Source code
Revision control
Copy as Markdown
Other Tools
/* 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
#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif
#include "shsign.h"
#include "prlink.h"
#include "prio.h"
#include "blapi.h"
#include "seccomon.h"
#include "secerr.h"
#include "stdio.h"
#include "prmem.h"
#include "hasht.h"
#include "pqg.h"
#include "blapii.h"
#include "secitem.h"
#include "pkcs11t.h"
#ifndef NSS_FIPS_DISABLED
/*
* 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;
/* 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
/* #define DEBUG_SHVERIFY 1 */
static char *
mkCheckFileName(const char *libName)
{
int ln_len = PORT_Strlen(libName);
int index = ln_len + 1 - sizeof("." SHLIB_SUFFIX);
char *output = PORT_Alloc(ln_len + sizeof(SGN_SUFFIX));
if (!output) {
PORT_SetError(SEC_ERROR_NO_MEMORY);
return NULL;
}
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;
}
static PRBool blapi_SHVerifyFile(const char *shName, PRBool self, PRBool rerun);
static PRBool
blapi_SHVerify(const char *name, PRFuncPtr addr, PRBool self, PRBool rerun)
{
PRBool result = PR_FALSE; /* if anything goes wrong,
* the signature does not verify */
/* find our shared library name */
char *shName = PR_GetLibraryFilePathname(name, addr);
if (!shName) {
goto loser;
}
result = blapi_SHVerifyFile(shName, self, rerun);
loser:
if (shName != NULL) {
PR_Free(shName);
}
return result;
}
PRBool
BLAPI_SHVerify(const char *name, PRFuncPtr addr)
{
PRBool rerun = PR_FALSE;
if (name && *name == BLAPI_FIPS_RERUN_FLAG) {
name++;
rerun = PR_TRUE;
}
return blapi_SHVerify(name, addr, PR_FALSE, rerun);
}
PRBool
BLAPI_SHVerifyFile(const char *shName)
{
PRBool rerun = PR_FALSE;
if (shName && *shName == BLAPI_FIPS_RERUN_FLAG) {
shName++;
rerun = PR_TRUE;
}
return blapi_SHVerifyFile(shName, PR_FALSE, rerun);
}
#ifndef NSS_STRICT_INTEGRITY
/* This allows checks with old shlibsign .chk files. If NSS_STRICT_INTEGRITY
* is set, we don't accept DSA */
static PRBool
blapi_SHVerifyDSACheck(PRFileDesc *shFD, const SECHashObject *hashObj,
DSAPublicKey *key, const SECItem *signature)
{
void *hashcx = NULL;
SECItem hash;
int bytesRead;
unsigned char hashBuf[HASH_LENGTH_MAX];
unsigned char buf[4096];
SECStatus rv;
hash.type = siBuffer;
hash.data = hashBuf;
hash.len = sizeof(hashBuf);
/* hash our library file */
hashcx = hashObj->create();
if (hashcx == NULL) {
return PR_FALSE;
}
hashObj->begin(hashcx);
while ((bytesRead = PR_Read(shFD, buf, sizeof(buf))) > 0) {
hashObj->update(hashcx, buf, bytesRead);
}
hashObj->end(hashcx, hash.data, &hash.len, hash.len);
hashObj->destroy(hashcx, PR_TRUE);
/* verify the hash against the check file */
rv = DSA_VerifyDigest(key, signature, &hash);
PORT_Memset(hashBuf, 0, sizeof hashBuf);
return (rv == SECSuccess) ? PR_TRUE : PR_FALSE;
}
#endif
#ifdef NSS_STRICT_INTEGRITY
/* don't allow MD2, MD5, SHA1 or SHA224 as your integrity hash */
static PRBool
blapi_HashAllowed(SECHashObject *hashObj)
{
switch (hashObj->type) {
case HASH_AlgSHA256:
case HASH_AlgSHA384:
case HASH_AlgSHA512:
return PR_TRUE;
default:
break;
}
return PR_FALSE;
}
#endif
static PRBool
blapi_SHVerifyHMACCheck(PRFileDesc *shFD, const SECHashObject *hashObj,
const SECItem *key, const SECItem *signature)
{
HMACContext *hmaccx = NULL;
SECItem hash;
int bytesRead;
unsigned char hashBuf[HASH_LENGTH_MAX];
unsigned char buf[4096];
SECStatus rv;
PRBool result = PR_FALSE;
#ifdef NSS_STRICT_INTEGRITY
if (!blapi_HashAllowed(hashObj)) {
return PR_FALSE;
}
#endif
hash.type = siBuffer;
hash.data = hashBuf;
hash.len = hashObj->length;
/* create an hmac for the library file */
hmaccx = HMAC_Create(hashObj, key->data, key->len, PR_TRUE);
if (hmaccx == NULL) {
return PR_FALSE;
}
HMAC_Begin(hmaccx);
while ((bytesRead = PR_Read(shFD, buf, sizeof(buf))) > 0) {
HMAC_Update(hmaccx, buf, bytesRead);
}
rv = HMAC_Finish(hmaccx, hash.data, &hash.len, hash.len);
HMAC_Destroy(hmaccx, PR_TRUE);
/* verify the hmac against the check file */
if (rv == SECSuccess) {
result = SECITEM_ItemsAreEqual(signature, &hash);
}
PORT_Memset(hashBuf, 0, sizeof hashBuf);
return result;
}
static PRBool
