korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-23 02:54:32 +08:00
Code Issues Packages Projects Releases Wiki Activity
65e67f5165
linux/fs/jfs/xattr.c
Satyam Sharma 3bd858ab1c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 
Introduce is_owner_or_cap() macro in fs.h, and convert over relevant
users to it. This is done because we want to avoid bugs in the future
where we check for only effective fsuid of the current task against a
file's owning uid, without simultaneously checking for CAP_FOWNER as
well, thus violating its semantics.
[ XFS uses special macros and structures, and in general looked ...
untouchable, so we leave it alone -- but it has been looked over. ]

The (current->fsuid != inode->i_uid) check in generic_permission() and
exec_permission_lite() is left alone, because those operations are
covered by CAP_DAC_OVERRIDE and CAP_DAC_READ_SEARCH. Similarly operations
falling under the purview of CAP_CHOWN and CAP_LEASE are also left alone.

Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in>
Cc: Al Viro <viro@ftp.linux.org.uk>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 12:00:03 -07:00

1142 lines
28 KiB
C
Raw Blame History

/*
* Copyright (C) International Business Machines Corp., 2000-2004
* Copyright (C) Christoph Hellwig, 2002
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/capability.h>
#include <linux/fs.h>
#include <linux/xattr.h>
#include <linux/posix_acl_xattr.h>
#include <linux/quotaops.h>
#include <linux/security.h>
#include "jfs_incore.h"
#include "jfs_superblock.h"
#include "jfs_dmap.h"
#include "jfs_debug.h"
#include "jfs_dinode.h"
#include "jfs_extent.h"
#include "jfs_metapage.h"
#include "jfs_xattr.h"
#include "jfs_acl.h"
/*
* jfs_xattr.c: extended attribute service
*
* Overall design --
*
* Format:
*
* Extended attribute lists (jfs_ea_list) consist of an overall size (32 bit
* value) and a variable (0 or more) number of extended attribute
* entries. Each extended attribute entry (jfs_ea) is a <name,value> double
* where <name> is constructed from a null-terminated ascii string
* (1 ... 255 bytes in the name) and <value> is arbitrary 8 bit data
* (1 ... 65535 bytes). The in-memory format is
*
* 0 1 2 4 4 + namelen + 1
* +-------+--------+--------+----------------+-------------------+
* | Flags | Name | Value | Name String \0 | Data . . . . |
* | | Length | Length | | |
* +-------+--------+--------+----------------+-------------------+
*
* A jfs_ea_list then is structured as
*
* 0 4 4 + EA_SIZE(ea1)
* +------------+-------------------+--------------------+-----
* | Overall EA | First FEA Element | Second FEA Element | .....
* | List Size | | |
* +------------+-------------------+--------------------+-----
*
* On-disk:
*
* FEALISTs are stored on disk using blocks allocated by dbAlloc() and
* written directly. An EA list may be in-lined in the inode if there is
* sufficient room available.
*/
struct ea_buffer {
int flag; /* Indicates what storage xattr points to */
int max_size; /* largest xattr that fits in current buffer */
dxd_t new_ea; /* dxd to replace ea when modifying xattr */
struct metapage *mp; /* metapage containing ea list */
struct jfs_ea_list *xattr; /* buffer containing ea list */
};
/*
* ea_buffer.flag values
*/
#define EA_INLINE 0x0001
#define EA_EXTENT 0x0002
#define EA_NEW 0x0004
#define EA_MALLOC 0x0008
/*
* These three routines are used to recognize on-disk extended attributes
* that are in a recognized namespace. If the attribute is not recognized,
* "os2." is prepended to the name
*/
static inline int is_os2_xattr(struct jfs_ea *ea)
{
/*
* Check for "system."
*/
if ((ea->namelen >= XATTR_SYSTEM_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
return false;
/*
* Check for "user."
*/
if ((ea->namelen >= XATTR_USER_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
return false;
/*
* Check for "security."
*/
if ((ea->namelen >= XATTR_SECURITY_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_SECURITY_PREFIX,
XATTR_SECURITY_PREFIX_LEN))
return false;
/*
* Check for "trusted."
