/* * 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 <asm/uaccess.h> #include <linux/kernel.h> #include <linux/smp_lock.h> #include <linux/security.h> /* Check validity of quotactl */ static int check_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id) { if (type >= MAXQUOTAS) return -EINVAL; /* Is operation supported? */ if (!sb->s_qcop) return -ENOSYS; switch (cmd) { case Q_GETFMT: break; case Q_QUOTAON: if (!sb->s_qcop->quota_on) return -ENOSYS; break; case Q_QUOTAOFF: if (!sb->s_qcop->quota_off) return -ENOSYS; break; case Q_SETINFO: if (!sb->s_qcop->set_info) return -ENOSYS; break; case Q_GETINFO: if (!sb->s_qcop->get_info) return -ENOSYS; break; case Q_SETQUOTA: if (!sb->s_qcop->set_dqblk) return -ENOSYS; break; case Q_GETQUOTA: if (!sb->s_qcop->get_dqblk) return -ENOSYS; break; case Q_SYNC: if (!sb->s_qcop->quota_sync) return -ENOSYS; break; case Q_XQUOTAON: case Q_XQUOTAOFF: case Q_XQUOTARM: if (!sb->s_qcop->set_xstate) return -ENOSYS; break; case Q_XGETQSTAT: if (!sb->s_qcop->get_xstate) return -ENOSYS; break; case Q_XSETQLIM: if (!sb->s_qcop->set_xquota) return -ENOSYS; break; case Q_XGETQUOTA: if (!sb->s_qcop->get_xquota) return -ENOSYS; break; default: return -EINVAL; } /* Is quota turned on for commands which need it? */ switch (cmd) { case Q_GETFMT: case Q_GETINFO: case Q_QUOTAOFF: case Q_SETINFO: case Q_SETQUOTA: case Q_GETQUOTA: if (!sb_has_quota_enabled(sb, type)) return -ESRCH; } /* Check privileges */ if (cmd == Q_GETQUOTA || cmd == Q_XGETQUOTA) { if (((type == USRQUOTA && current->euid != id) || (type == GRPQUOTA && !in_egroup_p(id))) && !capable(CAP_SYS_ADMIN)) return -EPERM; } else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO && cmd != Q_XGETQSTAT) if (!capable(CAP_SYS_ADMIN)) return -EPERM; return security_ops->quotactl (cmd, type, id, sb); } /* Resolve device pathname to superblock */ static struct super_block *resolve_dev(const char *path) { int ret; mode_t mode; struct nameidata nd; struct block_device *bdev; struct super_block *sb; ret = user_path_walk(path, &nd); if (ret) goto out; bdev = nd.dentry->d_inode->i_bdev; mode = nd.dentry->d_inode->i_mode; path_release(&nd); ret = -ENOTBLK; if (!S_ISBLK(mode)) goto out; ret = -ENODEV; sb = get_super(bdev); if (!sb) goto out; return sb; out: return ERR_PTR(ret); } /* Copy parameters and call proper function */ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, caddr_t addr) { int ret; switch (cmd) { case Q_QUOTAON: { char *pathname; if (IS_ERR(pathname = getname(addr))) return PTR_ERR(pathname); ret = sb->s_qcop->quota_on(sb, type, id, pathname); putname(pathname); return ret; } case Q_QUOTAOFF: return sb->s_qcop->quota_off(sb, type); case Q_GETFMT: { __u32 fmt; fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id; if (copy_to_user(addr, &fmt, sizeof(fmt))) return -EFAULT; return 0; } case Q_GETINFO: { struct if_dqinfo info; if ((ret = sb->s_qcop->get_info(sb, type, &info))) return ret; if (copy_to_user(addr, &info, sizeof(info))) return -EFAULT; return 0; } case Q_SETINFO: { struct if_dqinfo info; if (copy_from_user(&info, addr, sizeof(info))) return -EFAULT; return sb->s_qcop->set_info(sb, type, &info); } case Q_GETQUOTA: { struct if_dqblk idq; if ((ret = sb->s_qcop->get_dqblk(sb, type, id, &idq))) return ret; if (copy_to_user(addr, &idq, sizeof(idq))) return -EFAULT; return 0; } case Q_SETQUOTA: { struct if_dqblk idq; if (copy_from_user(&idq, addr, sizeof(idq))) return -EFAULT; return sb->s_qcop->set_dqblk(sb, type, id, &idq); } case Q_SYNC: return sb->s_qcop->quota_sync(sb, type); case Q_XQUOTAON: case Q_XQUOTAOFF: case Q_XQUOTARM: { __u32 flags; if (copy_from_user(&flags, addr, sizeof(flags))) return -EFAULT; return sb->s_qcop->set_xstate(sb, flags, cmd); } case Q_XGETQSTAT: { struct fs_quota_stat fqs; if ((ret = sb->s_qcop->get_xstate(sb, &fqs))) return ret; if (copy_to_user(addr, &fqs, sizeof(fqs))) return -EFAULT; return 0; } case Q_XSETQLIM: { struct fs_disk_quota fdq; if (copy_from_user(&fdq, addr, sizeof(fdq))) return -EFAULT; return sb->s_qcop->set_xquota(sb, type, id, &fdq); } case Q_XGETQUOTA: { struct fs_disk_quota fdq; if ((ret = sb->s_qcop->get_xquota(sb, type, id, &fdq))) return ret; if (copy_to_user(addr, &fdq, sizeof(fdq))) return -EFAULT; return 0; } /* We never reach here unless validity check is broken */ default: BUG(); } return 0; } /* * 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. */ asmlinkage long sys_quotactl(unsigned int cmd, const char *special, qid_t id, caddr_t addr) { uint cmds, type; struct super_block *sb = NULL; int ret = -EINVAL; lock_kernel(); cmds = cmd >> SUBCMDSHIFT; type = cmd & SUBCMDMASK; if (IS_ERR(sb = resolve_dev(special))) { ret = PTR_ERR(sb); sb = NULL; goto out; } if ((ret = check_quotactl_valid(sb, type, cmds, id)) < 0) goto out; ret = do_quotactl(sb, type, cmds, id, addr); out: if (sb) drop_super(sb); unlock_kernel(); return ret; }