// SPDX-License-Identifier: GPL-2.0
/*
* Quota code necessary even when VFS quota support is not compiled
* into the kernel. The interesting stuff is over in dquot.c, here
* we have symbols for initial quotactl(2) handling, the sysctl(2)
* variables, etc - things needed even when quota support disabled.
*/
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/slab.h>
#include <asm/current.h>
#include <linux/uaccess.h>
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
#include <linux/writeback.h>
#include <linux/nospec.h>
#include "compat.h"
static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
qid_t id)
{
switch (cmd) {
/* these commands do not require any special privilegues */
case Q_GETFMT:
case Q_SYNC:
case Q_GETINFO:
case Q_XGETQSTAT:
case Q_XGETQSTATV:
case Q_XQUOTASYNC:
break;
/* allow to query information for dquots we "own" */
case Q_GETQUOTA:
case Q_XGETQUOTA:
if ((type == USRQUOTA && uid_eq(current_euid(), make_kuid(current_user_ns(), id))) ||
(type == GRPQUOTA && in_egroup_p(make_kgid(current_user_ns(), id))))
break;
fallthrough;
default:
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
}
return security_quotactl(cmd, type, id, sb);
}
static void quota_sync_one(struct super_block *sb, void *arg)
{
int type = *(int *)arg;
if (sb->s_qcop && sb->s_qcop->quota_sync &&
(sb->s_quota_types & (1 << type)))
sb->s_qcop->quota_sync(sb, type);
}
static int quota_sync_all(int type)
{
int ret;
ret = security_quotactl(Q_SYNC, type, 0, NULL);
if (!ret)
iterate_supers(quota_sync_one, &type);
return ret;
}
unsigned int qtype_enforce_flag(int type)
{
switch (type) {
case USRQUOTA:
return FS_QUOTA_UDQ_ENFD;
case GRPQUOTA:
return FS_QUOTA_GDQ_ENFD;
case PRJQUOTA:
return FS_QUOTA_PDQ_ENFD;
}
return 0;
}
static int quota_quotaon(struct super_block *sb, int type, qid_t id,
const struct path *path)
{
if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_enable)
return -ENOSYS;
if (sb->s_qcop->quota_enable)
return sb->s_qcop->quota_enable(sb, qtype_enforce_flag(type));
if (IS_ERR(path))
return PTR_ERR(path);
return sb->s_qcop->quota_on(sb, type, id, path);
}
static int quota_quotaoff(struct super_block *sb, int type)
{
if (!sb->s_qcop->quota_off && !sb->s_qcop->quota_disable)
return -ENOSYS;
if (sb->s_qcop->quota_disable)
return sb->s_qcop->quota_disable(sb, qtype_enforce_flag(type));
return sb->s_qcop->quota_off(sb, type);
}
static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
{
__u32 fmt;
if (!sb_has_quota_active(sb, type))
return -ESRCH;
fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
if (copy_to_user(addr, &fmt, sizeof(fmt)))
return -EFAULT;
return 0;
}
static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
{
struct qc_state state;
struct qc_type_state *tstate;
struct if_dqinfo uinfo;
int ret;
if (!sb->s_qcop->get_state)
return -ENOSYS;
ret = sb->s_qcop->get_state(sb, &state);
if (ret)
return ret;
tstate = state.s_state + type;
if (!(tstate->flags & QCI_ACCT_ENABLED))
return -ESRCH;
memset(&uinfo, 0, sizeof(uinfo));
uinfo.dqi_bgrace = tstate->spc_timelimit;
uinfo.dqi_igrace = tstate->ino_timelimit;
if (tstate->flags & QCI_SYSFILE)
uinfo.dqi_flags |= DQF_SYS_FILE;