*/
if ((ea->namelen >= XATTR_TRUSTED_PREFIX_LEN) &&
!strncmp(ea->name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
return false;
/*
* Add any other valid namespace prefixes here
*/
/*
* We assume it's OS/2's flat namespace
*/
return true;
}
static inline int name_size(struct jfs_ea *ea)
{
if (is_os2_xattr(ea))
return ea->namelen + XATTR_OS2_PREFIX_LEN;
else
return ea->namelen;
}
static inline int copy_name(char *buffer, struct jfs_ea *ea)
{
int len = ea->namelen;
if (is_os2_xattr(ea)) {
memcpy(buffer, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN);
buffer += XATTR_OS2_PREFIX_LEN;
len += XATTR_OS2_PREFIX_LEN;
}
memcpy(buffer, ea->name, ea->namelen);
buffer[ea->namelen] = 0;
return len;
}
/* Forward references */
static void ea_release(struct inode *inode, struct ea_buffer *ea_buf);
/*
* NAME: ea_write_inline
*
* FUNCTION: Attempt to write an EA inline if area is available
*
* PRE CONDITIONS:
* Already verified that the specified EA is small enough to fit inline
*
* PARAMETERS:
* ip - Inode pointer
* ealist - EA list pointer
* size - size of ealist in bytes
* ea - dxd_t structure to be filled in with necessary EA information
* if we successfully copy the EA inline
*
* NOTES:
* Checks if the inode's inline area is available. If so, copies EA inline
* and sets <ea> fields appropriately. Otherwise, returns failure, EA will
* have to be put into an extent.
*
* RETURNS: 0 for successful copy to inline area; -1 if area not available
*/
static int ea_write_inline(struct inode *ip, struct jfs_ea_list *ealist,
int size, dxd_t * ea)
{
struct jfs_inode_info *ji = JFS_IP(ip);
/*
* Make sure we have an EA -- the NULL EA list is valid, but you
* can't copy it!
*/
if (ealist && size > sizeof (struct jfs_ea_list)) {
assert(size <= sizeof (ji->i_inline_ea));
/*
* See if the space is available or if it is already being
* used for an inline EA.
*/
if (!(ji->mode2 & INLINEEA) && !(ji->ea.flag & DXD_INLINE))
return -EPERM;
DXDsize(ea, size);
DXDlength(ea, 0);
DXDaddress(ea, 0);
memcpy(ji->i_inline_ea, ealist, size);
ea->flag = DXD_INLINE;
ji->mode2 &= ~INLINEEA;
} else {
ea->flag = 0;
DXDsize(ea, 0);
DXDlength(ea, 0);
DXDaddress(ea, 0);
/* Free up INLINE area */
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
}
return 0;
}
/*
* NAME: ea_write
*
* FUNCTION: Write an EA for an inode
*
* PRE CONDITIONS: EA has been verified
*
* PARAMETERS:
* ip - Inode pointer
* ealist - EA list pointer
* size - size of ealist in bytes
* ea - dxd_t structure to be filled in appropriately with where the
* EA was copied
*
* NOTES: Will write EA inline if able to, otherwise allocates blocks for an
* extent and synchronously writes it to those blocks.
*
* RETURNS: 0 for success; Anything else indicates failure
*/
static int ea_write(struct inode *ip, struct jfs_ea_list *ealist, int size,
dxd_t * ea)
{
struct super_block *sb = ip->i_sb;
struct jfs_inode_info *ji = JFS_IP(ip);
struct jfs_sb_info *sbi = JFS_SBI(sb);
int nblocks;
s64 blkno;
int rc = 0, i;
char *cp;
s32 nbytes, nb;
s32 bytes_to_write;
struct metapage *mp;
/*
* Quick check to see if this is an in-linable EA. Short EAs
* and empty EAs are all in-linable, provided the space exists.
