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alistair23-linux/fs/nfs/nfs3acl.c
Eric W. Biederman 5f3a4a28ec userns: Pass a userns parameter into posix_acl_to_xattr and posix_acl_from_xattr 
- Pass the user namespace the uid and gid values in the xattr are stored
   in into posix_acl_from_xattr.

 - Pass the user namespace kuid and kgid values should be converted into
   when storing uid and gid values in an xattr in posix_acl_to_xattr.

- Modify all callers of posix_acl_from_xattr and posix_acl_to_xattr to
  pass in &init_user_ns.

In the short term this change is not strictly needed but it makes the
code clearer.  In the longer term this change is necessary to be able to
mount filesystems outside of the initial user namespace that natively
store posix acls in the linux xattr format.

Cc: Theodore Tso <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Jan Kara <jack@suse.cz>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2012-09-18 01:01:35 -07:00

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#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"
#define NFSDBG_FACILITY NFSDBG_PROC
ssize_t nfs3_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
struct inode *inode = dentry->d_inode;
struct posix_acl *acl;
int pos=0, len=0;
# define output(s) do { \
if (pos + sizeof(s) <= size) { \
memcpy(buffer + pos, s, sizeof(s)); \
pos += sizeof(s); \
} \
len += sizeof(s); \
} while(0)
acl = nfs3_proc_getacl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
output("system.posix_acl_access");
posix_acl_release(acl);
}
if (S_ISDIR(inode->i_mode)) {
acl = nfs3_proc_getacl(inode, ACL_TYPE_DEFAULT);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
output("system.posix_acl_default");
posix_acl_release(acl);
}
}
# undef output
if (!buffer || len <= size)
return len;
return -ERANGE;
}
ssize_t nfs3_getxattr(struct dentry *dentry, const char *name,
void *buffer, size_t size)
{
struct inode *inode = dentry->d_inode;
struct posix_acl *acl;
int type, error = 0;
if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0)
type = ACL_TYPE_ACCESS;
else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0)
type = ACL_TYPE_DEFAULT;
else
return -EOPNOTSUPP;
acl = nfs3_proc_getacl(inode, type);
if (IS_ERR(acl))
return PTR_ERR(acl);
else if (acl) {
if (type == ACL_TYPE_ACCESS && acl->a_count == 0)
error = -ENODATA;
else
error = posix_acl_to_xattr(&init_user_ns, acl, buffer, size);
posix_acl_release(acl);
} else
error = -ENODATA;
return error;
}
int nfs3_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
struct inode *inode = dentry->d_inode;
struct posix_acl *acl;
int type, error;
if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0)
type = ACL_TYPE_ACCESS;
else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0)
type = ACL_TYPE_DEFAULT;
else
return -EOPNOTSUPP;
acl = posix_acl_from_xattr(&init_user_ns, value, size);
if (IS_ERR(acl))
return PTR_ERR(acl);
error = nfs3_proc_setacl(inode, type, acl);
posix_acl_release(acl);
return error;
}
int nfs3_removexattr(struct dentry *dentry, const char *name)
{
struct inode *inode = dentry->d_inode;
int type;
if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0)
type = ACL_TYPE_ACCESS;
else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0)
type = ACL_TYPE_DEFAULT;
else
return -EOPNOTSUPP;
return nfs3_proc_setacl(inode, type, NULL);
}
static void __nfs3_forget_cached_acls(struct nfs_inode *nfsi)
{
if (!IS_ERR(nfsi->acl_access)) {
posix_acl_release(nfsi->acl_access);
nfsi->acl_access = ERR_PTR(-EAGAIN);
}
if (!IS_ERR(nfsi->acl_default)) {
posix_acl_release(nfsi->acl_default);
nfsi->acl_default = ERR_PTR(-EAGAIN);
}
}
void nfs3_forget_cached_acls(struct inode *inode)
{
dprintk("NFS: nfs3_forget_cached_acls(%s/%ld)\n", inode->i_sb->s_id,
inode->i_ino);
spin_lock(&inode->i_lock);
__nfs3_forget_cached_acls(NFS_I(inode));
spin_unlock(&inode->i_lock);
}
