RetroZilla/security/nss/lib/freebl/shvfy.c

509 lines
12 KiB
C
Raw Normal View History

2015-10-21 05:03:22 +02:00
2018-05-04 16:08:28 +02:00
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
2015-10-21 05:03:22 +02:00
#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif
#include "shsign.h"
#include "prlink.h"
#include "prio.h"
#include "blapi.h"
#include "seccomon.h"
#include "stdio.h"
#include "prmem.h"
2018-05-04 16:08:28 +02:00
#include "hasht.h"
#include "pqg.h"
/*
* Most modern version of Linux support a speed optimization scheme where an
* application called prelink modifies programs and shared libraries to quickly
* load if they fit into an already designed address space. In short, prelink
* scans the list of programs and libraries on your system, assigns them a
* predefined space in the the address space, then provides the fixups to the
* library.
* The modification of the shared library is correctly detected by the freebl
* FIPS checksum scheme where we check a signed hash of the library against the
* library itself.
*
* The prelink command itself can reverse the process of modification and
* output the prestine shared library as it was before prelink made it's
* changes. If FREEBL_USE_PRELINK is set Freebl uses prelink to output the
* original copy of the shared library before prelink modified it.
*/
#ifdef FREEBL_USE_PRELINK
#ifndef FREELB_PRELINK_COMMAND
#define FREEBL_PRELINK_COMMAND "/usr/sbin/prelink -u -o -"
#endif
#include "private/pprio.h"
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <sys/stat.h>
/*
* This function returns an NSPR PRFileDesc * which the caller can read to
* obtain the prestine value of the shared library, before any OS related
* changes to it (usually address fixups).
*
* If prelink is installed, this
* file descriptor is a pipe connecting the output of
* /usr/sbin/prelink -u -o - {Library}
* and *pid returns the process id of the prelink child.
*
* If prelink is not installed, it returns a normal readonly handle to the
* library itself and *pid is set to '0'.
*/
PRFileDesc *
bl_OpenUnPrelink(const char *shName, int *pid)
{
char *command= strdup(FREEBL_PRELINK_COMMAND);
char *argString = NULL;
char **argv = NULL;
char *shNameArg = NULL;
char *cp;
pid_t child;
int argc = 0, argNext = 0;
struct stat statBuf;
int pipefd[2] = {-1,-1};
int ret;
*pid = 0;
/* make sure the prelink command exists first. If not, fall back to
* just reading the file */
for (cp = command; *cp ; cp++) {
if (*cp == ' ') {
*cp++ = 0;
argString = cp;
break;
}
}
memset (&statBuf, 0, sizeof(statBuf));
/* stat the file, follow the link */
ret = stat(command, &statBuf);
if (ret < 0) {
free(command);
return PR_Open(shName, PR_RDONLY, 0);
}
/* file exits, make sure it's an executable */
if (!S_ISREG(statBuf.st_mode) ||
((statBuf.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)) {
free(command);
return PR_Open(shName, PR_RDONLY, 0);
}
/* OK, the prelink command exists and looks correct, use it */
/* build the arglist while we can still malloc */
/* count the args if any */
if (argString && *argString) {