*/
if (!ealist || size <= sizeof (ji->i_inline_ea)) {
if (!ea_write_inline(ip, ealist, size, ea))
return 0;
}
/* figure out how many blocks we need */
nblocks = (size + (sb->s_blocksize - 1)) >> sb->s_blocksize_bits;
/* Allocate new blocks to quota. */
if (DQUOT_ALLOC_BLOCK(ip, nblocks)) {
return -EDQUOT;
}
rc = dbAlloc(ip, INOHINT(ip), nblocks, &blkno);
if (rc) {
/*Rollback quota allocation. */
DQUOT_FREE_BLOCK(ip, nblocks);
return rc;
}
/*
* Now have nblocks worth of storage to stuff into the FEALIST.
* loop over the FEALIST copying data into the buffer one page at
* a time.
*/
cp = (char *) ealist;
nbytes = size;
for (i = 0; i < nblocks; i += sbi->nbperpage) {
/*
* Determine how many bytes for this request, and round up to
* the nearest aggregate block size
*/
nb = min(PSIZE, nbytes);
bytes_to_write =
((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
<< sb->s_blocksize_bits;
if (!(mp = get_metapage(ip, blkno + i, bytes_to_write, 1))) {
rc = -EIO;
goto failed;
}
memcpy(mp->data, cp, nb);
/*
* We really need a way to propagate errors for
* forced writes like this one. --hch
*
* (__write_metapage => release_metapage => flush_metapage)
*/
#ifdef _JFS_FIXME
if ((rc = flush_metapage(mp))) {
/*
* the write failed -- this means that the buffer
* is still assigned and the blocks are not being
* used. this seems like the best error recovery
* we can get ...
*/
goto failed;
}
#else
flush_metapage(mp);
#endif
cp += PSIZE;
nbytes -= nb;
}
ea->flag = DXD_EXTENT;
DXDsize(ea, le32_to_cpu(ealist->size));
DXDlength(ea, nblocks);
DXDaddress(ea, blkno);
/* Free up INLINE area */
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
return 0;
failed:
/* Rollback quota allocation. */
DQUOT_FREE_BLOCK(ip, nblocks);
dbFree(ip, blkno, nblocks);
return rc;
}
/*
* NAME: ea_read_inline
*
* FUNCTION: Read an inlined EA into user's buffer
*
* PARAMETERS:
* ip - Inode pointer
* ealist - Pointer to buffer to fill in with EA
*
* RETURNS: 0
*/
static int ea_read_inline(struct inode *ip, struct jfs_ea_list *ealist)
{
struct jfs_inode_info *ji = JFS_IP(ip);
int ea_size = sizeDXD(&ji->ea);
if (ea_size == 0) {
ealist->size = 0;
return 0;
}
/* Sanity Check */
if ((sizeDXD(&ji->ea) > sizeof (ji->i_inline_ea)))
return -EIO;
if (le32_to_cpu(((struct jfs_ea_list *) &ji->i_inline_ea)->size)
!= ea_size)
return -EIO;
memcpy(ealist, ji->i_inline_ea, ea_size);
return 0;
}
/*
* NAME: ea_read
*
* FUNCTION: copy EA data into user's buffer
*
* PARAMETERS:
* ip - Inode pointer
* ealist - Pointer to buffer to fill in with EA
*
* NOTES: If EA is inline calls ea_read_inline() to copy EA.
*
* RETURNS: 0 for success; other indicates failure
*/
static int ea_read(struct inode *ip, struct jfs_ea_list *ealist)
{
struct super_block *sb = ip->i_sb;
struct jfs_inode_info *ji = JFS_IP(ip);
struct jfs_sb_info *sbi = JFS_SBI(sb);
int nblocks;
s64 blkno;
char *cp = (char *) ealist;
int i;
int nbytes, nb;
s32 bytes_to_read;
struct metapage *mp;
/* quick check for in-line EA */
if (ji->ea.flag & DXD_INLINE)
return ea_read_inline(ip, ealist);
nbytes = sizeDXD(&ji->ea);
if (!nbytes) {
jfs_error(sb, "ea_read: nbytes is 0");
return -EIO;
}
/*
* Figure out how many blocks were allocated when this EA list was
* originally written to disk.
