1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2009 Robert N. M. Watson 5 * Copyright (c) 2009 Bjoern A. Zeeb <bz@FreeBSD.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 35 #define _WANT_PRISON 36 #define _WANT_UCRED 37 #define _WANT_VNET 38 39 #include <sys/_lock.h> 40 #include <sys/_mutex.h> 41 #include <sys/_task.h> 42 #include <sys/jail.h> 43 #include <sys/proc.h> 44 #include <sys/types.h> 45 46 #include <stdbool.h> 47 #include <net/vnet.h> 48 49 #include <kvm.h> 50 #include <limits.h> 51 #include <stdlib.h> 52 #include <unistd.h> 53 54 #include "kvm_private.h" 55 56 /* 57 * Set up libkvm to handle virtual network stack symbols by selecting a 58 * starting pid. 59 */ 60 int 61 _kvm_vnet_selectpid(kvm_t *kd, pid_t pid) 62 { 63 struct proc proc; 64 struct ucred cred; 65 struct prison prison; 66 struct vnet vnet; 67 struct kvm_nlist nl[] = { 68 /* 69 * Note: kvm_nlist strips the first '_' so add an extra one 70 * here to __{start,stop}_set_vnet. 71 */ 72 #define NLIST_START_VNET 0 73 { .n_name = "___start_" VNET_SETNAME }, 74 #define NLIST_STOP_VNET 1 75 { .n_name = "___stop_" VNET_SETNAME }, 76 #define NLIST_VNET_HEAD 2 77 { .n_name = "vnet_head" }, 78 #define NLIST_ALLPROC 3 79 { .n_name = "allproc" }, 80 #define NLIST_DUMPTID 4 81 { .n_name = "dumptid" }, 82 #define NLIST_PROC0 5 83 { .n_name = "proc0" }, 84 { .n_name = NULL }, 85 }; 86 uintptr_t procp, credp; 87 #define VMCORE_VNET_OF_PROC0 88 #ifndef VMCORE_VNET_OF_PROC0 89 struct thread td; 90 uintptr_t tdp; 91 #endif 92 lwpid_t dumptid; 93 94 /* 95 * XXX: This only works for native kernels for now. 96 */ 97 if (!kvm_native(kd)) 98 return (-1); 99 100 /* 101 * Locate and cache locations of important symbols 102 * using the internal version of _kvm_nlist, turning 103 * off initialization to avoid recursion in case of 104 * unresolveable symbols. 105 */ 106 if (_kvm_nlist(kd, nl, 0) != 0) { 107 /* 108 * XXX-BZ: ___start_/___stop_VNET_SETNAME may fail. 109 * For now do not report an error here as we are called 110 * internally and in `void context' until we merge the 111 * functionality to optionally activate this into programs. 112 * By that time we can properly fail and let the callers 113 * handle the error. 114 */ 115 /* _kvm_err(kd, kd->program, "%s: no namelist", __func__); */ 116 return (-1); 117 } 118 119 /* 120 * Auto-detect if this is a crashdump by reading dumptid. 121 */ 122 dumptid = 0; 123 if (nl[NLIST_DUMPTID].n_value) { 124 if (kvm_read(kd, nl[NLIST_DUMPTID].n_value, &dumptid, 125 sizeof(dumptid)) != sizeof(dumptid)) { 126 _kvm_err(kd, kd->program, "%s: dumptid", __func__); 127 return (-1); 128 } 129 } 130 131 /* 132 * First, find the process for this pid. If we are working on a 133 * dump, either locate the thread dumptid is referring to or proc0. 134 * Based on either, take the address of the ucred. 