1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/security/nss/lib/freebl/shvfy.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,508 @@
1.4 +
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifdef FREEBL_NO_DEPEND
1.10 +#include "stubs.h"
1.11 +#endif
1.12 +
1.13 +#include "shsign.h"
1.14 +#include "prlink.h"
1.15 +#include "prio.h"
1.16 +#include "blapi.h"
1.17 +#include "seccomon.h"
1.18 +#include "stdio.h"
1.19 +#include "prmem.h"
1.20 +#include "hasht.h"
1.21 +#include "pqg.h"
1.22 +
1.23 +/*
1.24 + * Most modern version of Linux support a speed optimization scheme where an
1.25 + * application called prelink modifies programs and shared libraries to quickly
1.26 + * load if they fit into an already designed address space. In short, prelink
1.27 + * scans the list of programs and libraries on your system, assigns them a
1.28 + * predefined space in the the address space, then provides the fixups to the
1.29 + * library.
1.30 +
1.31 + * The modification of the shared library is correctly detected by the freebl
1.32 + * FIPS checksum scheme where we check a signed hash of the library against the
1.33 + * library itself.
1.34 + *
1.35 + * The prelink command itself can reverse the process of modification and
1.36 + * output the prestine shared library as it was before prelink made it's
1.37 + * changes. If FREEBL_USE_PRELINK is set Freebl uses prelink to output the
1.38 + * original copy of the shared library before prelink modified it.
1.39 + */
1.40 +#ifdef FREEBL_USE_PRELINK
1.41 +#ifndef FREELB_PRELINK_COMMAND
1.42 +#define FREEBL_PRELINK_COMMAND "/usr/sbin/prelink -u -o -"
1.43 +#endif
1.44 +#include "private/pprio.h"
1.45 +
1.46 +#include <stdlib.h>
1.47 +#include <unistd.h>
1.48 +#include <fcntl.h>
1.49 +#include <sys/wait.h>
1.50 +#include <sys/stat.h>
1.51 +
1.52 +/*
1.53 + * This function returns an NSPR PRFileDesc * which the caller can read to
1.54 + * obtain the prestine value of the shared library, before any OS related
1.55 + * changes to it (usually address fixups).
1.56 + *
1.57 + * If prelink is installed, this
1.58 + * file descriptor is a pipe connecting the output of
1.59 + * /usr/sbin/prelink -u -o - {Library}
1.60 + * and *pid returns the process id of the prelink child.
1.61 + *
1.62 + * If prelink is not installed, it returns a normal readonly handle to the
1.63 + * library itself and *pid is set to '0'.
1.64 + */
1.65 +PRFileDesc *
1.66 +bl_OpenUnPrelink(const char *shName, int *pid)
1.67 +{
1.68 + char *command= strdup(FREEBL_PRELINK_COMMAND);
1.69 + char *argString = NULL;
1.70 + char **argv = NULL;
1.71 + char *shNameArg = NULL;
1.72 + char *cp;
1.73 + pid_t child;
1.74 + int argc = 0, argNext = 0;
1.75 + struct stat statBuf;
1.76 + int pipefd[2] = {-1,-1};
1.77 + int ret;
1.78 +
1.79 + *pid = 0;
1.80 +
1.81 + /* make sure the prelink command exists first. If not, fall back to
1.82 + * just reading the file */
1.83 + for (cp = command; *cp ; cp++) {
1.84 + if (*cp == ' ') {
1.85 + *cp++ = 0;
1.86 + argString = cp;
1.87 + break;
1.88 + }
1.89 + }
1.90 + memset (&statBuf, 0, sizeof(statBuf));
1.91 + /* stat the file, follow the link */
1.92 + ret = stat(command, &statBuf);
1.93 + if (ret < 0) {
1.94 + free(command);
1.95 + return PR_Open(shName, PR_RDONLY, 0);
1.96 + }
1.97 + /* file exits, make sure it's an executable */
1.98 + if (!S_ISREG(statBuf.st_mode) ||
1.99 + ((statBuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)) {
