/*- * Copyright (c) 1988 University of Utah. * Copyright (c) 1982, 1986, 1990 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department, and code derived from software contributed to * Berkeley by William Jolitz. * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * 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. * * from: Utah $Hdr: mem.c 1.13 89/10/08$ * from: @(#)mem.c 7.2 (Berkeley) 5/9/91 * $FreeBSD: src/sys/i386/i386/mem.c,v 1.79.2.9 2003/01/04 22:58:01 njl Exp $ */ /* * Memory special file */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static d_open_t mmopen; static d_close_t mmclose; static d_read_t mmread; static d_write_t mmwrite; static d_ioctl_t mmioctl; #if 0 static d_mmap_t memmmap; #endif static d_kqfilter_t mmkqfilter; static int memuksmap(cdev_t dev, vm_page_t fake); #define CDEV_MAJOR 2 static struct dev_ops mem_ops = { { "mem", 0, D_MPSAFE }, .d_open = mmopen, .d_close = mmclose, .d_read = mmread, .d_write = mmwrite, .d_ioctl = mmioctl, .d_kqfilter = mmkqfilter, #if 0 .d_mmap = memmmap, #endif .d_uksmap = memuksmap }; static int rand_bolt; static caddr_t zbuf; static cdev_t zerodev = NULL; MALLOC_DEFINE(M_MEMDESC, "memdesc", "memory range descriptors"); static int mem_ioctl (cdev_t, u_long, caddr_t, int, struct ucred *); static int random_ioctl (cdev_t, u_long, caddr_t, int, struct ucred *); struct mem_range_softc mem_range_softc; static int seedenable; SYSCTL_INT(_kern, OID_AUTO, seedenable, CTLFLAG_RW, &seedenable, 0, ""); static int mmopen(struct dev_open_args *ap) { cdev_t dev = ap->a_head.a_dev; int error; switch (minor(dev)) { case 0: case 1: /* * /dev/mem and /dev/kmem */ if (ap->a_oflags & FWRITE) { if (securelevel > 0 || kernel_mem_readonly) return (EPERM); } error = 0; break; case 6: /* * /dev/kpmap can only be opened for reading. */ if (ap->a_oflags & FWRITE) return (EPERM); error = 0; break; case 14: error = priv_check_cred(ap->a_cred, PRIV_ROOT, 0); if (error != 0) break; if (securelevel > 0 || kernel_mem_readonly) { error = EPERM; break; } error = cpu_set_iopl(); break; default: error = 0; break; } return (error); } static int mmclose(struct dev_close_args *ap) { cdev_t dev = ap->a_head.a_dev; int error; switch (minor(dev)) { case 14: error = cpu_clr_iopl(); break; default: error = 0; break; } return (error); } static int mmrw(cdev_t dev, struct uio *uio, int flags) { int o; u_int c; u_int poolsize; u_long v; struct iovec *iov; int error = 0; caddr_t buf = NULL; while (uio->uio_resid > 0 && error == 0) { iov = uio->uio_iov; if (iov->iov_len == 0) { uio->uio_iov++; uio->uio_iovcnt--; if (uio->uio_iovcnt < 0) panic("mmrw"); continue; } switch (minor(dev)) { case 0: /* * minor device 0 is physical memory, /dev/mem */ v = uio->uio_offset; v &= ~(long)PAGE_MASK; pmap_kenter((vm_offset_t)ptvmmap, v); o = (int)uio->uio_offset & PAGE_MASK; c = (u_int)(PAGE_SIZE - ((uintptr_t)iov->iov_base & PAGE_MASK)); c = min(c, (u_int)(PAGE_SIZE - o)); c = min(c, (u_int)iov->iov_len); error = uiomove((caddr_t)&ptvmmap[o], (int)c, uio); pmap_kremove((vm_offset_t)ptvmmap); continue; case 1: { /* * minor device 1 is kernel memory, /dev/kmem */ vm_offset_t saddr, eaddr; int prot; c = iov->iov_len; /* * Make sure that all of the pages are currently * resident so that we don't create any zero-fill * pages. */ saddr = trunc_page(uio->uio_offset); eaddr = round_page(uio->uio_offset + c); if (saddr > eaddr) return EFAULT; /* * Make sure the kernel addresses are mapped. * platform_direct_mapped() can be used to bypass * default mapping via the page table (virtual kernels * contain a lot of out-of-band data). */ prot = VM_PROT_READ; if (uio->uio_rw != UIO_READ) prot |= VM_PROT_WRITE; error = kvm_access_check(saddr, eaddr, prot); if (error) return (error); error = uiomove((caddr_t)(vm_offset_t)uio->uio_offset, (int)c, uio); continue; } case 2: /* * minor device 2 (/dev/null) is EOF/RATHOLE */ if (uio->uio_rw == UIO_READ) return (0); c = iov->iov_len; break; case 3: /* * minor device 3 (/dev/random) is source of filth * on read, seeder on write */ if (buf == NULL) buf = kmalloc(PAGE_SIZE, M_TEMP, M_WAITOK); c = min(iov->iov_len, PAGE_SIZE); if (uio->uio_rw == UIO_WRITE) { error = uiomove(buf, (int)c, uio); if (error == 0 && seedenable && securelevel <= 0) { error = add_buffer_randomness_src(buf, c, RAND_SRC_SEEDING); } else if (error == 0) { error = EPERM; } } else { poolsize = read_random(buf, c); if (poolsize == 0) { if (buf) kfree(buf, M_TEMP); if ((flags & IO_NDELAY) != 0) return (EWOULDBLOCK); return (0); } c = min(c, poolsize); error = uiomove(buf, (int)c, uio); } continue; case 4: /* * minor device 4 (/dev/urandom) is source of muck * on read, writes are disallowed. */ c = min(iov->iov_len, PAGE_SIZE); if (uio->uio_rw == UIO_WRITE) { error = EPERM; break; } if (CURSIG(curthread->td_lwp) != 0) { /* * Use tsleep() to get the error code right. * It should return immediately. */ error = tsleep(&rand_bolt, PCATCH, "urand", 1); if (error != 0 && error != EWOULDBLOCK) continue; } if (buf == NULL) buf = kmalloc(PAGE_SIZE, M_TEMP, M_WAITOK); poolsize = read_random_unlimited(buf, c); c = min(c, poolsize); error = uiomove(buf, (int)c, uio); continue; /* case 5: read/write not supported, mmap only */ /* case 6: read/write not supported, mmap only */ case 12: /* * minor device 12 (/dev/zero) is source of nulls * on read, write are disallowed. */ if (uio->uio_rw == UIO_WRITE) { c = iov->iov_len; break; } if (zbuf == NULL) { zbuf = (caddr_t)kmalloc(PAGE_SIZE, M_TEMP, M_WAITOK | M_ZERO); } c = min(iov->iov_len, PAGE_SIZE); error = uiomove(zbuf, (int)c, uio); continue; default: return (ENODEV); } if (error) break; iov->iov_base = (char *)iov->iov_base + c; iov->iov_len -= c; uio->uio_offset += c; uio->uio_resid -= c; } if (buf) kfree(buf, M_TEMP); return (error); } static int mmread(struct dev_read_args *ap) { return(mmrw(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); } static int mmwrite(struct dev_write_args *ap) { return(mmrw(ap->a_head.a_dev, ap->a_uio, ap->a_ioflag)); } /*******************************************************\ * allow user processes to MMAP some memory sections * * instead of going through read/write * \*******************************************************/ static int user_kernel_mapping(int num, vm_ooffset_t offset, vm_ooffset_t *resultp); #if 0 static int memmmap(struct dev_mmap_args *ap) { cdev_t dev = ap->a_head.a_dev; vm_ooffset_t result; int error; switch (minor(dev)) { case 0: /* * minor device 0 is physical memory */ ap->a_result = atop(ap->a_offset); error = 0; break; case 1: /* * minor device 1 is kernel memory */ ap->a_result = atop(vtophys(ap->a_offset)); error = 0; break; case 5: case 6: /* * minor device 5 is /dev/upmap (see sys/upmap.h) * minor device 6 is /dev/kpmap (see sys/upmap.h) */ result = 0; error = user_kernel_mapping(minor(dev), ap->a_offset, &result); ap->a_result = atop(result); break; default: error = EINVAL; break; } return error; } #endif static int memuksmap(cdev_t dev, vm_page_t fake) { vm_ooffset_t result; int error; switch (minor(dev)) { case 0: /* * minor device 0 is physical memory */ fake->phys_addr = ptoa(fake->pindex); error = 0; break; case 1: /* * minor device 1 is kernel memory */ fake->phys_addr = vtophys(ptoa(fake->pindex)); error = 0; break; case 5: case 6: /* * minor device 5 is /dev/upmap (see sys/upmap.h) * minor device 6 is /dev/kpmap (see sys/upmap.h) */ result = 0; error = user_kernel_mapping(minor(dev), ptoa(fake->pindex), &result); fake->phys_addr = result; break; default: error = EINVAL; break; } return error; } static int mmioctl(struct dev_ioctl_args *ap) { cdev_t dev = ap->a_head.a_dev; int error; get_mplock(); switch (minor(dev)) { case 0: error = mem_ioctl(dev, ap->a_cmd, ap->a_data, ap->a_fflag, ap->a_cred); break; case 3: case 4: error = random_ioctl(dev, ap->a_cmd, ap->a_data, ap->a_fflag, ap->a_cred); break; default: error = ENODEV; break; } rel_mplock(); return (error); } /* * Operations for changing memory attributes. * * This is basically just an ioctl shim for mem_range_attr_get * and mem_range_attr_set. */ static int mem_ioctl(cdev_t dev, u_long cmd, caddr_t data, int flags, struct ucred *cred) { int nd, error = 0; struct mem_range_op *mo = (struct mem_range_op *)data; struct mem_range_desc *md; /* is this for us? */ if ((cmd != MEMRANGE_GET) && (cmd != MEMRANGE_SET)) return (ENOTTY); /* any chance we can handle this? */ if (mem_range_softc.mr_op == NULL) return (EOPNOTSUPP); /* do we have any descriptors? */ if (mem_range_softc.mr_ndesc == 0) return (ENXIO); switch (cmd) { case MEMRANGE_GET: nd = imin(mo->mo_arg[0], mem_range_softc.mr_ndesc); if (nd > 0) { md = (struct mem_range_desc *) kmalloc(nd * sizeof(struct mem_range_desc), M_MEMDESC, M_WAITOK); error = mem_range_attr_get(md, &nd); if (!error) error = copyout(md, mo->mo_desc, nd * sizeof(struct mem_range_desc)); kfree(md, M_MEMDESC); } else { nd = mem_range_softc.mr_ndesc; } mo->mo_arg[0] = nd; break; case MEMRANGE_SET: md = (struct mem_range_desc *)kmalloc(sizeof(struct mem_range_desc), M_MEMDESC, M_WAITOK); error = copyin(mo->mo_desc, md, sizeof(struct mem_range_desc)); /* clamp description string */ md->mr_owner[sizeof(md->mr_owner) - 1] = 0; if (error == 0) error = mem_range_attr_set(md, &mo->mo_arg[0]); kfree(md, M_MEMDESC); break; } return (error); } /* * Implementation-neutral, kernel-callable functions for manipulating * memory range attributes. */ int mem_range_attr_get(struct mem_range_desc *mrd, int *arg) { /* can we handle this? */ if (mem_range_softc.mr_op == NULL) return (EOPNOTSUPP); if (*arg == 0) { *arg = mem_range_softc.mr_ndesc; } else { bcopy(mem_range_softc.mr_desc, mrd, (*arg) * sizeof(struct mem_range_desc)); } return (0); } int mem_range_attr_set(struct mem_range_desc *mrd, int *arg) { /* can we handle this? */ if (mem_range_softc.mr_op == NULL) return (EOPNOTSUPP); return (mem_range_softc.mr_op->set(&mem_range_softc, mrd, arg)); } void mem_range_AP_init(void) { if (mem_range_softc.mr_op && mem_range_softc.mr_op->initAP) mem_range_softc.mr_op->initAP(&mem_range_softc); } static int random_ioctl(cdev_t dev, u_long cmd, caddr_t data, int flags, struct ucred *cred) { int error; int intr; /* * Even inspecting the state is privileged, since it gives a hint * about how easily the randomness might be guessed. */ error = 0; switch (cmd) { /* Really handled in upper layer */ case FIOASYNC: break; case MEM_SETIRQ: intr = *(int16_t *)data; if ((error = priv_check_cred(cred, PRIV_ROOT, 0)) != 0) break; if (intr < 0 || intr >= MAX_INTS) return (EINVAL); register_randintr(intr); break; case MEM_CLEARIRQ: intr = *(int16_t *)data; if ((error = priv_check_cred(cred, PRIV_ROOT, 0)) != 0) break; if (intr < 0 || intr >= MAX_INTS) return (EINVAL); unregister_randintr(intr); break; case MEM_RETURNIRQ: error = ENOTSUP; break; case