blapi_SHVerifyFile(const char *shName, PRBool self, PRBool rerun)
{
char *checkName = NULL;
PRFileDesc *checkFD = NULL;
PRFileDesc *shFD = NULL;
const SECHashObject *hashObj = NULL;
SECItem signature = { 0, NULL, 0 };
int bytesRead, offset, type;
SECStatus rv;
SECItem hmacKey = { 0, NULL, 0 };
#ifdef FREEBL_USE_PRELINK
int pid = 0;
#endif
PRBool result = PR_FALSE; /* if anything goes wrong,
* the signature does not verify */
NSSSignChkHeader header;
#ifndef NSS_STRICT_INTEGRITY
DSAPublicKey key;
PORT_Memset(&key, 0, sizeof(key));
#endif
/* If our integrity check was never ran or failed, fail any other
* integrity checks to prevent any token going into FIPS mode. */
if (!self && (BL_FIPSEntryOK(PR_FALSE, rerun) != SECSuccess)) {
return PR_FALSE;
}
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, &header, sizeof(header));
if (bytesRead != sizeof(header)) {
goto loser;
}
if ((header.magic1 != NSS_SIGN_CHK_MAGIC1) ||
(header.magic2 != NSS_SIGN_CHK_MAGIC2)) {
goto loser;
}
/* we've bumped the version number so that newly signed .check
* files will fail nicely on old version of nss */
if (header.majorVersion > NSS_SIGN_CHK_MAJOR_VERSION) {
goto loser;
}
if (header.minorVersion < NSS_SIGN_CHK_MINOR_VERSION) {
goto loser;
}
type = decodeInt(header.type);
/* seek past any future header extensions */
offset = decodeInt(header.offset);
if (PR_Seek(checkFD, offset, PR_SEEK_SET) < 0) {
goto loser;
}
switch (type) {
case CKK_DSA:
#ifdef NSS_STRICT_INTEGRITY
goto loser;
#else
/* accept old dsa check files if NSS_STRICT_INTEGRITY is not 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 signature */
rv = readItem(checkFD, &signature);
if (rv != SECSuccess) {
goto loser;
}
hashObj = HASH_GetRawHashObject(PQG_GetHashType(&key.params));
break;
#endif
default:
if ((type & NSS_SIGN_CHK_TYPE_FLAGS) != NSS_SIGN_CHK_FLAG_HMAC) {
goto loser;
}
/* read the HMAC Key */
rv = readItem(checkFD, &hmacKey);
if (rv != SECSuccess) {
goto loser;
}
/* read the siganture */
rv = readItem(checkFD, &signature);
if (rv != SECSuccess) {
goto loser;
}
hashObj = HASH_GetRawHashObject(type & ~NSS_SIGN_CHK_TYPE_FLAGS);
}
/* done with the check file */
PR_Close(checkFD);
checkFD = NULL;
if (hashObj == NULL) {
goto loser;
}
/* open our library file */
#ifdef FREEBL_USE_PRELINK
shFD = bl_OpenUnPrelink(shName, &pid);
#else
shFD = PR_Open(shName, PR_RDONLY, 0);
#endif
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;
}
switch (type) {
case CKK_DSA:
#ifndef NSS_STRICT_INTEGRITY
result = blapi_SHVerifyDSACheck(shFD, hashObj, &key, &signature);
#endif
break;
default:
if ((type & NSS_SIGN_CHK_TYPE_FLAGS) != NSS_SIGN_CHK_FLAG_HMAC) {
break;
}
result = blapi_SHVerifyHMACCheck(shFD, hashObj, &hmacKey, &signature);
break;
}
#ifdef FREEBL_USE_PRELINK
bl_CloseUnPrelink(shFD, pid);
#else
PR_Close(shFD);
#endif
shFD = NULL;
loser:
PORT_Memset(&header, 0, sizeof header);
if (checkName != NULL) {
PORT_Free(checkName);
}
if (checkFD != NULL) {
PR_Close(checkFD);
}
if (shFD != NULL) {
PR_Close(shFD);
}
if (hmacKey.data != NULL) {
SECITEM_ZfreeItem(&hmacKey, PR_FALSE);
}
if (signature.data != NULL) {
SECITEM_ZfreeItem(&signature, PR_FALSE);
}
#ifndef NSS_STRICT_INTEGRITY
if (key.params.prime.data != NULL) {
SECITEM_ZfreeItem(&key.params.prime, PR_FALSE);
}
if (key.params.subPrime.data != NULL) {
SECITEM_ZfreeItem(&key.params.subPrime, PR_FALSE);
}
if (key.params.base.data != NULL) {
SECITEM_ZfreeItem(&key.params.base, PR_FALSE);
}
if (key.publicValue.data != NULL) {
SECITEM_ZfreeItem(&key.publicValue, PR_FALSE);
}
#endif
return result;
}
PRBool
BLAPI_VerifySelf(const char *name)
{
if (name == NULL) {
/*
* If name is NULL, freebl is statically linked into softoken.
* softoken will call BLAPI_SHVerify next to verify itself.
*/
return PR_TRUE;
}
return blapi_SHVerify(name, (PRFuncPtr)decodeInt, PR_TRUE, PR_FALSE);
}
#else /* NSS_FIPS_DISABLED */
PRBool
BLAPI_SHVerifyFile(const char *shName)
{
return PR_FALSE;
}
PRBool
BLAPI_SHVerify(const char *name, PRFuncPtr addr)
{
return PR_FALSE;
}
PRBool
BLAPI_VerifySelf(const char *name)
{
return PR_FALSE;
}
#endif /* NSS_FIPS_DISABLED */