/* * Copyright (c) 1993 Jan-Simon Pendry * Copyright (c) 1993 Sean Eric Fagan * Copyright (c) 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * Jan-Simon Pendry and Sean Eric Fagan. * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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. * * @(#)procfs_mem.c 8.5 (Berkeley) 6/15/94 * * $FreeBSD$ */ /* * This is a lightly hacked and merged version * of sef's pread/pwrite functions */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static int procfs_rwmem __P((struct proc *curp, struct proc *p, struct uio *uio)); static int procfs_rwmem(curp, p, uio) struct proc *curp; struct proc *p; struct uio *uio; { int error; int writing; struct vmspace *vm; vm_map_t map; vm_object_t object = NULL; vm_offset_t pageno = 0; /* page number */ vm_prot_t reqprot; vm_offset_t kva; /* * if the vmspace is in the midst of being deallocated or the * process is exiting, don't try to grab anything. The page table * usage in that process can be messed up. */ vm = p->p_vmspace; if ((p->p_flag & P_WEXIT)) return EFAULT; mtx_lock(&vm_mtx); if (vm->vm_refcnt < 1) { mtx_unlock(&vm_mtx); return EFAULT; } ++vm->vm_refcnt; /* * The map we want... */ map = &vm->vm_map; writing = uio->uio_rw == UIO_WRITE; reqprot = writing ? (VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE) : VM_PROT_READ; kva = kmem_alloc_pageable(kernel_map, PAGE_SIZE); /* * Only map in one page at a time. We don't have to, but it * makes things easier. This way is trivial - right? */ do { vm_map_t tmap; vm_offset_t uva; int page_offset; /* offset into page */ vm_map_entry_t out_entry; vm_prot_t out_prot; boolean_t wired; vm_pindex_t pindex; u_int len; vm_page_t m; object = NULL; uva = (vm_offset_t) uio->uio_offset; /* * Get the page number of this segment. */ pageno = trunc_page(uva); page_offset = uva - pageno; /* * How many bytes to copy */ len = min(PAGE_SIZE - page_offset, uio->uio_resid); /* * Fault the page on behalf of the process */ error = vm_fault(map, pageno, reqprot, VM_FAULT_NORMAL); if (error) { error = EFAULT; break; } /* * Now we need to get the page. out_entry, out_prot, wired, * and single_use aren't used. One would think the vm code * would be a *bit* nicer... We use tmap because * vm_map_lookup() can change the map argument. */ tmap = map; error = vm_map_lookup(&tmap, pageno, reqprot, &out_entry, &object, &pindex, &out_prot, &wired); if (error) { error = EFAULT; /* * Make sure that there is no residue in 'object' from * an error return on vm_map_lookup. */ object = NULL; break; } m = vm_page_lookup(object, pindex); /* Allow fallback to backing objects if we are reading */ while (m == NULL && !writing && object->backing_object) { pindex += OFF_TO_IDX(object->backing_object_offset); object = object->backing_object; m = vm_page_lookup(object, pindex); } if (m == NULL) { error = EFAULT; /* * Make sure that there is no residue in 'object' from * an error return on vm_map_lookup. */ object = NULL; vm_map_lookup_done(tmap, out_entry); break; } /* * Wire the page into memory */ vm_page_wire(m); /* * We're done with tmap now. * But reference the object first, so that we won't loose * it. */ vm_object_reference(object); vm_map_lookup_done(tmap, out_entry); pmap_kenter(kva, VM_PAGE_TO_PHYS(m)); /* * Now do the i/o move. */ mtx_unlock(&vm_mtx); error = uiomove((caddr_t)(kva + page_offset), len, uio); mtx_lock(&vm_mtx); pmap_kremove(kva); /* * release the page and the object */ vm_page_unwire(m, 1); vm_object_deallocate(object); object = NULL; } while (error == 0 && uio->uio_resid > 0); if (object) vm_object_deallocate(object); kmem_free(kernel_map, kva, PAGE_SIZE); vmspace_free(vm); mtx_unlock(&vm_mtx); return (error); } /* * Copy data in and out of the target process. * We do this by mapping the process's page into * the kernel and then doing a uiomove direct * from the kernel address space. */ int procfs_domem(curp, p, pfs, uio) struct proc *curp; struct proc *p; struct pfsnode *pfs; struct uio *uio; { if (uio->uio_resid == 0) return (0); /* * XXX * We need to check for KMEM_GROUP because ps is sgid kmem; * not allowing it here causes ps to not work properly. Arguably, * this is a bug with what ps does. We only need to do this * for Pmem nodes, and only if it's reading. This is still not * good, as it may still be possible to grab illicit data if * a process somehow gets to be KMEM_GROUP. Note that this also * means that KMEM_GROUP can't change without editing procfs.h! * All in all, quite yucky. */ if (p_can(curp, p, P_CAN_DEBUG, NULL) && !(uio->uio_rw == UIO_READ && procfs_kmemaccess(curp))) return EPERM; return (procfs_rwmem(curp, p, uio)); } /* * Given process (p), find the vnode from which * its text segment is being executed. * * It would be nice to grab this information from * the VM system, however, there is no sure-fire * way of doing that. Instead, fork(), exec() and * wait() all maintain the p_textvp field in the * process proc structure which contains a held * reference to the exec'ed vnode. * * XXX - Currently, this is not not used, as the * /proc/pid/file object exposes an information leak * that shouldn't happen. Using a mount option would * make it configurable on a per-system (or, at least, * per-mount) basis; however, that's not really best. * The best way to do it, I think, would be as an * ioctl; this would restrict it to the uid running * program, or root, which seems a reasonable compromise. * However, the number of applications for this is * minimal, if it can't be seen in the filesytem space, * and doint it as an ioctl makes it somewhat less * useful due to the, well, inelegance. * */ struct vnode * procfs_findtextvp(p) struct proc *p; { return (p->p_textvp); } int procfs_kmemaccess(curp) struct proc *curp; { int i; struct ucred *cred; cred = curp->p_ucred; if (suser(curp)) return 1; /* XXX: Why isn't this done with file-perms ??? */ for (i = 0; i < cred->cr_ngroups; i++) if (cred->cr_groups[i] == KMEM_GROUP) return 1; return 0; }