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 /* 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/. */

 #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"

 #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;

     /* 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);

     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)

 {

     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);

 loser:

     if (shName != NULL) {

 	PR_Free(shName);

     }

     return result;

 }

 PRBool

 BLAPI_SHVerifyFile(const char *shName)

 {

     char *checkName = NULL;

     PRFileDesc *checkFD = NULL;

     PRFileDesc *shFD = NULL;

     void  *hashcx = NULL;

     const SECHashObject *hashObj = NULL;

     SECItem signature = { 0, NULL, 0 };

     SECItem hash;

     int bytesRead, offset;

     SECStatus rv;

     DSAPublicKey key;

     int count;

 #ifdef FREEBL_USE_PRELINK

     int pid = 0;

 #endif

     PRBool result = PR_FALSE; /* if anything goes wrong,

 			       * the signature does not verify */

     unsigned char buf[4096];

     unsigned char hashBuf[HASH_LENGTH_MAX];

     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;

     hashObj = HASH_GetRawHashObject(PQG_GetHashType(&key.params));

     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;

     }

     /* hash our library file with SHA1 */

     hashcx = hashObj->create();

     if (hashcx == NULL) {

 	goto loser;

     }

     hashObj->begin(hashcx);

     count = 0;

     while ((bytesRead = PR_Read(shFD, buf, sizeof(buf))) > 0) {

 	hashObj->update(hashcx, buf, bytesRead);

 	count += bytesRead;

     }

 #ifdef FREEBL_USE_PRELINK

     bl_CloseUnPrelink(shFD, pid);

 #else

     PR_Close(shFD);

 #endif

     shFD = NULL;

     hashObj->end(hashcx, hash.data, &hash.len, hash.len);

     /* 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) {

 	if (hashObj) {

 	    hashObj->destroy(hashcx,PR_TRUE);

 	}

     }

     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) {

 	/*

 	 * 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);

 }