1.100 + free(command);
1.101 + return PR_Open(shName, PR_RDONLY, 0);
1.102 + }
1.103 +
1.104 + /* OK, the prelink command exists and looks correct, use it */
1.105 + /* build the arglist while we can still malloc */
1.106 + /* count the args if any */
1.107 + if (argString && *argString) {
1.108 + /* argString may have leading spaces, strip them off*/
1.109 + for (cp = argString; *cp && *cp == ' '; cp++);
1.110 + argString = cp;
1.111 + if (*cp) {
1.112 + /* there is at least one arg.. */
1.113 + argc = 1;
1.114 + }
1.115 +
1.116 + /* count the rest: Note there is no provision for escaped
1.117 + * spaces here */
1.118 + for (cp = argString; *cp ; cp++) {
1.119 + if (*cp == ' ') {
1.120 + while (*cp && *cp == ' ') cp++;
1.121 + if (*cp) argc++;
1.122 + }
1.123 + }
1.124 + }
1.125 +
1.126 + /* add the additional args: argv[0] (command), shName, NULL*/
1.127 + argc += 3;
1.128 + argv = PORT_NewArray(char *, argc);
1.129 + if (argv == NULL) {
1.130 + goto loser;
1.131 + }
1.132 +
1.133 + /* fill in the arglist */
1.134 + argv[argNext++] = command;
1.135 + if (argString && *argString) {
1.136 + argv[argNext++] = argString;
1.137 + for (cp = argString; *cp; cp++) {
1.138 + if (*cp == ' ') {
1.139 + *cp++ = 0;
1.140 + while (*cp && *cp == ' ') cp++;
1.141 + if (*cp) argv[argNext++] = cp;
1.142 + }
1.143 + }
1.144 + }
1.145 + /* exec doesn't advertise taking const char **argv, do the paranoid
1.146 + * copy */
1.147 + shNameArg = strdup(shName);
1.148 + if (shNameArg == NULL) {
1.149 + goto loser;
1.150 + }
1.151 + argv[argNext++] = shNameArg;
1.152 + argv[argNext++] = 0;
1.153 +
1.154 + ret = pipe(pipefd);
1.155 + if (ret < 0) {
1.156 + goto loser;
1.157 + }
1.158 +
1.159 + /* use vfork() so we don't trigger the pthread_at_fork() handlers */
1.160 + child = vfork();
1.161 + if (child < 0) goto loser;
1.162 + if (child == 0) {
1.163 + /* set up the file descriptors */
1.164 + /* if we need to support BSD, this will need to be an open of
1.165 + * /dev/null and dup2(nullFD, 0)*/
1.166 + close(0);
1.167 + /* associate pipefd[1] with stdout */
1.168 + if (pipefd[1] != 1) dup2(pipefd[1], 1);
1.169 + close(2);
1.170 + close(pipefd[0]);
1.171 + /* should probably close the other file descriptors? */
1.172 +
1.173 +
1.174 + execv(command, argv);
1.175 + /* avoid at_exit() handlers */
1.176 + _exit(1); /* shouldn't reach here except on an error */
1.177 + }
1.178 + close(pipefd[1]);
1.179 + pipefd[1] = -1;
1.180 +
1.181 + /* this is safe because either vfork() as full fork() semantics, and thus
1.182 + * already has it's own address space, or because vfork() has paused
1.183 + * the parent util the exec or exit */
1.184 + free(command);
1.185 + free(shNameArg);
1.186 + PORT_Free(argv);
1.187 +
1.188 + *pid = child;
1.189 +
1.190 + return PR_ImportPipe(pipefd[0]);
1.191 +
1.192 +loser:
1.193 + if (pipefd[0] != -1) {
1.194 + close(pipefd[0]);
1.195 + }
1.196 + if (pipefd[1] != -1) {
1.197 + close(pipefd[1]);
1.198 + }
1.199 + free(command);
1.200 + free(shNameArg);
1.201 + PORT_Free(argv);
1.202 +
1.203 + return NULL;
1.204 +}
1.205 +
1.206 +/*
1.207 + * bl_CloseUnPrelink -
1.208 + *
1.209 + * This closes the file descripter and reaps and children openned and crated by
1.210 + * b;_OpenUnprelink. It's primary difference between it and just close is
1.211 + * that it calls wait on the pid if one is supplied, preventing zombie children
1.212 + * from hanging around.