/* argString may have leading spaces, strip them off*/
for (cp = argString; *cp && *cp == ' '; cp++);
argString = cp;
if (*cp) {
/* there is at least one arg.. */
argc = 1;
}
/* count the rest: Note there is no provision for escaped
* spaces here */
for (cp = argString; *cp ; cp++) {
if (*cp == ' ') {
while (*cp && *cp == ' ') cp++;
if (*cp) argc++;
}
}
}
/* add the additional args: argv[0] (command), shName, NULL*/
argc += 3;
argv = PORT_NewArray(char *, argc);
if (argv == NULL) {
goto loser;
}
/* fill in the arglist */
argv[argNext++] = command;
if (argString && *argString) {
argv[argNext++] = argString;
for (cp = argString; *cp; cp++) {
if (*cp == ' ') {
*cp++ = 0;
while (*cp && *cp == ' ') cp++;
if (*cp) argv[argNext++] = cp;
}
}
}
/* exec doesn't advertise taking const char **argv, do the paranoid
* copy */
shNameArg = strdup(shName);
if (shNameArg == NULL) {
goto loser;
}
argv[argNext++] = shNameArg;
argv[argNext++] = 0;
ret = pipe(pipefd);
if (ret < 0) {
goto loser;
}
/* use vfork() so we don't trigger the pthread_at_fork() handlers */
child = vfork();
if (child < 0) goto loser;
if (child == 0) {
/* set up the file descriptors */
/* if we need to support BSD, this will need to be an open of
* /dev/null and dup2(nullFD, 0)*/
close(0);
/* associate pipefd[1] with stdout */
if (pipefd[1] != 1) dup2(pipefd[1], 1);
close(2);
close(pipefd[0]);
/* should probably close the other file descriptors? */
execv(command, argv);
/* avoid at_exit() handlers */
_exit(1); /* shouldn't reach here except on an error */
}
close(pipefd[1]);
pipefd[1] = -1;
2015-10-21 05:03:22 +02:00
2018-05-04 16:08:28 +02:00
/* this is safe because either vfork() as full fork() semantics, and thus
* already has it's own address space, or because vfork() has paused
* the parent util the exec or exit */
free(command);
free(shNameArg);
PORT_Free(argv);
*pid = child;
return PR_ImportPipe(pipefd[0]);
loser:
if (pipefd[0] != -1) {
close(pipefd[0]);
}
if (pipefd[1] != -1) {
close(pipefd[1]);
}
free(command);
free(shNameArg);
PORT_Free(argv);
return NULL;
}
/*
* bl_CloseUnPrelink -
*
* This closes the file descripter and reaps and children openned and crated by
* b;_OpenUnprelink. It's primary difference between it and just close is
* that it calls wait on the pid if one is supplied, preventing zombie children
* from hanging around.
*/
void
bl_CloseUnPrelink( PRFileDesc *file, int pid)
{
/* close the file descriptor */
PR_Close(file);
/* reap the child */
if (pid) {
waitpid(pid, NULL, 0);
}
}
#endif
2015-10-21 05:03:22 +02:00
/* #define DEBUG_SHVERIFY 1 */
static char *
mkCheckFileName(const char *libName)
{
int ln_len = PORT_Strlen(libName);
char *output = PORT_Alloc(ln_len+sizeof(SGN_SUFFIX));
int index = ln_len + 1 - sizeof("."SHLIB_SUFFIX);
if ((index > 0) &&
(PORT_Strncmp(&libName[index],
"."SHLIB_SUFFIX,sizeof("."SHLIB_SUFFIX)) == 0)) {
ln_len = index;
}
PORT_Memcpy(output,libName,ln_len);
PORT_Memcpy(&output[ln_len],SGN_SUFFIX,sizeof(SGN_SUFFIX));
return output;
}
static int
decodeInt(unsigned char *buf)
{
return (buf[3]) | (buf[2] << 8) | (buf[1] << 16) | (buf[0] << 24);
}