*/
nblocks = lengthDXD(&ji->ea) << sbi->l2nbperpage;
blkno = addressDXD(&ji->ea) << sbi->l2nbperpage;
/*
* I have found the disk blocks which were originally used to store
* the FEALIST. now i loop over each contiguous block copying the
* data into the buffer.
*/
for (i = 0; i < nblocks; i += sbi->nbperpage) {
/*
* Determine how many bytes for this request, and round up to
* the nearest aggregate block size
*/
nb = min(PSIZE, nbytes);
bytes_to_read =
((((nb + sb->s_blocksize - 1)) >> sb->s_blocksize_bits))
<< sb->s_blocksize_bits;
if (!(mp = read_metapage(ip, blkno + i, bytes_to_read, 1)))
return -EIO;
memcpy(cp, mp->data, nb);
release_metapage(mp);
cp += PSIZE;
nbytes -= nb;
}
return 0;
}
/*
* NAME: ea_get
*
* FUNCTION: Returns buffer containing existing extended attributes.
* The size of the buffer will be the larger of the existing
* attributes size, or min_size.
*
* The buffer, which may be inlined in the inode or in the
* page cache must be release by calling ea_release or ea_put
*
* PARAMETERS:
* inode - Inode pointer
* ea_buf - Structure to be populated with ealist and its metadata
* min_size- minimum size of buffer to be returned
*
* RETURNS: 0 for success; Other indicates failure
*/
static int ea_get(struct inode *inode, struct ea_buffer *ea_buf, int min_size)
{
struct jfs_inode_info *ji = JFS_IP(inode);
struct super_block *sb = inode->i_sb;
int size;
int ea_size = sizeDXD(&ji->ea);
int blocks_needed, current_blocks;
s64 blkno;
int rc;
int quota_allocation = 0;
/* When fsck.jfs clears a bad ea, it doesn't clear the size */
if (ji->ea.flag == 0)
ea_size = 0;
if (ea_size == 0) {
if (min_size == 0) {
ea_buf->flag = 0;
ea_buf->max_size = 0;
ea_buf->xattr = NULL;
return 0;
}
if ((min_size <= sizeof (ji->i_inline_ea)) &&
(ji->mode2 & INLINEEA)) {
ea_buf->flag = EA_INLINE | EA_NEW;
ea_buf->max_size = sizeof (ji->i_inline_ea);
ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
DXDlength(&ea_buf->new_ea, 0);
DXDaddress(&ea_buf->new_ea, 0);
ea_buf->new_ea.flag = DXD_INLINE;
DXDsize(&ea_buf->new_ea, min_size);
return 0;
}
current_blocks = 0;
} else if (ji->ea.flag & DXD_INLINE) {
if (min_size <= sizeof (ji->i_inline_ea)) {
ea_buf->flag = EA_INLINE;
ea_buf->max_size = sizeof (ji->i_inline_ea);
ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
goto size_check;
}
current_blocks = 0;
} else {
if (!(ji->ea.flag & DXD_EXTENT)) {
jfs_error(sb, "ea_get: invalid ea.flag)");
return -EIO;
}
current_blocks = (ea_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
}
size = max(min_size, ea_size);
if (size > PSIZE) {
/*
* To keep the rest of the code simple. Allocate a
* contiguous buffer to work with
*/
ea_buf->xattr = kmalloc(size, GFP_KERNEL);
if (ea_buf->xattr == NULL)
return -ENOMEM;
ea_buf->flag = EA_MALLOC;
ea_buf->max_size = (size + sb->s_blocksize - 1) &
~(sb->s_blocksize - 1);
if (ea_size == 0)
return 0;
if ((rc = ea_read(inode, ea_buf->xattr))) {
kfree(ea_buf->xattr);
ea_buf->xattr = NULL;
return rc;
}
goto size_check;
}
blocks_needed = (min_size + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
if (blocks_needed > current_blocks) {
/* Allocate new blocks to quota. */
if (DQUOT_ALLOC_BLOCK(inode, blocks_needed))
return -EDQUOT;
quota_allocation = blocks_needed;
rc = dbAlloc(inode, INOHINT(inode), (s64) blocks_needed,
&blkno);
if (rc)
goto clean_up;