1.213 + */
1.214 +void
1.215 +bl_CloseUnPrelink( PRFileDesc *file, int pid)
1.216 +{
1.217 + /* close the file descriptor */
1.218 + PR_Close(file);
1.219 + /* reap the child */
1.220 + if (pid) {
1.221 + waitpid(pid, NULL, 0);
1.222 + }
1.223 +}
1.224 +#endif
1.225 +
1.226 +/* #define DEBUG_SHVERIFY 1 */
1.227 +
1.228 +static char *
1.229 +mkCheckFileName(const char *libName)
1.230 +{
1.231 + int ln_len = PORT_Strlen(libName);
1.232 + char *output = PORT_Alloc(ln_len+sizeof(SGN_SUFFIX));
1.233 + int index = ln_len + 1 - sizeof("."SHLIB_SUFFIX);
1.234 +
1.235 + if ((index > 0) &&
1.236 + (PORT_Strncmp(&libName[index],
1.237 + "."SHLIB_SUFFIX,sizeof("."SHLIB_SUFFIX)) == 0)) {
1.238 + ln_len = index;
1.239 + }
1.240 + PORT_Memcpy(output,libName,ln_len);
1.241 + PORT_Memcpy(&output[ln_len],SGN_SUFFIX,sizeof(SGN_SUFFIX));
1.242 + return output;
1.243 +}
1.244 +
1.245 +static int
1.246 +decodeInt(unsigned char *buf)
1.247 +{
1.248 + return (buf[3]) | (buf[2] << 8) | (buf[1] << 16) | (buf[0] << 24);
1.249 +}
1.250 +
1.251 +static SECStatus
1.252 +readItem(PRFileDesc *fd, SECItem *item)
1.253 +{
1.254 + unsigned char buf[4];
1.255 + int bytesRead;
1.256 +
1.257 +
1.258 + bytesRead = PR_Read(fd, buf, 4);
1.259 + if (bytesRead != 4) {
1.260 + return SECFailure;
1.261 + }
1.262 + item->len = decodeInt(buf);
1.263 +
1.264 + item->data = PORT_Alloc(item->len);
1.265 + if (item->data == NULL) {
1.266 + item->len = 0;
1.267 + return SECFailure;
1.268 + }
1.269 + bytesRead = PR_Read(fd, item->data, item->len);
1.270 + if (bytesRead != item->len) {
1.271 + PORT_Free(item->data);
1.272 + item->data = NULL;
1.273 + item->len = 0;
1.274 + return SECFailure;
1.275 + }
1.276 + return SECSuccess;
1.277 +}
1.278 +
1.279 +PRBool
1.280 +BLAPI_SHVerify(const char *name, PRFuncPtr addr)
1.281 +{
1.282 + PRBool result = PR_FALSE; /* if anything goes wrong,
1.283 + * the signature does not verify */
1.284 + /* find our shared library name */
1.285 + char *shName = PR_GetLibraryFilePathname(name, addr);
1.286 + if (!shName) {
1.287 + goto loser;
1.288 + }
1.289 + result = BLAPI_SHVerifyFile(shName);
1.290 +
1.291 +loser:
1.292 + if (shName != NULL) {
1.293 + PR_Free(shName);
1.294 + }
1.295 +
1.296 + return result;
1.297 +}
1.298 +
1.299 +PRBool
1.300 +BLAPI_SHVerifyFile(const char *shName)
1.301 +{
1.302 + char *checkName = NULL;
1.303 + PRFileDesc *checkFD = NULL;
1.304 + PRFileDesc *shFD = NULL;
1.305 + void *hashcx = NULL;
1.306 + const SECHashObject *hashObj = NULL;
1.307 + SECItem signature = { 0, NULL, 0 };
1.308 + SECItem hash;
1.309 + int bytesRead, offset;
1.310 + SECStatus rv;
1.311 + DSAPublicKey key;
1.312 + int count;
1.313 +#ifdef FREEBL_USE_PRELINK
1.314 + int pid = 0;
1.315 +#endif
1.316 +
1.317 + PRBool result = PR_FALSE; /* if anything goes wrong,