static SECStatus
readItem(PRFileDesc *fd, SECItem *item)
{
unsigned char buf[4];
int bytesRead;
bytesRead = PR_Read(fd, buf, 4);
if (bytesRead != 4) {
return SECFailure;
}
item->len = decodeInt(buf);
item->data = PORT_Alloc(item->len);
if (item->data == NULL) {
item->len = 0;
return SECFailure;
}
bytesRead = PR_Read(fd, item->data, item->len);
if (bytesRead != item->len) {
PORT_Free(item->data);
item->data = NULL;
item->len = 0;
return SECFailure;
}
return SECSuccess;
}
PRBool
BLAPI_SHVerify(const char *name, PRFuncPtr addr)
{
2018-05-04 16:08:28 +02:00
PRBool result = PR_FALSE; /* if anything goes wrong,
* the signature does not verify */
2015-10-21 05:03:22 +02:00
/* find our shared library name */
char *shName = PR_GetLibraryFilePathname(name, addr);
2018-05-04 16:08:28 +02:00
if (!shName) {
goto loser;
}
result = BLAPI_SHVerifyFile(shName);
loser:
if (shName != NULL) {
PR_Free(shName);
}
return result;
}
PRBool
BLAPI_SHVerifyFile(const char *shName)
{
2015-10-21 05:03:22 +02:00
char *checkName = NULL;
PRFileDesc *checkFD = NULL;
PRFileDesc *shFD = NULL;
2018-05-04 16:08:28 +02:00
void *hashcx = NULL;
const SECHashObject *hashObj = NULL;
2015-10-21 05:03:22 +02:00
SECItem signature = { 0, NULL, 0 };
SECItem hash;
int bytesRead, offset;
SECStatus rv;
DSAPublicKey key;
int count;
2018-05-04 16:08:28 +02:00
#ifdef FREEBL_USE_PRELINK
int pid = 0;
#endif
2015-10-21 05:03:22 +02:00
PRBool result = PR_FALSE; /* if anything goes wrong,
* the signature does not verify */
2018-05-04 16:08:28 +02:00
unsigned char buf[4096];
unsigned char hashBuf[HASH_LENGTH_MAX];
2015-10-21 05:03:22 +02:00
PORT_Memset(&key,0,sizeof(key));
hash.data = hashBuf;
hash.len = sizeof(hashBuf);
if (!shName) {
goto loser;
}
/* figure out the name of our check file */
checkName = mkCheckFileName(shName);
if (!checkName) {
goto loser;
}
/* open the check File */
checkFD = PR_Open(checkName, PR_RDONLY, 0);
if (checkFD == NULL) {
#ifdef DEBUG_SHVERIFY
fprintf(stderr, "Failed to open the check file %s: (%d, %d)\n",
checkName, (int)PR_GetError(), (int)PR_GetOSError());
#endif /* DEBUG_SHVERIFY */
goto loser;
}
/* read and Verify the headerthe header */
bytesRead = PR_Read(checkFD, buf, 12);
if (bytesRead != 12) {
goto loser;
}
if ((buf[0] != NSS_SIGN_CHK_MAGIC1) || (buf[1] != NSS_SIGN_CHK_MAGIC2)) {
goto loser;
}
if ((buf[2] != NSS_SIGN_CHK_MAJOR_VERSION) ||
(buf[3] < NSS_SIGN_CHK_MINOR_VERSION)) {
goto loser;
}
#ifdef notdef
if (decodeInt(&buf[8]) != CKK_DSA) {
goto loser;
}
#endif
/* seek past any future header extensions */
offset = decodeInt(&buf[4]);
PR_Seek(checkFD, offset, PR_SEEK_SET);
/* read the key */
rv = readItem(checkFD,&key.params.prime);
if (rv != SECSuccess) {
goto loser;
}
rv = readItem(checkFD,&key.params.subPrime);
if (rv != SECSuccess) {
goto loser;
}
rv = readItem(checkFD,&key.params.base);
if (rv != SECSuccess) {
goto loser;
}
rv = readItem(checkFD,&key.publicValue);
if (rv != SECSuccess) {
goto loser;
}
/* read the siganture */
rv = readItem(checkFD,&signature);
if (rv != SECSuccess) {
goto loser;
}
/* done with the check file */
PR_Close(checkFD);
