+++ /dev/null
-/*
- rsa.c -- RSA key handling
- Copyright (C) 2007-2012 Guus Sliepen <guus@tinc-vpn.org>
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
- This program is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
-*/
-
-#include "system.h"
-
-#include <gcrypt.h>
-
-#include "logger.h"
-#include "rsa.h"
-
-// Base64 decoding table
-
-static const uint8_t b64d[128] = {
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
- 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
- 0x3a, 0x3b, 0x3c, 0x3d, 0xff, 0xff,
- 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
- 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
- 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c,
- 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12,
- 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
- 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
- 0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e,
- 0x1f, 0x20, 0x21, 0x22, 0x23, 0x24,
- 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a,
- 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
- 0x31, 0x32, 0x33, 0xff, 0xff, 0xff,
- 0xff, 0xff
-};
-
-// PEM encoding/decoding functions
-
-static bool pem_decode(FILE *fp, const char *header, uint8_t *buf, size_t size, size_t *outsize) {
- bool decode = false;
- char line[1024];
- uint16_t word = 0;
- int shift = 10;
- size_t i, j = 0;
-
- while(!feof(fp)) {
- if(!fgets(line, sizeof line, fp))
- return false;
-
- if(!decode && !strncmp(line, "-----BEGIN ", 11)) {
- if(!strncmp(line + 11, header, strlen(header)))
- decode = true;
- continue;
- }
-
- if(decode && !strncmp(line, "-----END", 8)) {
- break;
- }
-
- if(!decode)
- continue;
-
- for(i = 0; line[i] >= ' '; i++) {
- if((signed char)line[i] < 0 || b64d[(int)line[i]] == 0xff)
- break;
- word |= b64d[(int)line[i]] << shift;
- shift -= 6;
- if(shift <= 2) {
- if(j > size) {
- errno = ENOMEM;
- return false;
- }
-
- buf[j++] = word >> 8;
- word <<= 8;
- shift += 8;
- }
- }
- }
-
- if(outsize)
- *outsize = j;
- return true;
-}
-
-
-// BER decoding functions
-
-static int ber_read_id(unsigned char **p, size_t *buflen) {
- if(*buflen <= 0)
- return -1;
-
- if((**p & 0x1f) == 0x1f) {
- int id = 0;
- bool more;
- while(*buflen > 0) {
- id <<= 7;
- id |= **p & 0x7f;
- more = *(*p)++ & 0x80;
- (*buflen)--;
- if(!more)
- break;
- }
- return id;
- } else {
- (*buflen)--;
- return *(*p)++ & 0x1f;
- }
-}
-
-static size_t ber_read_len(unsigned char **p, size_t *buflen) {
- if(*buflen <= 0)
- return -1;
-
- if(**p & 0x80) {
- size_t result = 0;
- int len = *(*p)++ & 0x7f;
- (*buflen)--;
- if(len > *buflen)
- return 0;
-
- while(len--) {
- result <<= 8;
- result |= *(*p)++;
- (*buflen)--;
- }
-
- return result;
- } else {
- (*buflen)--;
- return *(*p)++;
- }
-}
-
-
-static bool ber_read_sequence(unsigned char **p, size_t *buflen, size_t *result) {
- int tag = ber_read_id(p, buflen);
- size_t len = ber_read_len(p, buflen);
-
- if(tag == 0x10) {
- if(result)
- *result = len;
- return true;
- } else {
- return false;
- }
-}
-
-static bool ber_read_mpi(unsigned char **p, size_t *buflen, gcry_mpi_t *mpi) {
- int tag = ber_read_id(p, buflen);
- size_t len = ber_read_len(p, buflen);
- gcry_error_t err = 0;
-
- if(tag != 0x02 || len > *buflen)
- return false;
-
- if(mpi)
- err = gcry_mpi_scan(mpi, GCRYMPI_FMT_USG, *p, len, NULL);
-
- *p += len;
- *buflen -= len;
-
- return mpi ? !err : true;
-}
-
-bool rsa_set_hex_public_key(rsa_t *rsa, char *n, char *e) {
- gcry_error_t err = 0;
-
