/* * 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> 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_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) { if (sb->s_qcop && sb->s_qcop->quota_sync) sb->s_qcop->quota_sync(sb, *(int *)arg); } static int quota_sync_all(int type) { int ret; if (type >= MAXQUOTAS) return -EINVAL; ret = security_quotactl(Q_SYNC, type, 0, NULL); if (!ret) iterate_supers(quota_sync_one, &type); return ret; } static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id, struct path *path) { if (!sb->s_qcop->quota_on && !sb->s_qcop->quota_on_meta) return -ENOSYS; if (sb->s_qcop->quota_on_meta) return sb->s_qcop->quota_on_meta(sb, type, id); if (IS_ERR(path)) return PTR_ERR(path); return sb->s_qcop->quota_on(sb, type, id, path); } static int quota_getfmt(struct super_block *sb, int type, void __user *addr) { __u32 fmt; down_read(&sb_dqopt(sb)->dqptr_sem); if (!sb_has_quota_active(sb, type)) { up_read(&sb_dqopt(sb)->dqptr_sem); return -ESRCH; } fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id; up_read(&sb_dqopt(sb)->dqptr_sem); 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 if_dqinfo info; int ret; if (!sb->s_qcop->get_info) return -ENOSYS; ret = sb->s_qcop->get_info(sb, type, &info); if (!ret && copy_to_user(addr, &info, sizeof(info))) return -EFAULT; return ret; } static int quota_setinfo(struct super_block *sb, int type, void __user *addr) { struct if_dqinfo info; if (copy_from_user(&info, addr, sizeof(info))) return -EFAULT; if (!sb->s_qcop->set_info) return -ENOSYS; return sb->s_qcop->set_info(sb, type, &info); } static void copy_to_if_dqblk(struct if_dqblk *dst, struct fs_disk_quota *src) { dst->dqb_bhardlimit = src->d_blk_hardlimit; dst->dqb_bsoftlimit = src->d_blk_softlimit; dst->dqb_curspace = src->d_bcount; dst->dqb_ihardlimit = src->d_ino_hardlimit; dst->dqb_isoftlimit = src->d_ino_softlimit; dst->dqb_curinodes = src->d_icount; dst->dqb_btime = src->d_btimer; dst->dqb_itime = src->d_itimer; dst->dqb_valid = QIF_ALL; } static int quota_getquota(struct super_block *sb, int type, qid_t id, void __user *addr) { struct kqid qid; struct fs_disk_quota fdq; struct if_dqblk idq; int ret; if (!sb->s_qcop->get_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); if (!qid_valid(qid)) return -EINVAL; ret = sb->s_qcop->get_dqblk(sb, qid, &fdq); if (ret) return ret; copy_to_if_dqblk(&idq, &fdq); if (copy_to_user(addr, &idq, sizeof(idq))) return -EFAULT; return 0; } static void copy_from_if_dqblk(struct fs_disk_quota *dst, struct if_dqblk *src) { dst->d_blk_hardlimit = src->dqb_bhardlimit; dst->d_blk_softlimit = src->dqb_bsoftlimit; dst->d_bcount = src->dqb_curspace; dst->d_ino_hardlimit = src->dqb_ihardlimit; dst->d_ino_softlimit = src->dqb_isoftlimit; dst->d_icount = src->dqb_curinodes; dst->d_btimer = src->dqb_btime; dst->d_itimer = src->dqb_itime; dst->d_fieldmask = 0; if (src->dqb_valid & QIF_BLIMITS) dst->d_fieldmask |= FS_DQ_BSOFT | FS_DQ_BHARD; if (src->dqb_valid & QIF_SPACE) dst->d_fieldmask |= FS_DQ_BCOUNT; if (src->dqb_valid & QIF_ILIMITS) dst->d_fieldmask |= FS_DQ_ISOFT | FS_DQ_IHARD; if (src->dqb_valid & QIF_INODES) dst->d_fieldmask |= FS_DQ_ICOUNT; if (src->dqb_valid & QIF_BTIME) dst->d_fieldmask |= FS_DQ_BTIMER; if (src->dqb_valid & QIF_ITIME) dst->d_fieldmask |= FS_DQ_ITIMER; } static int quota_setquota(struct super_block *sb, int type, qid_t id, void __user *addr) { struct fs_disk_quota fdq; struct if_dqblk idq; struct kqid qid; if (copy_from_user(&idq, addr, sizeof(idq))) return -EFAULT; if (!sb->s_qcop->set_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); if (!qid_valid(qid)) return -EINVAL; copy_from_if_dqblk(&fdq, &idq); return sb->s_qcop->set_dqblk(sb, qid, &fdq); } static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr) { __u32 flags; if (copy_from_user(&flags, addr, sizeof(flags))) return -EFAULT; if (!sb->s_qcop->set_xstate) return -ENOSYS; return sb->s_qcop->set_xstate(sb, flags, cmd); } static int quota_getxstate(struct super_block *sb, void __user *addr) { struct fs_quota_stat fqs; int ret; if (!sb->s_qcop->get_xstate) return -ENOSYS; ret = sb->s_qcop->get_xstate(sb, &fqs); if (!ret && copy_to_user(addr, &fqs, sizeof(fqs))) return -EFAULT; return ret; } static int quota_setxquota(struct super_block *sb, int