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sys/fs/ext2fs/ext2_acl.c

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/*-
* Copyright (c) 2017, Fedor Uporov
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/vnode.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/endian.h>
#include <sys/conf.h>
#include <sys/mount.h>
#include <sys/extattr.h>
#include <fs/ext2fs/fs.h>
#include <fs/ext2fs/ext2fs.h>
#include <fs/ext2fs/inode.h>
#include <fs/ext2fs/ext2_acl.h>
#include <fs/ext2fs/ext2_extattr.h>
#include <fs/ext2fs/ext2_extern.h>
#include <fs/ext2fs/ext2_dinode.h>
#include <fs/ext2fs/ext2_mount.h>
void
ext2_sync_acl_from_inode(struct inode *ip, struct acl *acl)
{
struct acl_entry *acl_mask, *acl_group_obj;
int i;
/*
* Update ACL_USER_OBJ, ACL_OTHER, but simply identify ACL_MASK
* and ACL_GROUP_OBJ for use after we know whether ACL_MASK is
* present.
*/
acl_mask = NULL;
acl_group_obj = NULL;
for (i = 0; i < acl->acl_cnt; i++) {
switch (acl->acl_entry[i].ae_tag) {
case ACL_USER_OBJ:
acl->acl_entry[i].ae_perm = acl_posix1e_mode_to_perm(
ACL_USER_OBJ, ip->i_mode);
acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
break;
case ACL_GROUP_OBJ:
acl_group_obj = &acl->acl_entry[i];
acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
break;
case ACL_OTHER:
acl->acl_entry[i].ae_perm = acl_posix1e_mode_to_perm(
ACL_OTHER, ip->i_mode);
acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
break;
case ACL_MASK:
acl_mask = &acl->acl_entry[i];
acl->acl_entry[i].ae_id = ACL_UNDEFINED_ID;
break;
case ACL_USER:
case ACL_GROUP:
break;
default:
panic("ext2_sync_acl_from_inode(): bad ae_tag");
}
}
if (acl_group_obj == NULL)
panic("ext2_sync_acl_from_inode(): no ACL_GROUP_OBJ");
if (acl_mask == NULL) {
/*
* There is no ACL_MASK, so update ACL_GROUP_OBJ.
*/
acl_group_obj->ae_perm = acl_posix1e_mode_to_perm(
ACL_GROUP_OBJ, ip->i_mode);
} else {
/*
* Update the ACL_MASK entry instead of ACL_GROUP_OBJ.
*/
acl_mask->ae_perm = acl_posix1e_mode_to_perm(ACL_GROUP_OBJ,
ip->i_mode);
}
}
static void
ext2_sync_inode_from_acl(struct acl *acl, struct inode *ip)
{
ip->i_mode &= ACL_PRESERVE_MASK;
ip->i_mode |= acl_posix1e_acl_to_mode(acl);
}
/*
* Convert from filesystem to in-memory representation.
*/
static int
ext4_acl_from_disk(char *value, size_t size, struct acl *acl)
{
const char *end = value + size;
int n, count, s;
if (((struct ext2_acl_header *)value)->a_version != EXT4_ACL_VERSION)
return (EINVAL);
if (!value || size < sizeof(struct ext2_acl_header))
return (EINVAL);
s = size - sizeof(struct ext2_acl_header);
s -= 4 * sizeof(struct ext2_acl_entry_short);
if (s < 0)
if ((size - sizeof(struct ext2_acl_header)) %
sizeof(struct ext2_acl_entry_short))
count = -1;
else
pfgUnsubmitted
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size is unsigned, perhaps there is a risk for it to become negative here?

pfg: size is unsigned, perhaps there is a risk for it to become negative here?
fsuAuthorUnsubmitted
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It should be impossible, because the acl header should present in all cases.

fsu: It should be impossible, because the acl header should present in all cases.
pfgUnsubmitted
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Prceisely, perhaps I read it wrong but, what happens in line 144 and the case where someone specified
size < sizeof(struct ext2_acl_header) ?

