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linux/fs/cifs/xattr.c
Santosh Nayak b0f8ef202e cifs: possible memory leak in xattr. 
Memory is allocated irrespective of whether CIFS_ACL is configured
or not. But free is happenning only if CIFS_ACL is set. This is a
possible memory leak scenario.

Fix is:
Allocate and free memory only if CIFS_ACL is configured.

Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
Reviewed-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2012-03-06 21:46:53 -06:00

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/*
* fs/cifs/xattr.c
*
* Copyright (c) International Business Machines Corp., 2003, 2007
* Author(s): Steve French (sfrench@us.ibm.com)
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/posix_acl_xattr.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#define MAX_EA_VALUE_SIZE 65535
#define CIFS_XATTR_DOS_ATTRIB "user.DosAttrib"
#define CIFS_XATTR_CIFS_ACL "system.cifs_acl"
/* BB need to add server (Samba e.g) support for security and trusted prefix */
int cifs_removexattr(struct dentry *direntry, const char *ea_name)
{
int rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path = NULL;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = GetXid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto remove_ea_exit;
}
if (ea_name == NULL) {
cFYI(1, "Null xattr names not supported");
} else if (strncmp(ea_name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)
&& (strncmp(ea_name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN))) {
cFYI(1,
"illegal xattr request %s (only user namespace supported)",
ea_name);
/* BB what if no namespace prefix? */
/* Should we just pass them to server, except for
system and perhaps security prefixes? */
} else {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto remove_ea_exit;
ea_name += XATTR_USER_PREFIX_LEN; /* skip past user. prefix */
rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, NULL,
(__u16)0, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
}
remove_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
int cifs_setxattr(struct dentry *direntry, const char *ea_name,
const void *ea_value, size_t value_size, int flags)
{
int rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = GetXid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto set_ea_exit;
}
/* return dos attributes as pseudo xattr */
/* return alt name if available as pseudo attr */
/* if proc/fs/cifs/streamstoxattr is set then
search server for EAs or streams to
returns as xattrs */
if (value_size > MAX_EA_VALUE_SIZE) {
cFYI(1, "size of EA value too large");
rc = -EOPNOTSUPP;
goto set_ea_exit;
}
if (ea_name == NULL) {
cFYI(1, "Null xattr names not supported");
} else if (strncmp(ea_name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)
== 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto set_ea_exit;
if (strncmp(ea_name, CIFS_XATTR_DOS_ATTRIB, 14) == 0)
cFYI(1, "attempt to set cifs inode metadata");
ea_name += XATTR_USER_PREFIX_LEN; /* skip past user. prefix */
rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, ea_value,
(__u16)value_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN)
== 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto set_ea_exit;
ea_name += XATTR_OS2_PREFIX_LEN; /* skip past os2. prefix */
rc = CIFSSMBSetEA(xid, pTcon, full_path, ea_name, ea_value,
(__u16)value_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, CIFS_XATTR_CIFS_ACL,
strlen(CIFS_XATTR_CIFS_ACL)) == 0) {
#ifdef CONFIG_CIFS_ACL
struct cifs_ntsd *pacl;
pacl = kmalloc(value_size, GFP_KERNEL);
if (!pacl) {
cFYI(1, "%s: Can't allocate memory for ACL",
__func__);
rc = -ENOMEM;
} else {
memcpy(pacl, ea_value, value_size);
rc = set_cifs_acl(pacl, value_size,
direntry->d_inode, full_path, CIFS_ACL_DACL);
if (rc == 0) /* force revalidate of the inode */
CIFS_I(direntry->d_inode)->time = 0;
kfree(pacl);
}
#else
cFYI(1, "Set CIFS ACL not supported yet");
#endif /* CONFIG_CIFS_ACL */
} else {
int temp;
temp = strncmp(ea_name, POSIX_ACL_XATTR_ACCESS,
strlen(POSIX_ACL_XATTR_ACCESS));
if (temp == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
ea_value, (const int)value_size,
ACL_TYPE_ACCESS, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
cFYI(1, "set POSIX ACL rc %d", rc);
#else
cFYI(1, "set POSIX ACL not supported");
#endif
} else if (strncmp(ea_name, POSIX_ACL_XATTR_DEFAULT,
strlen(POSIX_ACL_XATTR_DEFAULT)) == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBSetPosixACL(xid, pTcon, full_path,
ea_value, (const int)value_size,
