
 			break;
 		}
 	}

 	if (acl == NULL) {
 		alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
 		if (IS_ERR(alloc))
 			goto fail;
 		acl = alloc;
 	}
 	status = __nfs3_proc_setacls(inode, acl, dfacl);
 out:
 	if (acl != orig)
 		posix_acl_release(acl);
 	if (dfacl != orig)
 		posix_acl_release(dfacl);
 	return status;

 fail:
 	status = PTR_ERR(alloc);
 	goto out;
 }

 const struct xattr_handler *nfs3_xattr_handlers[] = {
 	&posix_acl_access_xattr_handler,
 	&posix_acl_default_xattr_handler,
 	NULL,
 };

 static int
 nfs3_list_one_acl(struct inode *inode, int type, const char *name, void *data,
 		size_t size, ssize_t *result)
 {
 	struct posix_acl *acl;
 	char *p = data + *result;

 	acl = get_inode_acl(inode, type);
 	if (IS_ERR_OR_NULL(acl))
 		return 0;

 	posix_acl_release(acl);

 	*result += strlen(name);
 	*result += 1;
 	if (!size)
 		return 0;
 	if (*result > size)
 		return -ERANGE;

 	strcpy(p, name);
 	return 0;
 }

 ssize_t
 nfs3_listxattr(struct dentry *dentry, char *data, size_t size)
 {
 	struct inode *inode = d_inode(dentry);
 	ssize_t result = 0;
 	int error;

 	error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS,
 			XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result);
 	if (error)
 		return error;

 	error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT,
 			XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result);
 	if (error)
 		return error;
 	return result;
 }
	// SPDX-License-Identifier: GPL-2.0
	#include <linux/fs.h>
	#include <linux/gfp.h>
	#include <linux/nfs.h>
	#include <linux/nfs3.h>
	#include <linux/nfs_fs.h>
	#include <linux/posix_acl_xattr.h>
	#include <linux/nfsacl.h>

	#include "internal.h"
	#include "nfs3_fs.h"

	#define NFSDBG_FACILITY NFSDBG_PROC

	/*
	* nfs3_prepare_get_acl, nfs3_complete_get_acl, nfs3_abort_get_acl: Helpers for
	* caching get_acl results in a race-free way. See fs/posix_acl.c:get_acl()
	* for explanations.
	*/
	static void nfs3_prepare_get_acl(struct posix_acl **p)
	{
	struct posix_acl *sentinel = uncached_acl_sentinel(current);

	if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) {
	/* Not the first reader or sentinel already in place. */
	}
	}

	static void nfs3_complete_get_acl(struct posix_acl *p, struct posix_acl acl)
	{
	struct posix_acl *sentinel = uncached_acl_sentinel(current);

	/* Only cache the ACL if our sentinel is still in place. */
	posix_acl_dup(acl);
	if (cmpxchg(p, sentinel, acl) != sentinel)
	posix_acl_release(acl);
	}

	static void nfs3_abort_get_acl(struct posix_acl **p)
	{
	struct posix_acl *sentinel = uncached_acl_sentinel(current);

	/* Remove our sentinel upon failure. */
	cmpxchg(p, sentinel, ACL_NOT_CACHED);
	}

	struct posix_acl nfs3_get_acl(struct inode inode, int type, bool rcu)
	{
	struct nfs_server *server = NFS_SERVER(inode);
	struct page *pages[NFSACL_MAXPAGES] = { };
	struct nfs3_getaclargs args = {
	.fh = NFS_FH(inode),
	/* The xdr layer may allocate pages here. */
	.pages = pages,
	};
	struct nfs3_getaclres res = {
	NULL,
	};
	struct rpc_message msg = {
	.rpc_argp = &args,
	.rpc_resp = &res,
	};
	int status, count;

	if (rcu)
	return ERR_PTR(-ECHILD);

	if (!nfs_server_capable(inode, NFS_CAP_ACLS))
	return ERR_PTR(-EOPNOTSUPP);

	status = nfs_revalidate_inode(inode, NFS_INO_INVALID_CHANGE);
	if (status < 0)
	return ERR_PTR(status);