135 */ 136 credp = 0; 137 138 procp = nl[NLIST_ALLPROC].n_value; 139 #ifdef VMCORE_VNET_OF_PROC0 140 if (dumptid > 0) { 141 procp = nl[NLIST_PROC0].n_value; 142 pid = 0; 143 } 144 #endif 145 while (procp != 0) { 146 if (kvm_read(kd, procp, &proc, sizeof(proc)) != sizeof(proc)) { 147 _kvm_err(kd, kd->program, "%s: proc", __func__); 148 return (-1); 149 } 150 #ifndef VMCORE_VNET_OF_PROC0 151 if (dumptid > 0) { 152 tdp = (uintptr_t)TAILQ_FIRST(&proc.p_threads); 153 while (tdp != 0) { 154 if (kvm_read(kd, tdp, &td, sizeof(td)) != 155 sizeof(td)) { 156 _kvm_err(kd, kd->program, "%s: thread", 157 __func__); 158 return (-1); 159 } 160 if (td.td_tid == dumptid) { 161 credp = (uintptr_t)td.td_ucred; 162 break; 163 } 164 tdp = (uintptr_t)TAILQ_NEXT(&td, td_plist); 165 } 166 } else 167 #endif 168 if (proc.p_pid == pid) 169 credp = (uintptr_t)proc.p_ucred; 170 if (credp != 0) 171 break; 172 procp = (uintptr_t)LIST_NEXT(&proc, p_list); 173 } 174 if (credp == 0) { 175 _kvm_err(kd, kd->program, "%s: pid/tid not found", __func__); 176 return (-1); 177 } 178 if (kvm_read(kd, (uintptr_t)credp, &cred, sizeof(cred)) != 179 sizeof(cred)) { 180 _kvm_err(kd, kd->program, "%s: cred", __func__); 181 return (-1); 182 } 183 if (cred.cr_prison == NULL) { 184 _kvm_err(kd, kd->program, "%s: no jail", __func__); 185 return (-1); 186 } 187 if (kvm_read(kd, (uintptr_t)cred.cr_prison, &prison, sizeof(prison)) != 188 sizeof(prison)) { 189 _kvm_err(kd, kd->program, "%s: prison", __func__); 190 return (-1); 191 } 192 if (prison.pr_vnet == NULL) { 193 _kvm_err(kd, kd->program, "%s: no vnet", __func__); 194 return (-1); 195 } 196 if (kvm_read(kd, (uintptr_t)prison.pr_vnet, &vnet, sizeof(vnet)) != 197 sizeof(vnet)) { 198 _kvm_err(kd, kd->program, "%s: vnet", __func__); 199 return (-1); 200 } 201 if (vnet.vnet_magic_n != VNET_MAGIC_N) { 202 _kvm_err(kd, kd->program, "%s: invalid vnet magic#", __func__); 203 return (-1); 204 } 205 kd->vnet_initialized = 1; 206 kd->vnet_start = nl[NLIST_START_VNET].n_value; 207 kd->vnet_stop = nl[NLIST_STOP_VNET].n_value; 208 kd->vnet_current = (uintptr_t)prison.pr_vnet; 209 kd->vnet_base = vnet.vnet_data_base; 210 return (0); 211 } 212 213 /* 214 * Check whether the vnet module has been initialized successfully 215 * or not, initialize it if permitted. 216 */ 217 int 218 _kvm_vnet_initialized(kvm_t *kd, int intialize) 219 { 220 221 if (kd->vnet_initialized || !intialize) 222 return (kd->vnet_initialized); 223 224 (void) _kvm_vnet_selectpid(kd, getpid()); 225 226 return (kd->vnet_initialized); 227 } 228 229 /* 230 * Check whether the value is within the vnet symbol range and 231 * only if so adjust the offset relative to the current base. 232 */ 233 kvaddr_t 234 _kvm_vnet_validaddr(kvm_t *kd, kvaddr_t value) 235 { 236 237 if (value == 0) 238 return (value); 239 240 if (!kd->vnet_initialized) 241 return (value); 242 243 if (value < kd->vnet_start || value >= kd->vnet_stop) 244 return (value); 245 246 return (kd->vnet_base + value); 247 } 248