DXDlength(&ea_buf->new_ea, blocks_needed);
DXDaddress(&ea_buf->new_ea, blkno);
ea_buf->new_ea.flag = DXD_EXTENT;
DXDsize(&ea_buf->new_ea, min_size);
ea_buf->flag = EA_EXTENT | EA_NEW;
ea_buf->mp = get_metapage(inode, blkno,
blocks_needed << sb->s_blocksize_bits,
1);
if (ea_buf->mp == NULL) {
dbFree(inode, blkno, (s64) blocks_needed);
rc = -EIO;
goto clean_up;
}
ea_buf->xattr = ea_buf->mp->data;
ea_buf->max_size = (min_size + sb->s_blocksize - 1) &
~(sb->s_blocksize - 1);
if (ea_size == 0)
return 0;
if ((rc = ea_read(inode, ea_buf->xattr))) {
discard_metapage(ea_buf->mp);
dbFree(inode, blkno, (s64) blocks_needed);
goto clean_up;
}
goto size_check;
}
ea_buf->flag = EA_EXTENT;
ea_buf->mp = read_metapage(inode, addressDXD(&ji->ea),
lengthDXD(&ji->ea) << sb->s_blocksize_bits,
1);
if (ea_buf->mp == NULL) {
rc = -EIO;
goto clean_up;
}
ea_buf->xattr = ea_buf->mp->data;
ea_buf->max_size = (ea_size + sb->s_blocksize - 1) &
~(sb->s_blocksize - 1);
size_check:
if (EALIST_SIZE(ea_buf->xattr) != ea_size) {
printk(KERN_ERR "ea_get: invalid extended attribute\n");
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_ADDRESS, 16, 1,
ea_buf->xattr, ea_size, 1);
ea_release(inode, ea_buf);
rc = -EIO;
goto clean_up;
}
return ea_size;
clean_up:
/* Rollback quota allocation */
if (quota_allocation)
DQUOT_FREE_BLOCK(inode, quota_allocation);
return (rc);
}
static void ea_release(struct inode *inode, struct ea_buffer *ea_buf)
{
if (ea_buf->flag & EA_MALLOC)
kfree(ea_buf->xattr);
else if (ea_buf->flag & EA_EXTENT) {
assert(ea_buf->mp);
release_metapage(ea_buf->mp);
if (ea_buf->flag & EA_NEW)
dbFree(inode, addressDXD(&ea_buf->new_ea),
lengthDXD(&ea_buf->new_ea));
}
}
static int ea_put(tid_t tid, struct inode *inode, struct ea_buffer *ea_buf,
int new_size)
{
struct jfs_inode_info *ji = JFS_IP(inode);
unsigned long old_blocks, new_blocks;
int rc = 0;
if (new_size == 0) {
ea_release(inode, ea_buf);
ea_buf = NULL;
} else if (ea_buf->flag & EA_INLINE) {
assert(new_size <= sizeof (ji->i_inline_ea));
ji->mode2 &= ~INLINEEA;
ea_buf->new_ea.flag = DXD_INLINE;
DXDsize(&ea_buf->new_ea, new_size);
DXDaddress(&ea_buf->new_ea, 0);
DXDlength(&ea_buf->new_ea, 0);
} else if (ea_buf->flag & EA_MALLOC) {
rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
kfree(ea_buf->xattr);
} else if (ea_buf->flag & EA_NEW) {
/* We have already allocated a new dxd */
flush_metapage(ea_buf->mp);
} else {
/* ->xattr must point to original ea's metapage */
rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
discard_metapage(ea_buf->mp);
}
if (rc)
return rc;
old_blocks = new_blocks = 0;
if (ji->ea.flag & DXD_EXTENT) {
invalidate_dxd_metapages(inode, ji->ea);
old_blocks = lengthDXD(&ji->ea);
}
if (ea_buf) {
txEA(tid, inode, &ji->ea, &ea_buf->new_ea);
if (ea_buf->new_ea.flag & DXD_EXTENT) {
new_blocks = lengthDXD(&ea_buf->new_ea);
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
}
ji->ea = ea_buf->new_ea;
} else {
txEA(tid, inode, &ji->ea, NULL);
if (ji->ea.flag & DXD_INLINE)
ji->mode2 |= INLINEEA;
ji->ea.flag = 0;
ji->ea.size = 0;
}
/* If old blocks exist, they must be removed from quota allocation. */
if (old_blocks)
DQUOT_FREE_BLOCK(inode, old_blocks);
inode->i_ctime = CURRENT_TIME;
return 0;
}
/*
* can_set_system_xattr
*
* This code is specific to the system.* namespace. It contains policy
* which doesn't belong in the main xattr codepath.