	/*
	* Only get the access acl when explicitly requested: We don't
	* need it for access decisions, and only some applications use
	* it. Applications which request the access acl first are not
	* penalized from this optimization.
	*/
	if (type == ACL_TYPE_ACCESS)
	args.mask \|= NFS_ACLCNT\|NFS_ACL;
	if (S_ISDIR(inode->i_mode))
	args.mask \|= NFS_DFACLCNT\|NFS_DFACL;
	if (args.mask == 0)
	return NULL;

	dprintk("NFS call getacl\n");
	msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_GETACL];
	res.fattr = nfs_alloc_fattr();
	if (res.fattr == NULL)
	return ERR_PTR(-ENOMEM);

	if (args.mask & NFS_ACL)
	nfs3_prepare_get_acl(&inode->i_acl);
	if (args.mask & NFS_DFACL)
	nfs3_prepare_get_acl(&inode->i_default_acl);

	status = rpc_call_sync(server->client_acl, &msg, 0);
	dprintk("NFS reply getacl: %d\n", status);

	/* pages may have been allocated at the xdr layer. */
	for (count = 0; count < NFSACL_MAXPAGES && args.pages[count]; count++)
	__free_page(args.pages[count]);

	switch (status) {
	case 0:
	status = nfs_refresh_inode(inode, res.fattr);
	break;
	case -EPFNOSUPPORT:
	case -EPROTONOSUPPORT:
	dprintk("NFS_V3_ACL extension not supported; disabling\n");
	server->caps &= ~NFS_CAP_ACLS;
	fallthrough;
	case -ENOTSUPP:
	status = -EOPNOTSUPP;
	goto getout;
	default:
	goto getout;
	}
	if ((args.mask & res.mask) != args.mask) {
	status = -EIO;
	goto getout;
	}

	if (res.acl_access != NULL) {
	if ((posix_acl_equiv_mode(res.acl_access, NULL) == 0) \|\|
	res.acl_access->a_count == 0) {
	posix_acl_release(res.acl_access);
	res.acl_access = NULL;
	}
	}

	if (res.mask & NFS_ACL)
	nfs3_complete_get_acl(&inode->i_acl, res.acl_access);
	else
	forget_cached_acl(inode, ACL_TYPE_ACCESS);

	if (res.mask & NFS_DFACL)
	nfs3_complete_get_acl(&inode->i_default_acl, res.acl_default);
	else
	forget_cached_acl(inode, ACL_TYPE_DEFAULT);

	nfs_free_fattr(res.fattr);
	if (type == ACL_TYPE_ACCESS) {
	posix_acl_release(res.acl_default);
	return res.acl_access;
	} else {
	posix_acl_release(res.acl_access);
	return res.acl_default;
	}

	getout:
	nfs3_abort_get_acl(&inode->i_acl);
	nfs3_abort_get_acl(&inode->i_default_acl);
	posix_acl_release(res.acl_access);
	posix_acl_release(res.acl_default);
	nfs_free_fattr(res.fattr);
	return ERR_PTR(status);
	}

	static int __nfs3_proc_setacls(struct inode inode, struct posix_acl acl,
	struct posix_acl *dfacl)
	{
	struct nfs_server *server = NFS_SERVER(inode);
	struct nfs_fattr *fattr;
	struct page *pages[NFSACL_MAXPAGES];
	struct nfs3_setaclargs args = {
	.inode = inode,
	.mask = NFS_ACL,
	.acl_access = acl,
	.pages = pages,
	};
	struct rpc_message msg = {
	.rpc_argp = &args,
	.rpc_resp = &fattr,
	};
	int status = 0;

	if (acl == NULL && (!S_ISDIR(inode->i_mode) \|\| dfacl == NULL))
	goto out;

	status = -EOPNOTSUPP;
	if (!nfs_server_capable(inode, NFS_CAP_ACLS))
	goto out;

	/* We are doing this here because XDR marshalling does not
	* return any results, it BUGs. */
	status = -ENOSPC;
	if (acl != NULL && acl->a_count > NFS_ACL_MAX_ENTRIES)
	goto out;
	if (dfacl != NULL && dfacl->a_count > NFS_ACL_MAX_ENTRIES)
	goto out;
	if (S_ISDIR(inode->i_mode)) {
	args.mask \|= NFS_DFACL;
	args.acl_default = dfacl;
	args.len = nfsacl_size(acl, dfacl);
	} else
	args.len = nfsacl_size(acl, NULL);

	if (args.len > NFS_ACL_INLINE_BUFSIZE) {
	unsigned int npages = 1 + ((args.len - 1) >> PAGE_SHIFT);