ACL_TYPE_DEFAULT, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
cFYI(1, "set POSIX default ACL rc %d", rc);
#else
cFYI(1, "set default POSIX ACL not supported");
#endif
} else {
cFYI(1, "illegal xattr request %s (only user namespace"
" supported)", ea_name);
/* BB what if no namespace prefix? */
/* Should we just pass them to server, except for
system and perhaps security prefixes? */
}
}
set_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
void *ea_value, size_t buf_size)
{
ssize_t rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = GetXid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto get_ea_exit;
}
/* return dos attributes as pseudo xattr */
/* return alt name if available as pseudo attr */
if (ea_name == NULL) {
cFYI(1, "Null xattr names not supported");
} else if (strncmp(ea_name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)
== 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto get_ea_exit;
if (strncmp(ea_name, CIFS_XATTR_DOS_ATTRIB, 14) == 0) {
cFYI(1, "attempt to query cifs inode metadata");
/* revalidate/getattr then populate from inode */
} /* BB add else when above is implemented */
ea_name += XATTR_USER_PREFIX_LEN; /* skip past user. prefix */
rc = CIFSSMBQAllEAs(xid, pTcon, full_path, ea_name, ea_value,
buf_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
goto get_ea_exit;
ea_name += XATTR_OS2_PREFIX_LEN; /* skip past os2. prefix */
rc = CIFSSMBQAllEAs(xid, pTcon, full_path, ea_name, ea_value,
buf_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
} else if (strncmp(ea_name, POSIX_ACL_XATTR_ACCESS,
strlen(POSIX_ACL_XATTR_ACCESS)) == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
ea_value, buf_size, ACL_TYPE_ACCESS,
cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
#else
cFYI(1, "Query POSIX ACL not supported yet");
#endif /* CONFIG_CIFS_POSIX */
} else if (strncmp(ea_name, POSIX_ACL_XATTR_DEFAULT,
strlen(POSIX_ACL_XATTR_DEFAULT)) == 0) {
#ifdef CONFIG_CIFS_POSIX
if (sb->s_flags & MS_POSIXACL)
rc = CIFSSMBGetPosixACL(xid, pTcon, full_path,
ea_value, buf_size, ACL_TYPE_DEFAULT,
cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
#else
cFYI(1, "Query POSIX default ACL not supported yet");
#endif /* CONFIG_CIFS_POSIX */
} else if (strncmp(ea_name, CIFS_XATTR_CIFS_ACL,
strlen(CIFS_XATTR_CIFS_ACL)) == 0) {
#ifdef CONFIG_CIFS_ACL
u32 acllen;
struct cifs_ntsd *pacl;
pacl = get_cifs_acl(cifs_sb, direntry->d_inode,
full_path, &acllen);
if (IS_ERR(pacl)) {
rc = PTR_ERR(pacl);
cERROR(1, "%s: error %zd getting sec desc",
__func__, rc);
} else {
if (ea_value) {
if (acllen > buf_size)
acllen = -ERANGE;
else
memcpy(ea_value, pacl, acllen);
}
rc = acllen;
kfree(pacl);
}
#else
cFYI(1, "Query CIFS ACL not supported yet");
#endif /* CONFIG_CIFS_ACL */
} else if (strncmp(ea_name,
XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) == 0) {
cFYI(1, "Trusted xattr namespace not supported yet");
} else if (strncmp(ea_name,
XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) == 0) {
cFYI(1, "Security xattr namespace not supported yet");
} else
cFYI(1,
"illegal xattr request %s (only user namespace supported)",
ea_name);
/* We could add an additional check for streams ie
if proc/fs/cifs/streamstoxattr is set then
search server for EAs or streams to
returns as xattrs */
if (rc == -EINVAL)
rc = -EOPNOTSUPP;
get_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
{
ssize_t rc = -EOPNOTSUPP;
#ifdef CONFIG_CIFS_XATTR
int xid;
struct cifs_sb_info *cifs_sb;
struct tcon_link *tlink;
struct cifs_tcon *pTcon;
struct super_block *sb;
char *full_path;
if (direntry == NULL)
return -EIO;
if (direntry->d_inode == NULL)
return -EIO;
sb = direntry->d_inode->i_sb;
if (sb == NULL)
return -EIO;
cifs_sb = CIFS_SB(sb);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
return -EOPNOTSUPP;
tlink = cifs_sb_tlink(cifs_sb);
if (IS_ERR(tlink))
return PTR_ERR(tlink);
pTcon = tlink_tcon(tlink);
xid = GetXid();
full_path = build_path_from_dentry(direntry);
if (full_path == NULL) {
rc = -ENOMEM;
goto list_ea_exit;
}
/* return dos attributes as pseudo xattr */
/* return alt name if available as pseudo attr */
/* if proc/fs/cifs/streamstoxattr is set then
search server for EAs or streams to
returns as xattrs */
rc = CIFSSMBQAllEAs(xid, pTcon, full_path, NULL, data,
buf_size, cifs_sb->local_nls,
cifs_sb->mnt_cifs_flags &
CIFS_MOUNT_MAP_SPECIAL_CHR);
list_ea_exit:
kfree(full_path);
FreeXid(xid);
cifs_put_tlink(tlink);
#endif
return rc;
}
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