*/
static int can_set_system_xattr(struct inode *inode, const char *name,
const void *value, size_t value_len)
{
#ifdef CONFIG_JFS_POSIX_ACL
struct posix_acl *acl;
int rc;
if (!is_owner_or_cap(inode))
return -EPERM;
/*
* POSIX_ACL_XATTR_ACCESS is tied to i_mode
*/
if (strcmp(name, POSIX_ACL_XATTR_ACCESS) == 0) {
acl = posix_acl_from_xattr(value, value_len);
if (IS_ERR(acl)) {
rc = PTR_ERR(acl);
printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
rc);
return rc;
}
if (acl) {
mode_t mode = inode->i_mode;
rc = posix_acl_equiv_mode(acl, &mode);
posix_acl_release(acl);
if (rc < 0) {
printk(KERN_ERR
"posix_acl_equiv_mode returned %d\n",
rc);
return rc;
}
inode->i_mode = mode;
mark_inode_dirty(inode);
}
/*
* We're changing the ACL. Get rid of the cached one
*/
acl =JFS_IP(inode)->i_acl;
if (acl != JFS_ACL_NOT_CACHED)
posix_acl_release(acl);
JFS_IP(inode)->i_acl = JFS_ACL_NOT_CACHED;
return 0;
} else if (strcmp(name, POSIX_ACL_XATTR_DEFAULT) == 0) {
acl = posix_acl_from_xattr(value, value_len);
if (IS_ERR(acl)) {
rc = PTR_ERR(acl);
printk(KERN_ERR "posix_acl_from_xattr returned %d\n",
rc);
return rc;
}
posix_acl_release(acl);
/*
* We're changing the default ACL. Get rid of the cached one
*/
acl =JFS_IP(inode)->i_default_acl;
if (acl && (acl != JFS_ACL_NOT_CACHED))
posix_acl_release(acl);
JFS_IP(inode)->i_default_acl = JFS_ACL_NOT_CACHED;
return 0;
}
#endif /* CONFIG_JFS_POSIX_ACL */
return -EOPNOTSUPP;
}
/*
* Most of the permission checking is done by xattr_permission in the vfs.
* The local file system is responsible for handling the system.* namespace.
* We also need to verify that this is a namespace that we recognize.
*/
static int can_set_xattr(struct inode *inode, const char *name,
const void *value, size_t value_len)
{
if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
return can_set_system_xattr(inode, name, value, value_len);
/*
* Don't allow setting an attribute in an unknown namespace.