checkFD = NULL;
2018-05-04 16:08:28 +02:00
hashObj = HASH_GetRawHashObject(PQG_GetHashType(&key.params));
if (hashObj == NULL) {
goto loser;
}
2015-10-21 05:03:22 +02:00
/* open our library file */
2018-05-04 16:08:28 +02:00
#ifdef FREEBL_USE_PRELINK
shFD = bl_OpenUnPrelink(shName,&pid);
#else
2015-10-21 05:03:22 +02:00
shFD = PR_Open(shName, PR_RDONLY, 0);
2018-05-04 16:08:28 +02:00
#endif
2015-10-21 05:03:22 +02:00
if (shFD == NULL) {
#ifdef DEBUG_SHVERIFY
fprintf(stderr, "Failed to open the library file %s: (%d, %d)\n",
shName, (int)PR_GetError(), (int)PR_GetOSError());
#endif /* DEBUG_SHVERIFY */
goto loser;
}
/* hash our library file with SHA1 */
2018-05-04 16:08:28 +02:00
hashcx = hashObj->create();
2015-10-21 05:03:22 +02:00
if (hashcx == NULL) {
goto loser;
}
2018-05-04 16:08:28 +02:00
hashObj->begin(hashcx);
2015-10-21 05:03:22 +02:00
count = 0;
while ((bytesRead = PR_Read(shFD, buf, sizeof(buf))) > 0) {
2018-05-04 16:08:28 +02:00
hashObj->update(hashcx, buf, bytesRead);
2015-10-21 05:03:22 +02:00
count += bytesRead;
}
2018-05-04 16:08:28 +02:00
#ifdef FREEBL_USE_PRELINK
bl_CloseUnPrelink(shFD, pid);
#else
2015-10-21 05:03:22 +02:00
PR_Close(shFD);
2018-05-04 16:08:28 +02:00
#endif
2015-10-21 05:03:22 +02:00
shFD = NULL;
2018-05-04 16:08:28 +02:00
hashObj->end(hashcx, hash.data, &hash.len, hash.len);
2015-10-21 05:03:22 +02:00
/* verify the hash against the check file */
if (DSA_VerifyDigest(&key, &signature, &hash) == SECSuccess) {
result = PR_TRUE;
}
#ifdef DEBUG_SHVERIFY
{
int i,j;
fprintf(stderr,"File %s: %d bytes\n",shName, count);
fprintf(stderr," hash: %d bytes\n", hash.len);
#define STEP 10
for (i=0; i < hash.len; i += STEP) {
fprintf(stderr," ");
for (j=0; j < STEP && (i+j) < hash.len; j++) {
fprintf(stderr," %02x", hash.data[i+j]);
}
fprintf(stderr,"\n");
}
fprintf(stderr," signature: %d bytes\n", signature.len);
for (i=0; i < signature.len; i += STEP) {
fprintf(stderr," ");
for (j=0; j < STEP && (i+j) < signature.len; j++) {
fprintf(stderr," %02x", signature.data[i+j]);
}
fprintf(stderr,"\n");
}
fprintf(stderr,"Verified : %s\n",result?"TRUE": "FALSE");
}
#endif /* DEBUG_SHVERIFY */
loser:
if (checkName != NULL) {
PORT_Free(checkName);
}
if (checkFD != NULL) {
PR_Close(checkFD);
}
if (shFD != NULL) {
PR_Close(shFD);
}
if (hashcx != NULL) {
2018-05-04 16:08:28 +02:00
if (hashObj) {
hashObj->destroy(hashcx,PR_TRUE);
}
2015-10-21 05:03:22 +02:00
}
if (signature.data != NULL) {
PORT_Free(signature.data);
}
if (key.params.prime.data != NULL) {
PORT_Free(key.params.prime.data);
}
if (key.params.subPrime.data != NULL) {
PORT_Free(key.params.subPrime.data);
}
if (key.params.base.data != NULL) {
PORT_Free(key.params.base.data);
}
if (key.publicValue.data != NULL) {
PORT_Free(key.publicValue.data);
}
return result;
}
PRBool
BLAPI_VerifySelf(const char *name)
{
if (name == NULL) {
2018-05-04 16:08:28 +02:00
/*
* If name is NULL, freebl is statically linked into softoken.
* softoken will call BLAPI_SHVerify next to verify itself.
*/
2015-10-21 05:03:22 +02:00
return PR_TRUE;
}
return BLAPI_SHVerify(name, (PRFuncPtr) decodeInt);
}