1 /* 2 * Copyright (c) 1993 Jan-Simon Pendry 3 * Copyright (c) 1993 Sean Eric Fagan 4 * Copyright (c) 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Jan-Simon Pendry and Sean Eric Fagan. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)procfs_mem.c 8.5 (Berkeley) 6/15/94 35 * 36 * $FreeBSD: src/sys/miscfs/procfs/procfs_mem.c,v 1.46.2.3 2002/01/22 17:22:59 nectar Exp $ 37 */ 38 39 /* 40 * This is a lightly hacked and merged version 41 * of sef's pread/pwrite functions 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/priv.h> 48 #include <sys/vnode.h> 49 #include <vfs/procfs/procfs.h> 50 #include <vm/vm.h> 51 #include <vm/vm_param.h> 52 #include <sys/lock.h> 53 #include <vm/pmap.h> 54 #include <vm/vm_extern.h> 55 #include <vm/vm_map.h> 56 #include <vm/vm_kern.h> 57 #include <vm/vm_object.h> 58 #include <vm/vm_page.h> 59 #include <sys/user.h> 60 #include <sys/ptrace.h> 61 62 #include <machine/vmm.h> 63 64 static int procfs_rwmem (struct proc *curp, 65 struct proc *p, struct uio *uio); 66 67 /* 68 * p->p_token is held on entry. 69 */ 70 static int 71 procfs_rwmem(struct proc *curp, struct proc *p, struct uio *uio) 72 { 73 int error; 74 int writing; 75 struct vmspace *vm; 76 vm_map_t map; 77 vm_offset_t pageno = 0; /* page number */ 78 vm_prot_t reqprot; 79 vm_offset_t kva; 80 81 /* 82 * if the vmspace is in the midst of being allocated or deallocated, 83 * or the process is exiting, don't try to grab anything. The 84 * page table usage in that process may be messed up. 85 */ 86 vm = p->p_vmspace; 87 if (p->p_stat == SIDL || p->p_stat == SZOMB) 88 return EFAULT; 89 if ((p->p_flags & (P_WEXIT | P_INEXEC)) || vmspace_getrefs(vm) < 0) 90 return EFAULT; 91 92 /* 93 * The map we want... 94 */ 95 vmspace_hold(vm); 96 map = &vm->vm_map; 97 98 writing = (uio->uio_rw == UIO_WRITE); 99 reqprot = VM_PROT_READ; 100 if (writing) 101 reqprot |= VM_PROT_WRITE | VM_PROT_OVERRIDE_WRITE; 102 103 kva = kmem_alloc_pageable(&kernel_map, PAGE_SIZE, VM_SUBSYS_PROC); 104 105 /* 106 * Only map in one page at a time. We don't have to, but it 107 * makes things easier. This way is trivial - right? 108 */ 109 do { 110 vm_offset_t uva; 111 vm_offset_t page_offset; /* offset into page */ 112 size_t len; 113 vm_page_t m; 114 int busy; 115 116 uva = (vm_offset_t) uio->uio_offset; 117 118 /* 119 * Get the page number of this segment. 120 */ 121 pageno = trunc_page(uva); 122 page_offset = uva - pageno; 123 124 /* 125 * If the target process is running in VMM mode 126 * translate the address into a GPA (Guest Physical 127 * Address) via the EPT before doing the lookup. 128 */ 129 if (p->p_vmm) { 130 register_t gpa; 131 vmm_vm_get_gpa(p, &gpa, (register_t) pageno); 132 pageno = (vm_offset_t)gpa; 133 } 134 135 /* 136 * How many bytes to copy 137 */ 138 len = szmin(PAGE_SIZE - page_offset, uio->uio_resid); 139 140 /* 141 * Fault the page on behalf of the process 142 * 143 * XXX busied page on write fault can deadlock against our 144 * uiomove. 145 */ 146 m = vm_fault_page(map, pageno, reqprot, 147 VM_FAULT_NORMAL, 148 &error, &busy); 149 if (error) { 150 KKASSERT(m == NULL); 151 error = EFAULT; 152 break; 153 } 154 155 /* 156 * Cleanup pmap then create a temporary KVA mapping and 157 * do the I/O. We can switch between cpus so don't bother 158 * synchronizing across all cores. 159 */ 160 pmap_kenter_quick(kva, VM_PAGE_TO_PHYS(m)); 161 error = uiomove((caddr_t)(kva + page_offset), len, uio); 162 pmap_kremove_quick(kva); 163 164 /* 165 * Release the page and we are done 166 */ 167 if (busy) 168 vm_page_wakeup(m); 169 else 170 vm_page_unhold(m); 171 } while (error == 0 && uio->uio_resid > 0); 172 173 vmspace_drop(vm); 174 kmem_free(&kernel_map, kva, PAGE_SIZE); 175 176 return (error); 177 } 178 179 /* 180 * Copy data in and out of the target process. 181 * We do this by mapping the process's page into 182 * the kernel and then doing a uiomove direct 183 * from the kernel address space. 184 * 185 * lp->lwp_proc->p_token is held on entry. 186 */ 187 int 188 procfs_domem(struct proc *curp, struct lwp *lp, struct pfsnode *pfs, 189 struct uio *uio) 190 { 191 struct proc *p = lp->lwp_proc; 192 int error; 193 194 if (uio->uio_resid == 0) 195 return (0); 196 197 if ((p->p_flags & P_INEXEC) != 0) { 198 /* 199 * Can't trace a process that's currently exec'ing. 200 */ 201 error = EAGAIN; 202 } else if (!CHECKIO(curp, p) || p_trespass(curp->p_ucred, p->p_ucred)) { 203 /* 204 * Can't trace processes outside our jail 205 */ 206 error = EPERM; 207 } else { 208 error = procfs_rwmem(curp, p, uio); 209 } 210 return(error); 211 } 212 213 /* 214 * Given process (p), find the vnode from which 215 * its text segment is being executed. 216 * 217 * It would be nice to grab this information from 218 * the VM system, however, there is no sure-fire 219 * way of doing that. Instead, fork(), exec() and 220 * wait() all maintain the p_textvp field in the 221 * process proc structure which contains a held 222 * reference to the exec'ed vnode. 223 * 224 * XXX - Currently, this is not not used, as the 225 * /proc/pid/file object exposes an information leak 226 * that shouldn't happen. Using a mount option would 227 * make it configurable on a per-system (or, at least, 228 * per-mount) basis; however, that's not really best. 229 * The best way to do it, I think, would be as an 230 * ioctl; this would restrict it to the uid running 231 * program, or root, which seems a reasonable compromise. 232 * However, the number of applications for this is 233 * minimal, if it can't be seen in the filesytem space, 234 * and doint it as an ioctl makes it somewhat less 235 * useful due to the, well, inelegance. 236 * 237 */ 238 struct vnode * 239 procfs_findtextvp(struct proc *p) 240 { 241 return (p->p_textvp); 242 } 243