*/
if (strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) &&
strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) &&
strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) &&
strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN))
return -EOPNOTSUPP;
return 0;
}
int __jfs_setxattr(tid_t tid, struct inode *inode, const char *name,
const void *value, size_t value_len, int flags)
{
struct jfs_ea_list *ealist;
struct jfs_ea *ea, *old_ea = NULL, *next_ea = NULL;
struct ea_buffer ea_buf;
int old_ea_size = 0;
int xattr_size;
int new_size;
int namelen = strlen(name);
char *os2name = NULL;
int found = 0;
int rc;
int length;
if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
GFP_KERNEL);
if (!os2name)
return -ENOMEM;
strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
name = os2name;
namelen -= XATTR_OS2_PREFIX_LEN;
}
down_write(&JFS_IP(inode)->xattr_sem);
xattr_size = ea_get(inode, &ea_buf, 0);
if (xattr_size < 0) {
rc = xattr_size;
goto out;
}
again:
ealist = (struct jfs_ea_list *) ea_buf.xattr;
new_size = sizeof (struct jfs_ea_list);
if (xattr_size) {
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist);
ea = NEXT_EA(ea)) {
if ((namelen == ea->namelen) &&
(memcmp(name, ea->name, namelen) == 0)) {
found = 1;
if (flags & XATTR_CREATE) {
rc = -EEXIST;
goto release;
}
old_ea = ea;
old_ea_size = EA_SIZE(ea);
next_ea = NEXT_EA(ea);
} else
new_size += EA_SIZE(ea);
}
}
if (!found) {
if (flags & XATTR_REPLACE) {
rc = -ENODATA;
goto release;
}
if (value == NULL) {
rc = 0;
goto release;
}
}
if (value)
new_size += sizeof (struct jfs_ea) + namelen + 1 + value_len;
if (new_size > ea_buf.max_size) {
/*
* We need to allocate more space for merged ea list.
* We should only have loop to again: once.
*/
ea_release(inode, &ea_buf);
xattr_size = ea_get(inode, &ea_buf, new_size);
if (xattr_size < 0) {
rc = xattr_size;
goto out;
}
goto again;
}
/* Remove old ea of the same name */
if (found) {
/* number of bytes following target EA */
length = (char *) END_EALIST(ealist) - (char *) next_ea;
if (length > 0)
memmove(old_ea, next_ea, length);
xattr_size -= old_ea_size;
}
/* Add new entry to the end */
if (value) {
if (xattr_size == 0)
/* Completely new ea list */
xattr_size = sizeof (struct jfs_ea_list);
ea = (struct jfs_ea *) ((char *) ealist + xattr_size);
ea->flag = 0;
ea->namelen = namelen;
ea->valuelen = (cpu_to_le16(value_len));
memcpy(ea->name, name, namelen);
ea->name[namelen] = 0;
if (value_len)
memcpy(&ea->name[namelen + 1], value, value_len);
xattr_size += EA_SIZE(ea);
}
/* DEBUG - If we did this right, these number match */
if (xattr_size != new_size) {
printk(KERN_ERR
"jfs_xsetattr: xattr_size = %d, new_size = %d\n",
xattr_size, new_size);
rc = -EINVAL;
goto release;
}
/*
* If we're left with an empty list, there's no ea
*/
if (new_size == sizeof (struct jfs_ea_list))
new_size = 0;
ealist->size = cpu_to_le32(new_size);
rc = ea_put(tid, inode, &ea_buf, new_size);
goto out;
release:
ea_release(inode, &ea_buf);
out:
up_write(&JFS_IP(inode)->xattr_sem);
kfree(os2name);
return rc;
}
int jfs_setxattr(struct dentry *dentry, const char *name, const void *value,
size_t value_len, int flags)
{
struct inode *inode = dentry->d_inode;
struct jfs_inode_info *ji = JFS_IP(inode);
int rc;
tid_t tid;
if ((rc = can_set_xattr(inode, name, value, value_len)))
return rc;
if (value == NULL) { /* empty EA, do not remove */
value = "";
value_len = 0;
}
tid = txBegin(inode->i_sb, 0);
mutex_lock(&ji->commit_mutex);
rc = __jfs_setxattr(tid, dentry->d_inode, name, value, value_len,
flags);
if (!rc)
rc = txCommit(tid, 1, &inode, 0);
txEnd(tid);
mutex_unlock(&ji->commit_mutex);
return rc;
}
ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
size_t buf_size)
{
struct jfs_ea_list *ealist;
struct jfs_ea *ea;
struct ea_buffer ea_buf;
int xattr_size;
ssize_t size;
int namelen = strlen(name);
char *os2name = NULL;
char *value;
if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
GFP_KERNEL);
if (!os2name)
return -ENOMEM;
strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
name = os2name;
namelen -= XATTR_OS2_PREFIX_LEN;
}
down_read(&JFS_IP(inode)->xattr_sem);
xattr_size = ea_get(inode, &ea_buf, 0);
if (xattr_size < 0) {
size = xattr_size;
goto out;
}
if (xattr_size == 0)
goto not_found;
ealist = (struct jfs_ea_list *) ea_buf.xattr;
/* Find the named attribute */
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea))
if ((namelen == ea->namelen) &&
memcmp(name, ea->name, namelen) == 0) {
/* Found it */
size = le16_to_cpu(ea->valuelen);
if (!data)
goto release;
else if (size > buf_size) {
size = -ERANGE;
goto release;
}
value = ((char *) &ea->name) + ea->namelen + 1;
memcpy(data, value, size);
goto release;
}
not_found:
size = -ENODATA;
release:
ea_release(inode, &ea_buf);
out:
up_read(&JFS_IP(inode)->xattr_sem);
kfree(os2name);
return size;
}
ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
size_t buf_size)
{
int err;
err = __jfs_getxattr(dentry->d_inode, name, data, buf_size);
return err;
}
/*
* No special permissions are needed to list attributes except for trusted.*
*/
static inline int can_list(struct jfs_ea *ea)
{
return (strncmp(ea->name, XATTR_TRUSTED_PREFIX,
XATTR_TRUSTED_PREFIX_LEN) ||
capable(CAP_SYS_ADMIN));
}
ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
{
struct inode *inode = dentry->d_inode;
char *buffer;
ssize_t size = 0;
int xattr_size;
struct jfs_ea_list *ealist;
struct jfs_ea *ea;
struct ea_buffer ea_buf;
down_read(&JFS_IP(inode)->xattr_sem);
xattr_size = ea_get(inode, &ea_buf, 0);
if (xattr_size < 0) {
size = xattr_size;
goto out;
}
if (xattr_size == 0)
goto release;
ealist = (struct jfs_ea_list *) ea_buf.xattr;
/* compute required size of list */
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
if (can_list(ea))
size += name_size(ea) + 1;
}
if (!data)
goto release;
if (size > buf_size) {
size = -ERANGE;
goto release;
}
/* Copy attribute names to buffer */
buffer = data;
for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
if (can_list(ea)) {
int namelen = copy_name(buffer, ea);
buffer += namelen + 1;
}
}
release:
ea_release(inode, &ea_buf);
out:
up_read(&JFS_IP(inode)->xattr_sem);
return size;
}
int jfs_removexattr(struct dentry *dentry, const char *name)
{
struct inode *inode = dentry->d_inode;
struct jfs_inode_info *ji = JFS_IP(inode);
int rc;
tid_t tid;
if ((rc = can_set_xattr(inode, name, NULL, 0)))
return rc;
tid = txBegin(inode->i_sb, 0);
mutex_lock(&ji->commit_mutex);
rc = __jfs_setxattr(tid, dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
if (!rc)
rc = txCommit(tid, 1, &inode, 0);
txEnd(tid);
mutex_unlock(&ji->commit_mutex);
return rc;
}
#ifdef CONFIG_JFS_SECURITY
int jfs_init_security(tid_t tid, struct inode *inode, struct inode *dir)
{
int rc;
size_t len;
void *value;
char *suffix;
char *name;
rc = security_inode_init_security(inode, dir, &suffix, &value, &len);
if (rc) {
if (rc == -EOPNOTSUPP)
return 0;
return rc;
}
name = kmalloc(XATTR_SECURITY_PREFIX_LEN + 1 + strlen(suffix),
GFP_NOFS);
if (!name) {
rc = -ENOMEM;
goto kmalloc_failed;
}
strcpy(name, XATTR_SECURITY_PREFIX);
strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
rc = __jfs_setxattr(tid, inode, name, value, len, 0);
kfree(name);
kmalloc_failed:
kfree(suffix);
kfree(value);
return rc;
}
#endif
Reference in New Issue View Git Blame Copy Permalink