- err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL)
- ?: gcry_mpi_scan(&rsa->e, GCRYMPI_FMT_HEX, e, 0, NULL);
-
- if(err) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno));
- return false;
- }
-
- return true;
-}
-
-bool rsa_set_hex_private_key(rsa_t *rsa, char *n, char *e, char *d) {
- gcry_error_t err = 0;
-
- err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL)
- ?: gcry_mpi_scan(&rsa->e, GCRYMPI_FMT_HEX, e, 0, NULL)
- ?: gcry_mpi_scan(&rsa->d, GCRYMPI_FMT_HEX, d, 0, NULL);
-
- if(err) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno));
- return false;
- }
-
- return true;
-}
-
-// Read PEM RSA keys
-
-bool rsa_read_pem_public_key(rsa_t *rsa, FILE *fp) {
- uint8_t derbuf[8096], *derp = derbuf;
- size_t derlen;
-
- if(!pem_decode(fp, "RSA PUBLIC KEY", derbuf, sizeof derbuf, &derlen)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Unable to read RSA public key: %s", strerror(errno));
- return NULL;
- }
-
- if(!ber_read_sequence(&derp, &derlen, NULL)
- || !ber_read_mpi(&derp, &derlen, &rsa->n)
- || !ber_read_mpi(&derp, &derlen, &rsa->e)
- || derlen) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decoding RSA public key");
- return NULL;
- }
-
- return true;
-}
-
-bool rsa_read_pem_private_key(rsa_t *rsa, FILE *fp) {
- uint8_t derbuf[8096], *derp = derbuf;
- size_t derlen;
-
- if(!pem_decode(fp, "RSA PRIVATE KEY", derbuf, sizeof derbuf, &derlen)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Unable to read RSA private key: %s", strerror(errno));
- return NULL;
- }
-
- if(!ber_read_sequence(&derp, &derlen, NULL)
- || !ber_read_mpi(&derp, &derlen, NULL)
- || !ber_read_mpi(&derp, &derlen, &rsa->n)
- || !ber_read_mpi(&derp, &derlen, &rsa->e)
- || !ber_read_mpi(&derp, &derlen, &rsa->d)
- || !ber_read_mpi(&derp, &derlen, NULL) // p
- || !ber_read_mpi(&derp, &derlen, NULL) // q
- || !ber_read_mpi(&derp, &derlen, NULL)
- || !ber_read_mpi(&derp, &derlen, NULL)
- || !ber_read_mpi(&derp, &derlen, NULL) // u
- || derlen) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decoding RSA private key");
- return NULL;
- }
-
- return true;
-}
-
-size_t rsa_size(rsa_t *rsa) {
- return (gcry_mpi_get_nbits(rsa->n) + 7) / 8;
-}
-
-/* Well, libgcrypt has functions to handle RSA keys, but they suck.
- * So we just use libgcrypt's mpi functions, and do the math ourselves.
- */
-
-// TODO: get rid of this macro, properly clean up gcry_ structures after use
-#define check(foo) { gcry_error_t err = (foo); if(err) {logger(DEBUG_ALWAYS, LOG_ERR, "gcrypt error %s/%s at %s:%d", gcry_strsource(err), gcry_strerror(err), __FILE__, __LINE__); return false; }}
-
-bool rsa_public_encrypt(rsa_t *rsa, void *in, size_t len, void *out) {
- gcry_mpi_t inmpi;
- check(gcry_mpi_scan(&inmpi, GCRYMPI_FMT_USG, in, len, NULL));
-
- gcry_mpi_t outmpi = gcry_mpi_new(len * 8);
- gcry_mpi_powm(outmpi, inmpi, rsa->e, rsa->n);
-
- int pad = len - (gcry_mpi_get_nbits(outmpi) + 7) / 8;
- while(pad--)
- *(char *)out++ = 0;
-
- check(gcry_mpi_print(GCRYMPI_FMT_USG, out,len, NULL, outmpi));
-
- return true;
-}
-
-bool rsa_private_decrypt(rsa_t *rsa, void *in, size_t len, void *out) {
- gcry_mpi_t inmpi;
- check(gcry_mpi_scan(&inmpi, GCRYMPI_FMT_USG, in, len, NULL));
-
- gcry_mpi_t outmpi = gcry_mpi_new(len * 8);
- gcry_mpi_powm(outmpi, inmpi, rsa->d, rsa->n);
-
- int pad = len - (gcry_mpi_get_nbits(outmpi) + 7) / 8;
- while(pad--)
- *(char *)out++ = 0;
-
- check(gcry_mpi_print(GCRYMPI_FMT_USG, out,len, NULL, outmpi));
-
- return true;
-}
projects / meshlink / blobdiff