// 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 the ACL isn't being read yet, set our sentinel. */
cmpxchg(p, ACL_NOT_CACHED, sentinel);
}
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 mnt_idmap *idmap, 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;
}
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;
}
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