1.318 + * the signature does not verify */
1.319 + unsigned char buf[4096];
1.320 + unsigned char hashBuf[HASH_LENGTH_MAX];
1.321 +
1.322 + PORT_Memset(&key,0,sizeof(key));
1.323 + hash.data = hashBuf;
1.324 + hash.len = sizeof(hashBuf);
1.325 +
1.326 + if (!shName) {
1.327 + goto loser;
1.328 + }
1.329 +
1.330 + /* figure out the name of our check file */
1.331 + checkName = mkCheckFileName(shName);
1.332 + if (!checkName) {
1.333 + goto loser;
1.334 + }
1.335 +
1.336 + /* open the check File */
1.337 + checkFD = PR_Open(checkName, PR_RDONLY, 0);
1.338 + if (checkFD == NULL) {
1.339 +#ifdef DEBUG_SHVERIFY
1.340 + fprintf(stderr, "Failed to open the check file %s: (%d, %d)\n",
1.341 + checkName, (int)PR_GetError(), (int)PR_GetOSError());
1.342 +#endif /* DEBUG_SHVERIFY */
1.343 + goto loser;
1.344 + }
1.345 +
1.346 + /* read and Verify the headerthe header */
1.347 + bytesRead = PR_Read(checkFD, buf, 12);
1.348 + if (bytesRead != 12) {
1.349 + goto loser;
1.350 + }
1.351 + if ((buf[0] != NSS_SIGN_CHK_MAGIC1) || (buf[1] != NSS_SIGN_CHK_MAGIC2)) {
1.352 + goto loser;
1.353 + }
1.354 + if ((buf[2] != NSS_SIGN_CHK_MAJOR_VERSION) ||
1.355 + (buf[3] < NSS_SIGN_CHK_MINOR_VERSION)) {
1.356 + goto loser;
1.357 + }
1.358 +#ifdef notdef
1.359 + if (decodeInt(&buf[8]) != CKK_DSA) {
1.360 + goto loser;
1.361 + }
1.362 +#endif
1.363 +
1.364 + /* seek past any future header extensions */
1.365 + offset = decodeInt(&buf[4]);
1.366 + PR_Seek(checkFD, offset, PR_SEEK_SET);
1.367 +
1.368 + /* read the key */
1.369 + rv = readItem(checkFD,&key.params.prime);
1.370 + if (rv != SECSuccess) {
1.371 + goto loser;
1.372 + }
1.373 + rv = readItem(checkFD,&key.params.subPrime);
1.374 + if (rv != SECSuccess) {
1.375 + goto loser;
1.376 + }
1.377 + rv = readItem(checkFD,&key.params.base);
1.378 + if (rv != SECSuccess) {
1.379 + goto loser;
1.380 + }
1.381 + rv = readItem(checkFD,&key.publicValue);
1.382 + if (rv != SECSuccess) {
1.383 + goto loser;
1.384 + }
1.385 + /* read the siganture */
1.386 + rv = readItem(checkFD,&signature);
1.387 + if (rv != SECSuccess) {
1.388 + goto loser;
1.389 + }
1.390 +
1.391 + /* done with the check file */
1.392 + PR_Close(checkFD);
1.393 + checkFD = NULL;
1.394 +
1.395 + hashObj = HASH_GetRawHashObject(PQG_GetHashType(&key.params));
1.396 + if (hashObj == NULL) {
1.397 + goto loser;
1.398 + }
1.399 +
1.400 + /* open our library file */
1.401 +#ifdef FREEBL_USE_PRELINK
1.402 + shFD = bl_OpenUnPrelink(shName,&pid);
1.403 +#else
1.404 + shFD = PR_Open(shName, PR_RDONLY, 0);
1.405 +#endif
1.406 + if (shFD == NULL) {
1.407 +#ifdef DEBUG_SHVERIFY
1.408 + fprintf(stderr, "Failed to open the library file %s: (%d, %d)\n",
1.409 + shName, (int)PR_GetError(), (int)PR_GetOSError());
1.410 +#endif /* DEBUG_SHVERIFY */
1.411 + goto loser;
1.412 + }
1.413 +