	status = -ENOMEM;
	do {
	args.pages[args.npages] = alloc_page(GFP_KERNEL);
	if (args.pages[args.npages] == NULL)
	goto out_freepages;
	args.npages++;
	} while (args.npages < npages);
	}

	dprintk("NFS call setacl\n");
	status = -ENOMEM;
	fattr = nfs_alloc_fattr();
	if (fattr == NULL)
	goto out_freepages;

	msg.rpc_proc = &server->client_acl->cl_procinfo[ACLPROC3_SETACL];
	msg.rpc_resp = fattr;
	status = rpc_call_sync(server->client_acl, &msg, 0);
	nfs_access_zap_cache(inode);
	nfs_zap_acl_cache(inode);
	dprintk("NFS reply setacl: %d\n", status);

	switch (status) {
	case 0:
	status = nfs_refresh_inode(inode, fattr);
	break;
	case -EPFNOSUPPORT:
	case -EPROTONOSUPPORT:
	dprintk("NFS_V3_ACL SETACL RPC not supported"
	"(will not retry)\n");
	server->caps &= ~NFS_CAP_ACLS;
	fallthrough;
	case -ENOTSUPP:
	status = -EOPNOTSUPP;
	}
	nfs_free_fattr(fattr);
	out_freepages:
	while (args.npages != 0) {
	args.npages--;
	__free_page(args.pages[args.npages]);
	}
	out:
	return status;
	}

	int nfs3_proc_setacls(struct inode inode, struct posix_acl acl,
	struct posix_acl *dfacl)
	{
	int ret;
	ret = __nfs3_proc_setacls(inode, acl, dfacl);
	return (ret == -EOPNOTSUPP) ? 0 : ret;

	}

	int nfs3_set_acl(struct user_namespace mnt_userns, struct dentry dentry,
	struct posix_acl *acl, int type)
	{
	struct posix_acl orig = acl, dfacl = NULL, *alloc;
	struct inode *inode = d_inode(dentry);
	int status;

	if (S_ISDIR(inode->i_mode)) {
	switch(type) {
	case ACL_TYPE_ACCESS:
	alloc = get_inode_acl(inode, ACL_TYPE_DEFAULT);
	if (IS_ERR(alloc))
	goto fail;
	dfacl = alloc;
	break;

	case ACL_TYPE_DEFAULT:
	alloc = get_inode_acl(inode, ACL_TYPE_ACCESS);
	if (IS_ERR(alloc))
	goto fail;
	dfacl = acl;
	acl = alloc;
	break;
	}
	}

	if (acl == NULL) {
	alloc = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
	if (IS_ERR(alloc))
	goto fail;
	acl = alloc;
	}
	status = __nfs3_proc_setacls(inode, acl, dfacl);
	out:
	if (acl != orig)
	posix_acl_release(acl);
	if (dfacl != orig)
	posix_acl_release(dfacl);
	return status;

	fail:
	status = PTR_ERR(alloc);
	goto out;
	}

	const struct xattr_handler *nfs3_xattr_handlers[] = {
	&posix_acl_access_xattr_handler,
	&posix_acl_default_xattr_handler,
	NULL,
	};

	static int
	nfs3_list_one_acl(struct inode inode, int type, const char name, void *data,
	size_t size, ssize_t *result)
	{
	struct posix_acl *acl;
	char p = data + result;

	acl = get_inode_acl(inode, type);
	if (IS_ERR_OR_NULL(acl))
	return 0;

	posix_acl_release(acl);

	*result += strlen(name);
	*result += 1;
	if (!size)
	return 0;
	if (*result > size)
	return -ERANGE;

	strcpy(p, name);
	return 0;
	}

	ssize_t
	nfs3_listxattr(struct dentry dentry, char data, size_t size)
	{
	struct inode *inode = d_inode(dentry);
	ssize_t result = 0;
	int error;

	error = nfs3_list_one_acl(inode, ACL_TYPE_ACCESS,
	XATTR_NAME_POSIX_ACL_ACCESS, data, size, &result);
	if (error)
	return error;

	error = nfs3_list_one_acl(inode, ACL_TYPE_DEFAULT,
	XATTR_NAME_POSIX_ACL_DEFAULT, data, size, &result);
	if (error)
	return error;
	return result;
	}