MEM_FINDIRQ: intr = *(int16_t *)data; if ((error = priv_check_cred(cred, PRIV_ROOT, 0)) != 0) break; if (intr < 0 || intr >= MAX_INTS) return (EINVAL); intr = next_registered_randintr(intr); if (intr == MAX_INTS) return (ENOENT); *(u_int16_t *)data = intr; break; default: error = ENOTSUP; break; } return (error); } static int mm_filter_read(struct knote *kn, long hint) { return (1); } static int mm_filter_write(struct knote *kn, long hint) { return (1); } static void dummy_filter_detach(struct knote *kn) {} /* Implemented in kern_nrandom.c */ static struct filterops random_read_filtops = { FILTEROP_ISFD|FILTEROP_MPSAFE, NULL, dummy_filter_detach, random_filter_read }; static struct filterops mm_read_filtops = { FILTEROP_ISFD|FILTEROP_MPSAFE, NULL, dummy_filter_detach, mm_filter_read }; static struct filterops mm_write_filtops = { FILTEROP_ISFD|FILTEROP_MPSAFE, NULL, dummy_filter_detach, mm_filter_write }; static int mmkqfilter(struct dev_kqfilter_args *ap) { struct knote *kn = ap->a_kn; cdev_t dev = ap->a_head.a_dev; ap->a_result = 0; switch (kn->kn_filter) { case EVFILT_READ: switch (minor(dev)) { case 3: kn->kn_fop = &random_read_filtops; break; default: kn->kn_fop = &mm_read_filtops; break; } break; case EVFILT_WRITE: kn->kn_fop = &mm_write_filtops; break; default: ap->a_result = EOPNOTSUPP; return (0); } return (0); } int iszerodev(cdev_t dev) { return (zerodev == dev); } /* * /dev/upmap and /dev/kpmap. */ static int user_kernel_mapping(int num, vm_ooffset_t offset, vm_ooffset_t *resultp) { struct proc *p; int error; int invfork; if ((p = curproc) == NULL) return (EINVAL); /* * If this is a child currently in vfork the pmap is shared with * the parent! We need to actually set-up the parent's p_upmap, * not the child's, and we need to set the invfork flag. Userland * will probably adjust its static state so it must be consistent * with the parent or userland will be really badly confused. * * (this situation can happen when user code in vfork() calls * libc's getpid() or some other function which then decides * it wants the upmap). */ if (p->p_flags & P_PPWAIT) { p = p->p_pptr; if (p == NULL) return (EINVAL); invfork = 1; } else { invfork = 0; } error = EINVAL; switch(num) { case 5: /* * /dev/upmap - maps RW per-process shared user-kernel area. */ if (p->p_upmap == NULL) proc_usermap(p, invfork); else if (invfork) p->p_upmap->invfork = invfork; if (p->p_upmap && offset < roundup2(sizeof(*p->p_upmap), PAGE_SIZE)) { /* only good for current process */ *resultp = pmap_kextract((vm_offset_t)p->p_upmap + offset); error = 0; } break; case 6: /* * /dev/kpmap - maps RO shared kernel global page */ if (kpmap && offset < roundup2(sizeof(*kpmap), PAGE_SIZE)) { *resultp = pmap_kextract((vm_offset_t)kpmap + offset); error = 0; } break; default: break; } return error; } static void mem_drvinit(void *unused) { /* Initialise memory range handling */ if (mem_range_softc.mr_op != NULL) mem_range_softc.mr_op->init(&mem_range_softc); make_dev(&mem_ops, 0, UID_ROOT, GID_KMEM, 0640, "mem"); make_dev(&mem_ops, 1, UID_ROOT, GID_KMEM, 0640, "kmem"); make_dev(&mem_ops, 2, UID_ROOT, GID_WHEEL, 0666, "null"); make_dev(&mem_ops, 3, UID_ROOT, GID_WHEEL, 0644, "random"); make_dev(&mem_ops, 4, UID_ROOT, GID_WHEEL, 0644, "urandom"); make_dev(&mem_ops, 5, UID_ROOT, GID_WHEEL, 0666, "upmap"); make_dev(&mem_ops, 6, UID_ROOT, GID_WHEEL, 0444, "kpmap"); zerodev = make_dev(&mem_ops, 12, UID_ROOT, GID_WHEEL, 0666, "zero"); make_dev(&mem_ops, 14, UID_ROOT, GID_WHEEL, 0600, "io"); } SYSINIT(memdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR,mem_drvinit,NULL)