1 files changed, 349 insertions, 0 deletions
diff --git a/fs/nfs/nfs3acl.c b/fs/nfs/nfs3acl.c
new file mode 100644
index 000000000..93de0b586
--- /dev/null
+++ b/fs/nfs/nfs3acl.c
@@ -0,0 +1,349 @@
+// 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 inode *inode,
+		 struct posix_acl *acl, int type)
+{
+	struct posix_acl *orig = acl, *dfacl = NULL, *alloc;
+	int status;
+
+	if (S_ISDIR(inode->i_mode)) {
+		switch(type) {
+		case ACL_TYPE_ACCESS:
+			alloc = get_acl(inode, ACL_TYPE_DEFAULT);
+			if (IS_ERR(alloc))
+				goto fail;
+			dfacl = alloc;
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			alloc = get_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_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;
+}