type, qid_t id, void __user *addr) { struct fs_disk_quota fdq; struct kqid qid; if (copy_from_user(&fdq, addr, sizeof(fdq))) return -EFAULT; if (!sb->s_qcop->set_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); if (!qid_valid(qid)) return -EINVAL; return sb->s_qcop->set_dqblk(sb, qid, &fdq); } static int quota_getxquota(struct super_block *sb, int type, qid_t id, void __user *addr) { struct fs_disk_quota fdq; struct kqid qid; int ret; if (!sb->s_qcop->get_dqblk) return -ENOSYS; qid = make_kqid(current_user_ns(), type, id); if (!qid_valid(qid)) return -EINVAL; ret = sb->s_qcop->get_dqblk(sb, qid, &fdq); if (!ret && copy_to_user(addr, &fdq, sizeof(fdq))) return -EFAULT; return ret; } /* Copy parameters and call proper function */ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void __user *addr, struct path *path) { int ret; if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS)) return -EINVAL; if (!sb->s_qcop) return -ENOSYS; ret = check_quotactl_permission(sb, type, cmd, id); if (ret < 0) return ret; switch (cmd) { case Q_QUOTAON: return quota_quotaon(sb, type, cmd, id, path); case Q_QUOTAOFF: if (!sb->s_qcop->quota_off) return -ENOSYS; return sb->s_qcop->quota_off(sb, type); case Q_GETFMT: return quota_getfmt(sb, type, addr); case Q_GETINFO: return quota_getinfo(sb, type, addr); case Q_SETINFO: return quota_setinfo(sb, type, addr); case Q_GETQUOTA: return quota_getquota(sb, type, id, addr); case Q_SETQUOTA: return quota_setquota(sb, type, id, addr); case Q_SYNC: if (!sb->s_qcop->quota_sync) return -ENOSYS; return sb->s_qcop->quota_sync(sb, type); case Q_XQUOTAON: case Q_XQUOTAOFF: case Q_XQUOTARM: return quota_setxstate(sb, cmd, addr); case Q_XGETQSTAT: return quota_getxstate(sb, addr); case Q_XSETQLIM: return quota_setxquota(sb, type, id, addr); case Q_XGETQUOTA: return quota_getxquota(sb, type, id, addr); case Q_XQUOTASYNC: if (sb->s_flags & MS_RDONLY) return -EROFS; /* XFS quotas are fully coherent now, making this call a noop */ return 0; default: return -EINVAL; } } #ifdef CONFIG_BLOCK /* Return 1 if 'cmd' will block on frozen filesystem */ static int quotactl_cmd_write(int cmd) { switch (cmd) { case Q_GETFMT: case Q_GETINFO: case Q_SYNC: case Q_XGETQSTAT: case Q_XGETQUOTA: case Q_XQUOTASYNC: return 0; } return 1; } #endif /* CONFIG_BLOCK */ /* * look up a superblock on which quota ops will be performed * - use the name of a block device to find the superblock thereon */ static struct super_block *quotactl_block(const char __user *special, int cmd) { #ifdef CONFIG_BLOCK struct block_device *bdev; struct super_block *sb; struct filename *tmp = getname(special); if (IS_ERR(tmp)) return ERR_CAST(tmp); bdev = lookup_bdev(tmp->name); putname(tmp); if (IS_ERR(bdev)) return ERR_CAST(bdev); if (quotactl_cmd_write(cmd)) sb = get_super_thawed(bdev); else sb = get_super(bdev); bdput(bdev); if (!sb) return ERR_PTR(-ENODEV); return sb; #else return ERR_PTR(-ENODEV); #endif } /* * This is the system call interface. This communicates with * the user-level programs. Currently this only supports diskquota * calls. Maybe we need to add the process quotas etc. in the future, * but we probably should use rlimits for that. */ SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special, qid_t, id, void __user *, addr) { uint cmds, type; struct super_block *sb = NULL; struct path path, *pathp = NULL; int ret; cmds = cmd >> SUBCMDSHIFT; type = cmd & SUBCMDMASK; /* * As a special case Q_SYNC can be called without a specific device. * It will iterate all superblocks that have quota enabled and call * the sync action on each of them. */ if (!special) { if (cmds == Q_SYNC) return quota_sync_all(type); return -ENODEV; } /* * Path for quotaon has to be resolved before grabbing superblock * because that gets s_umount sem which is also possibly needed by path * resolution (think about autofs) and thus deadlocks could arise. */ if (cmds == Q_QUOTAON) { ret = user_path_at(AT_FDCWD, addr, LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT, &path); if (ret) pathp = ERR_PTR(ret); else pathp = &path; } sb = quotactl_block(special, cmds); if (IS_ERR(sb)) { ret = PTR_ERR(sb); goto out; } ret = do_quotactl(sb, type, cmds, id, addr, pathp); drop_super(sb); out: if (pathp && !IS_ERR(pathp)) path_put(pathp); return ret; }