linux/fs/xfs/xfs_xattr.c
Allison Henderson d29f781c32 xfs: Remove all strlen in all xfs_attr_* functions for attr names.
This helps to pre-simplify the extra handling of the null terminator in
delayed operations which use memcpy rather than strlen.  Later
when we introduce parent pointers, attribute names will become binary,
so strlen will not work at all.  Removing uses of strlen now will
help reduce complexities later

Signed-off-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-01-09 10:55:19 -08:00

245 lines
5.5 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2008 Christoph Hellwig.
* Portions Copyright (C) 2000-2008 Silicon Graphics, Inc.
*/
#include "xfs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_da_format.h"
#include "xfs_inode.h"
#include "xfs_attr.h"
#include "xfs_acl.h"
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
static int
xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
struct inode *inode, const char *name, void *value, size_t size)
{
int xflags = handler->flags;
struct xfs_inode *ip = XFS_I(inode);
int error, asize = size;
size_t namelen = strlen(name);
/* Convert Linux syscall to XFS internal ATTR flags */
if (!size) {
xflags |= ATTR_KERNOVAL;
value = NULL;
}
error = xfs_attr_get(ip, name, namelen, (unsigned char **)&value,
&asize, xflags);
if (error)
return error;
return asize;
}
void
xfs_forget_acl(
struct inode *inode,
const char *name,
int xflags)
{
/*
* Invalidate any cached ACLs if the user has bypassed the ACL
* interface. We don't validate the content whatsoever so it is caller
* responsibility to provide data in valid format and ensure i_mode is
* consistent.
*/
if (xflags & ATTR_ROOT) {
#ifdef CONFIG_XFS_POSIX_ACL
if (!strcmp(name, SGI_ACL_FILE))
forget_cached_acl(inode, ACL_TYPE_ACCESS);
else if (!strcmp(name, SGI_ACL_DEFAULT))
forget_cached_acl(inode, ACL_TYPE_DEFAULT);
#endif
}
}
static int
xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
struct inode *inode, const char *name, const void *value,
size_t size, int flags)
{
int xflags = handler->flags;
struct xfs_inode *ip = XFS_I(inode);
int error;
size_t namelen = strlen(name);
/* Convert Linux syscall to XFS internal ATTR flags */
if (flags & XATTR_CREATE)
xflags |= ATTR_CREATE;
if (flags & XATTR_REPLACE)
xflags |= ATTR_REPLACE;
if (value)
error = xfs_attr_set(ip, name, namelen, (void *)value, size,
xflags);
else
error = xfs_attr_remove(ip, name, namelen, xflags);
if (!error)
xfs_forget_acl(inode, name, xflags);
return error;
}
static const struct xattr_handler xfs_xattr_user_handler = {
.prefix = XATTR_USER_PREFIX,
.flags = 0, /* no flags implies user namespace */
.get = xfs_xattr_get,
.set = xfs_xattr_set,
};
static const struct xattr_handler xfs_xattr_trusted_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.flags = ATTR_ROOT,
.get = xfs_xattr_get,
.set = xfs_xattr_set,
};
static const struct xattr_handler xfs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.flags = ATTR_SECURE,
.get = xfs_xattr_get,
.set = xfs_xattr_set,
};
const struct xattr_handler *xfs_xattr_handlers[] = {
&xfs_xattr_user_handler,
&xfs_xattr_trusted_handler,
&xfs_xattr_security_handler,
#ifdef CONFIG_XFS_POSIX_ACL
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
#endif
NULL
};
static void
__xfs_xattr_put_listent(
struct xfs_attr_list_context *context,
char *prefix,
int prefix_len,
unsigned char *name,
int namelen)
{
char *offset;
int arraytop;
if (context->count < 0 || context->seen_enough)
return;
if (!context->alist)
goto compute_size;
arraytop = context->count + prefix_len + namelen + 1;
if (arraytop > context->firstu) {
context->count = -1; /* insufficient space */
context->seen_enough = 1;
return;
}
offset = (char *)context->alist + context->count;
strncpy(offset, prefix, prefix_len);
offset += prefix_len;
strncpy(offset, (char *)name, namelen); /* real name */
offset += namelen;
*offset = '\0';
compute_size:
context->count += prefix_len + namelen + 1;
return;
}
static void
xfs_xattr_put_listent(
struct xfs_attr_list_context *context,
int flags,
unsigned char *name,
int namelen,
int valuelen)
{
char *prefix;
int prefix_len;
ASSERT(context->count >= 0);
if (flags & XFS_ATTR_ROOT) {
#ifdef CONFIG_XFS_POSIX_ACL
if (namelen == SGI_ACL_FILE_SIZE &&
strncmp(name, SGI_ACL_FILE,
SGI_ACL_FILE_SIZE) == 0) {
__xfs_xattr_put_listent(
context, XATTR_SYSTEM_PREFIX,
XATTR_SYSTEM_PREFIX_LEN,
XATTR_POSIX_ACL_ACCESS,
strlen(XATTR_POSIX_ACL_ACCESS));
} else if (namelen == SGI_ACL_DEFAULT_SIZE &&
strncmp(name, SGI_ACL_DEFAULT,
SGI_ACL_DEFAULT_SIZE) == 0) {
__xfs_xattr_put_listent(
context, XATTR_SYSTEM_PREFIX,
XATTR_SYSTEM_PREFIX_LEN,
XATTR_POSIX_ACL_DEFAULT,
strlen(XATTR_POSIX_ACL_DEFAULT));
}
#endif
/*
* Only show root namespace entries if we are actually allowed to
* see them.
*/
if (!capable(CAP_SYS_ADMIN))
return;
prefix = XATTR_TRUSTED_PREFIX;
prefix_len = XATTR_TRUSTED_PREFIX_LEN;
} else if (flags & XFS_ATTR_SECURE) {
prefix = XATTR_SECURITY_PREFIX;
prefix_len = XATTR_SECURITY_PREFIX_LEN;
} else {
prefix = XATTR_USER_PREFIX;
prefix_len = XATTR_USER_PREFIX_LEN;
}
__xfs_xattr_put_listent(context, prefix, prefix_len, name,
namelen);
return;
}
ssize_t
xfs_vn_listxattr(
struct dentry *dentry,
char *data,
size_t size)
{
struct xfs_attr_list_context context;
struct attrlist_cursor_kern cursor = { 0 };
struct inode *inode = d_inode(dentry);
int error;
/*
* First read the regular on-disk attributes.
*/
memset(&context, 0, sizeof(context));
context.dp = XFS_I(inode);
context.cursor = &cursor;
context.resynch = 1;
context.alist = size ? data : NULL;
context.bufsize = size;
context.firstu = context.bufsize;
context.put_listent = xfs_xattr_put_listent;
error = xfs_attr_list_int(&context);
if (error)
return error;
if (context.count < 0)
return -ERANGE;
return context.count;
}