pfg: Prceisely, perhaps I read it wrong but, what happens in line 144 and the case where someone…
fsuAuthorUnsubmitted
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Sorry, may be my previous answer was too short:
ext4_acl_from_disk(char *value, size_t size, struct acl *acl)
{
const char *end = value + size;
int n, count;

if (!value || size < sizeof(struct ext2_acl_header))

		return (EINVAL);

if (((struct ext2_acl_header *)value)->a_version != EXT4_ACL_VERSION)

		return (EINVAL);

value = value + sizeof(struct ext2_acl_header);
count = ext2_acl_count(size)

...
So, as you can see it is impossible
to call ext2_acl_count() with size value less than sizeof(struct ext2_acl_header).
If you talking about somebady...
I hope somebady understands what he doing because it is internal (static) function.
Also, if it is critical for you, I can change size_t to signed and add appropriate check.

fsu: Sorry, may be my previous answer was too short: ext4_acl_from_disk(char *value, size_t size…
pfgUnsubmitted
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OK .. I see now, sorry: I was looking at the local function only.

Perhaps it would be clearer if we pass the subtracted value instead of doing the subtraction within ext2_acl_count()., but it's OK as it is.

pfg: OK .. I see now, sorry: I was looking at the local function only. Perhaps it would be clearer…
count = (size - sizeof(struct ext2_acl_header)) /
sizeof(struct ext2_acl_entry_short);
else
if (s % sizeof(struct ext2_acl_entry))
pfgUnsubmitted
Not Done
Inline Actions

Use parenthesis with return, same on line 153.