1.414 + /* hash our library file with SHA1 */
1.415 + hashcx = hashObj->create();
1.416 + if (hashcx == NULL) {
1.417 + goto loser;
1.418 + }
1.419 + hashObj->begin(hashcx);
1.420 +
1.421 + count = 0;
1.422 + while ((bytesRead = PR_Read(shFD, buf, sizeof(buf))) > 0) {
1.423 + hashObj->update(hashcx, buf, bytesRead);
1.424 + count += bytesRead;
1.425 + }
1.426 +#ifdef FREEBL_USE_PRELINK
1.427 + bl_CloseUnPrelink(shFD, pid);
1.428 +#else
1.429 + PR_Close(shFD);
1.430 +#endif
1.431 + shFD = NULL;
1.432 +
1.433 + hashObj->end(hashcx, hash.data, &hash.len, hash.len);
1.434 +
1.435 +
1.436 + /* verify the hash against the check file */
1.437 + if (DSA_VerifyDigest(&key, &signature, &hash) == SECSuccess) {
1.438 + result = PR_TRUE;
1.439 + }
1.440 +#ifdef DEBUG_SHVERIFY
1.441 + {
1.442 + int i,j;
1.443 + fprintf(stderr,"File %s: %d bytes\n",shName, count);
1.444 + fprintf(stderr," hash: %d bytes\n", hash.len);
1.445 +#define STEP 10
1.446 + for (i=0; i < hash.len; i += STEP) {
1.447 + fprintf(stderr," ");
1.448 + for (j=0; j < STEP && (i+j) < hash.len; j++) {
1.449 + fprintf(stderr," %02x", hash.data[i+j]);
1.450 + }
1.451 + fprintf(stderr,"\n");
1.452 + }
1.453 + fprintf(stderr," signature: %d bytes\n", signature.len);
1.454 + for (i=0; i < signature.len; i += STEP) {
1.455 + fprintf(stderr," ");
1.456 + for (j=0; j < STEP && (i+j) < signature.len; j++) {
1.457 + fprintf(stderr," %02x", signature.data[i+j]);
1.458 + }
1.459 + fprintf(stderr,"\n");
1.460 + }
1.461 + fprintf(stderr,"Verified : %s\n",result?"TRUE": "FALSE");
1.462 + }
1.463 +#endif /* DEBUG_SHVERIFY */
1.464 +
1.465 +
1.466 +loser:
1.467 + if (checkName != NULL) {
1.468 + PORT_Free(checkName);
1.469 + }
1.470 + if (checkFD != NULL) {
1.471 + PR_Close(checkFD);
1.472 + }
1.473 + if (shFD != NULL) {
1.474 + PR_Close(shFD);
1.475 + }
1.476 + if (hashcx != NULL) {
1.477 + if (hashObj) {
1.478 + hashObj->destroy(hashcx,PR_TRUE);
1.479 + }
1.480 + }
1.481 + if (signature.data != NULL) {
1.482 + PORT_Free(signature.data);
1.483 + }
1.484 + if (key.params.prime.data != NULL) {
1.485 + PORT_Free(key.params.prime.data);
1.486 + }
1.487 + if (key.params.subPrime.data != NULL) {
1.488 + PORT_Free(key.params.subPrime.data);
1.489 + }
1.490 + if (key.params.base.data != NULL) {
1.491 + PORT_Free(key.params.base.data);
1.492 + }
1.493 + if (key.publicValue.data != NULL) {
1.494 + PORT_Free(key.publicValue.data);
1.495 + }
1.496 +
1.497 + return result;
1.498 +}
1.499 +
1.500 +PRBool
1.501 +BLAPI_VerifySelf(const char *name)
1.502 +{
1.503 + if (name == NULL) {
1.504 + /*
1.505 + * If name is NULL, freebl is statically linked into softoken.
1.506 + * softoken will call BLAPI_SHVerify next to verify itself.
1.507 + */
1.508 + return PR_TRUE;
1.509 + }
1.510 + return BLAPI_SHVerify(name, (PRFuncPtr) decodeInt);
1.511 +}