static struct posix_acl *nfs3_get_cached_acl(struct inode *inode, int type)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct posix_acl *acl = ERR_PTR(-EINVAL);
spin_lock(&inode->i_lock);
switch(type) {
case ACL_TYPE_ACCESS:
acl = nfsi->acl_access;
break;
case ACL_TYPE_DEFAULT:
acl = nfsi->acl_default;
break;
default:
goto out;
}
if (IS_ERR(acl))
acl = ERR_PTR(-EAGAIN);
else
acl = posix_acl_dup(acl);
out:
spin_unlock(&inode->i_lock);
dprintk("NFS: nfs3_get_cached_acl(%s/%ld, %d) = %p\n", inode->i_sb->s_id,
inode->i_ino, type, acl);
return acl;
}
static void nfs3_cache_acls(struct inode *inode, struct posix_acl *acl,
struct posix_acl *dfacl)
{
struct nfs_inode *nfsi = NFS_I(inode);
dprintk("nfs3_cache_acls(%s/%ld, %p, %p)\n", inode->i_sb->s_id,
inode->i_ino, acl, dfacl);
spin_lock(&inode->i_lock);
__nfs3_forget_cached_acls(NFS_I(inode));
if (!IS_ERR(acl))
nfsi->acl_access = posix_acl_dup(acl);
if (!IS_ERR(dfacl))
nfsi->acl_default = posix_acl_dup(dfacl);
spin_unlock(&inode->i_lock);
}
struct posix_acl *nfs3_proc_getacl(struct inode *inode, int type)
{
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,
};
struct posix_acl *acl;
int status, count;
if (!nfs_server_capable(inode, NFS_CAP_ACLS))
return ERR_PTR(-EOPNOTSUPP);
status = nfs_revalidate_inode(server, inode);
if (status < 0)
return ERR_PTR(status);
acl = nfs3_get_cached_acl(inode, type);
if (acl != ERR_PTR(-EAGAIN))
return acl;
acl = NULL;
/*
* 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);
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;
case -ENOTSUPP:
status = -EOPNOTSUPP;
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) {
posix_acl_release(res.acl_access);
res.acl_access = NULL;
}
}
nfs3_cache_acls(inode,
(res.mask & NFS_ACL) ? res.acl_access : ERR_PTR(-EINVAL),
(res.mask & NFS_DFACL) ? res.acl_default : ERR_PTR(-EINVAL));
switch(type) {
case ACL_TYPE_ACCESS:
acl = res.acl_access;
res.acl_access = NULL;
break;
case ACL_TYPE_DEFAULT:
acl = res.acl_default;
res.acl_default = NULL;
}
getout:
posix_acl_release(res.acl_access);
posix_acl_release(res.acl_default);
nfs_free_fattr(res.fattr);
if (status != 0) {
posix_acl_release(acl);
acl = ERR_PTR(status);
}
return acl;
}
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;
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);
nfs3_cache_acls(inode, acl, dfacl);
break;
case -EPFNOSUPPORT:
case -EPROTONOSUPPORT:
dprintk("NFS_V3_ACL SETACL RPC not supported"
"(will not retry)\n");
server->caps &= ~NFS_CAP_ACLS;
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_setacl(struct inode *inode, int type, struct posix_acl *acl)
{
struct posix_acl *alloc = NULL, *dfacl = NULL;
int status;
if (S_ISDIR(inode->i_mode)) {
switch(type) {
case ACL_TYPE_ACCESS:
alloc = dfacl = nfs3_proc_getacl(inode,
ACL_TYPE_DEFAULT);
if (IS_ERR(alloc))
goto fail;
break;
case ACL_TYPE_DEFAULT:
dfacl = acl;
alloc = acl = nfs3_proc_getacl(inode,
ACL_TYPE_ACCESS);
if (IS_ERR(alloc))
goto fail;
break;
default:
return -EINVAL;
}
} else if (type != ACL_TYPE_ACCESS)
return -EINVAL;
if (acl == NULL) {
alloc = acl = posix_acl_from_mode(inode->i_mode, GFP_KERNEL);
if (IS_ERR(alloc))
goto fail;
}
status = nfs3_proc_setacls(inode, acl, dfacl);
posix_acl_release(alloc);
return status;
fail:
return PTR_ERR(alloc);
}
int nfs3_proc_set_default_acl(struct inode *dir, struct inode *inode,
umode_t mode)
{
struct posix_acl *dfacl, *acl;
int error = 0;
dfacl = nfs3_proc_getacl(dir, ACL_TYPE_DEFAULT);
if (IS_ERR(dfacl)) {
error = PTR_ERR(dfacl);
return (error == -EOPNOTSUPP) ? 0 : error;
}
if (!dfacl)
return 0;
acl = posix_acl_dup(dfacl);
error = posix_acl_create(&acl, GFP_KERNEL, &mode);
if (error < 0)
goto out_release_dfacl;
error = nfs3_proc_setacls(inode, acl, S_ISDIR(inode->i_mode) ?
dfacl : NULL);
posix_acl_release(acl);
out_release_dfacl:
posix_acl_release(dfacl);
return error;
}
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