pfg: Use parenthesis with return, same on line 153.
count = -1;
else
count = s / sizeof(struct ext2_acl_entry) + 4;
if (count <= 0 || count > acl->acl_maxcnt)
return (EINVAL);
value = value + sizeof(struct ext2_acl_header);
for (n = 0; n < count; n++) {
struct ext2_acl_entry *entry = (struct ext2_acl_entry *)value;
if ((char *)value + sizeof(struct ext2_acl_entry_short) > end)
return (EINVAL);
acl->acl_entry[n].ae_tag = entry->ae_tag;
acl->acl_entry[n].ae_perm = entry->ae_perm;
switch (acl->acl_entry[n].ae_tag) {
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
value = (char *)value + sizeof(struct ext2_acl_entry_short);
break;
case ACL_USER:
value = (char *)value + sizeof(struct ext2_acl_entry);
if ((char *)value > end)
return (EINVAL);
acl->acl_entry[n].ae_id = entry->ae_id;
break;
case ACL_GROUP:
value = (char *)value + sizeof(struct ext2_acl_entry);
if ((char *)value > end)
return (EINVAL);
acl->acl_entry[n].ae_id = entry->ae_id;
break;
default:
return (EINVAL);
}
}
if (value != end)
return (EINVAL);
acl->acl_cnt = count;
return (0);
}
static int
ext2_getacl_posix1e(struct vop_getacl_args *ap)
{
int attrnamespace;
const char *attrname;
char *value;
int len;
int error;
len = sizeof(*ap->a_aclp) + sizeof(struct ext2_acl_header);
value = malloc(len, M_ACL, M_WAITOK);
if (!value)
return (ENOMEM);
switch (ap->a_type) {
case ACL_TYPE_DEFAULT:
attrnamespace = POSIX1E_ACL_DEFAULT_EXTATTR_NAMESPACE;
attrname = POSIX1E_ACL_DEFAULT_EXTATTR_NAME;
break;
case ACL_TYPE_ACCESS:
attrnamespace = POSIX1E_ACL_ACCESS_EXTATTR_NAMESPACE;
attrname = POSIX1E_ACL_ACCESS_EXTATTR_NAME;
break;
default:
return (EINVAL);
}
error = vn_extattr_get(ap->a_vp, IO_NODELOCKED, attrnamespace, attrname,
&len, value, ap->a_td);
switch (error) {
case ENOATTR:
switch (ap->a_type) {
case ACL_TYPE_ACCESS:
ap->a_aclp->acl_cnt = 3;
ap->a_aclp->acl_entry[0].ae_tag = ACL_USER_OBJ;
ap->a_aclp->acl_entry[0].ae_id = ACL_UNDEFINED_ID;
ap->a_aclp->acl_entry[0].ae_perm = ACL_PERM_NONE;
ap->a_aclp->acl_entry[1].ae_tag = ACL_GROUP_OBJ;
ap->a_aclp->acl_entry[1].ae_id = ACL_UNDEFINED_ID;
ap->a_aclp->acl_entry[1].ae_perm = ACL_PERM_NONE;
ap->a_aclp->acl_entry[2].ae_tag = ACL_OTHER;
ap->a_aclp->acl_entry[2].ae_id = ACL_UNDEFINED_ID;
ap->a_aclp->acl_entry[2].ae_perm = ACL_PERM_NONE;
break;
case ACL_TYPE_DEFAULT:
ap->a_aclp->acl_cnt = 0;
break;
}
case 0:
if (!error) {
error = ext4_acl_from_disk(value, len, ap->a_aclp);
if (error)
goto out;
}
if (error == ENOATTR)
error = 0;
if (ap->a_type == ACL_TYPE_ACCESS)
ext2_sync_acl_from_inode(VTOI(ap->a_vp), ap->a_aclp);
default:
break;
}
out:
free(value, M_TEMP);
return (error);
}
int
ext2_getacl(struct vop_getacl_args *ap)
{
if (((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0) ||
((ap->a_vp->v_mount->mnt_flag & MNT_NFS4ACLS) == 1))
return (EOPNOTSUPP);
if (ap->a_type == ACL_TYPE_NFS4)
return (ENOTSUP);
return (ext2_getacl_posix1e(ap));
}
/*
* Convert from in-memory to filesystem representation.
*/
static int
ext4_acl_to_disk(const struct acl *acl, size_t *size, char *value)
{
struct ext2_acl_header *ext_acl;
int disk_size;
char *e;
size_t n;
if (acl->acl_cnt <= 4)
disk_size = sizeof(struct ext2_acl_header) +
acl->acl_cnt * sizeof(struct ext2_acl_entry_short);
else
disk_size = sizeof(struct ext2_acl_header) +
4 * sizeof(struct ext2_acl_entry_short) +
(acl->acl_cnt - 4) * sizeof(struct ext2_acl_entry);
if (disk_size > *size)
return (EINVAL);
*size = disk_size;
ext_acl = (struct ext2_acl_header *)value;
ext_acl->a_version = EXT4_ACL_VERSION;
e = (char *)ext_acl + sizeof(struct ext2_acl_header);
for (n = 0; n < acl->acl_cnt; n++) {
const struct acl_entry *acl_e = &acl->acl_entry[n];
struct ext2_acl_entry *entry = (struct ext2_acl_entry *)e;
entry->ae_tag = acl_e->ae_tag;
entry->ae_perm = acl_e->ae_perm;
switch (acl_e->ae_tag) {
case ACL_USER:
entry->ae_id = acl_e->ae_id;
e += sizeof(struct ext2_acl_entry);
break;
case ACL_GROUP:
entry->ae_id = acl_e->ae_id;
e += sizeof(struct ext2_acl_entry);
break;
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_MASK:
case ACL_OTHER:
e += sizeof(struct ext2_acl_entry_short);
break;
default:
return (EINVAL);
}
}
return (0);
}
static int
ext2_setacl_posix1e(struct vop_setacl_args *ap)
{
struct inode *ip = VTOI(ap->a_vp);
char *value;
size_t len;
int error;
if ((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0)
return (EINVAL);
/*
* If this is a set operation rather than a delete operation,
* invoke VOP_ACLCHECK() on the passed ACL to determine if it is
* valid for the target. This will include a check on ap->a_type.
*/
if (ap->a_aclp != NULL) {
/*
* Set operation.
*/
error = VOP_ACLCHECK(ap->a_vp, ap->a_type, ap->a_aclp,
ap->a_cred, ap->a_td);
if (error)
return (error);
} else {
/*
* Delete operation.
* POSIX.1e allows only deletion of the default ACL on a
* directory (ACL_TYPE_DEFAULT).
*/
if (ap->a_type != ACL_TYPE_DEFAULT)
return (EINVAL);
if (ap->a_vp->v_type != VDIR)
return (ENOTDIR);
}
if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
return (EROFS);
/*
* Authorize the ACL operation.
*/
if (ip->i_flags & (IMMUTABLE | APPEND))
return (EPERM);
/*
* Must hold VADMIN (be file owner) or have appropriate privilege.
*/
if ((error = VOP_ACCESS(ap->a_vp, VADMIN, ap->a_cred, ap->a_td)))
return (error);
switch (ap->a_type) {
case ACL_TYPE_ACCESS:
len = sizeof(*ap->a_aclp) + sizeof(struct ext2_acl_header);
value = malloc(len, M_ACL, M_WAITOK | M_ZERO);
error = ext4_acl_to_disk(ap->a_aclp, &len, value);
if (error == 0)
error = vn_extattr_set(ap->a_vp, IO_NODELOCKED,
POSIX1E_ACL_ACCESS_EXTATTR_NAMESPACE,
POSIX1E_ACL_ACCESS_EXTATTR_NAME, len,
value, ap->a_td);
free(value, M_ACL);
break;
case ACL_TYPE_DEFAULT:
if (ap->a_aclp == NULL) {
error = vn_extattr_rm(ap->a_vp, IO_NODELOCKED,
POSIX1E_ACL_DEFAULT_EXTATTR_NAMESPACE,
POSIX1E_ACL_DEFAULT_EXTATTR_NAME, ap->a_td);
/*
* Attempting to delete a non-present default ACL
* will return success for portability purposes.
* (TRIX)
*
* XXX: Note that since we can't distinguish
* "that EA is not supported" from "that EA is not
* defined", the success case here overlaps the
* the ENOATTR->EOPNOTSUPP case below.
*/
if (error == ENOATTR)
error = 0;
} else {
len = sizeof(*ap->a_aclp) + sizeof(struct ext2_acl_header);
value = malloc(len, M_ACL, M_WAITOK | M_ZERO);
error = ext4_acl_to_disk(ap->a_aclp, &len, value);
if (error == 0)
error = vn_extattr_set(ap->a_vp, IO_NODELOCKED,
POSIX1E_ACL_DEFAULT_EXTATTR_NAMESPACE,
POSIX1E_ACL_DEFAULT_EXTATTR_NAME, len,
value, ap->a_td);
free(value, M_ACL);
}
break;
default:
error = EINVAL;
}
/*
* Map lack of attribute definition in UFS_EXTATTR into lack of
* support for ACLs on the filesystem.
*/
if (error == ENOATTR)
return (EOPNOTSUPP);
if (error != 0)
return (error);
if (ap->a_type == ACL_TYPE_ACCESS) {
/*
* Now that the EA is successfully updated, update the
* inode and mark it as changed.
*/
ext2_sync_inode_from_acl(ap->a_aclp, ip);
ip->i_flag |= IN_CHANGE;
error = ext2_update(ip->i_vnode, 1);
}
VN_KNOTE_UNLOCKED(ap->a_vp, NOTE_ATTRIB);
return (error);
}
int
ext2_setacl(struct vop_setacl_args *ap)
{
if (((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0) ||
((ap->a_vp->v_mount->mnt_flag & MNT_NFS4ACLS) == 1))
return (EOPNOTSUPP);
if (ap->a_type == ACL_TYPE_NFS4)
return (ENOTSUP);
return (ext2_setacl_posix1e(ap));
}
/*
* Check the validity of an ACL for a file.
*/
int
ext2_aclcheck(struct vop_aclcheck_args *ap)
{
if (((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0) ||
((ap->a_vp->v_mount->mnt_flag & MNT_NFS4ACLS) == 1))
return (EOPNOTSUPP);
if (ap->a_type == ACL_TYPE_NFS4)
return (ENOTSUP);
if ((ap->a_vp->v_mount->mnt_flag & MNT_ACLS) == 0)
return (EINVAL);
/*
* Verify we understand this type of ACL, and that it applies
* to this kind of object.
* Rely on the acl_posix1e_check() routine to verify the contents.
*/
switch (ap->a_type) {
case ACL_TYPE_ACCESS:
break;
case ACL_TYPE_DEFAULT:
if (ap->a_vp->v_type != VDIR)
return (EINVAL);
break;
default:
return (EINVAL);
}
return (acl_posix1e_check(ap->a_aclp));
}
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