X-Git-Url: https://www.tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fgcrypt%2Frsa.c;h=83f177b8084e31c0c181bcfb9c5415a917b91c62;hb=c44b08613508c993e7fd9f625e0b1b4775efffed;hp=62a21290f28b6c302b8cd949f81e0e79b5d2c09b;hpb=761517c21c37a808a19b487aa116c3c19439feca;p=tinc diff --git a/src/gcrypt/rsa.c b/src/gcrypt/rsa.c index 62a21290..83f177b8 100644 --- a/src/gcrypt/rsa.c +++ b/src/gcrypt/rsa.c @@ -1,6 +1,6 @@ /* rsa.c -- RSA key handling - Copyright (C) 2007 Guus Sliepen + Copyright (C) 2007-2022 Guus Sliepen 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 @@ -17,107 +17,39 @@ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ -#include "system.h" +#include "../system.h" #include -#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; -} +#include "pem.h" +#include "rsa.h" +#include "../logger.h" +#include "../rsa.h" +#include "../xalloc.h" // BER decoding functions static int ber_read_id(unsigned char **p, size_t *buflen) { - if(*buflen <= 0) + 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) + + if(!more) { break; + } } + return id; } else { (*buflen)--; @@ -126,18 +58,21 @@ static int ber_read_id(unsigned char **p, size_t *buflen) { } static size_t ber_read_len(unsigned char **p, size_t *buflen) { - if(*buflen <= 0) + if(*buflen <= 0) { return -1; + } if(**p & 0x80) { size_t result = 0; - int len = *(*p)++ & 0x7f; + size_t len = *(*p)++ & 0x7f; (*buflen)--; - if(len > *buflen) + + if(len > *buflen) { return 0; + } - while(len--) { - result <<= 8; + for(; len; --len) { + result = (size_t)(result << 8); result |= *(*p)++; (*buflen)--; } @@ -148,15 +83,17 @@ static size_t ber_read_len(unsigned char **p, size_t *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) + if(result) { *result = len; + } + return true; } else { return false; @@ -168,127 +105,180 @@ static bool ber_read_mpi(unsigned char **p, size_t *buflen, gcry_mpi_t *mpi) { size_t len = ber_read_len(p, buflen); gcry_error_t err = 0; - if(tag != 0x02 || len > *buflen) + if(tag != 0x02 || len > *buflen) { return false; + } - if(mpi) + 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; +rsa_t *rsa_set_hex_public_key(const char *n, const char *e) { + rsa_t *rsa = xzalloc(sizeof(rsa_t)); + + gcry_error_t err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL); - err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL) - ?: gcry_mpi_scan(&rsa->e, GCRYMPI_FMT_HEX, n, 0, NULL); + if(!err) { + err = gcry_mpi_scan(&rsa->e, GCRYMPI_FMT_HEX, e, 0, NULL); + } if(err) { - logger(LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno)); + logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno)); + rsa_free(rsa); return false; } - return true; + return rsa; } -bool rsa_set_hex_private_key(rsa_t *rsa, char *n, char *e, char *d) { - gcry_error_t err = 0; +rsa_t *rsa_set_hex_private_key(const char *n, const char *e, const char *d) { + rsa_t *rsa = xzalloc(sizeof(rsa_t)); + + gcry_error_t err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL); + + if(!err) { + err = gcry_mpi_scan(&rsa->e, GCRYMPI_FMT_HEX, e, 0, NULL); + } - err = gcry_mpi_scan(&rsa->n, GCRYMPI_FMT_HEX, n, 0, NULL) - ?: gcry_mpi_scan(&rsa->e, GCRYMPI_FMT_HEX, n, 0, NULL) - ?: gcry_mpi_scan(&rsa->d, GCRYMPI_FMT_HEX, n, 0, NULL); + if(!err) { + err = gcry_mpi_scan(&rsa->d, GCRYMPI_FMT_HEX, d, 0, NULL); + } if(err) { - logger(LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno)); - return false; + logger(DEBUG_ALWAYS, LOG_ERR, "Error while reading RSA public key: %s", gcry_strerror(errno)); + rsa_free(rsa); + return NULL; } - return true; + return rsa; } // Read PEM RSA keys -bool rsa_read_pem_public_key(rsa_t *rsa, FILE *fp) { +rsa_t *rsa_read_pem_public_key(FILE *fp) { uint8_t derbuf[8096], *derp = derbuf; size_t derlen; - if(!pem_decode(fp, "RSA PUBLIC KEY", derbuf, sizeof derbuf, &derlen)) { - logger(LOG_ERR, "Unable to read RSA public key: %s", strerror(errno)); + 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; } + rsa_t *rsa = xzalloc(sizeof(rsa_t)); + if(!ber_read_sequence(&derp, &derlen, NULL) - || !ber_read_mpi(&derp, &derlen, &rsa->n) - || !ber_read_mpi(&derp, &derlen, &rsa->e) - || derlen) { - logger(LOG_ERR, "Error while decoding RSA public key"); + || !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"); + rsa_free(rsa); return NULL; } - return true; + return rsa; } -bool rsa_read_pem_private_key(rsa_t *rsa, FILE *fp) { +rsa_t *rsa_read_pem_private_key(FILE *fp) { uint8_t derbuf[8096], *derp = derbuf; size_t derlen; - if(!pem_decode(fp, "RSA PRIVATE KEY", derbuf, sizeof derbuf, &derlen)) { - logger(LOG_ERR, "Unable to read RSA private key: %s", strerror(errno)); + 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; } + rsa_t *rsa = xzalloc(sizeof(rsa_t)); + 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(LOG_ERR, "Error while decoding RSA private key"); - return 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"); + rsa_free(rsa); + rsa = NULL; } - return true; + memzero(derbuf, sizeof(derbuf)); + return rsa; } -size_t rsa_size(rsa_t *rsa) { +size_t rsa_size(const rsa_t *rsa) { return (gcry_mpi_get_nbits(rsa->n) + 7) / 8; } +static bool check(gcry_error_t err) { + if(err) { + logger(DEBUG_ALWAYS, LOG_ERR, "gcrypt error %s/%s", gcry_strsource(err), gcry_strerror(err)); + } + + return !err; +} + /* 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(LOG_ERR, "gcrypt error %s/%s at %s:%d\n", gcry_strsource(err), gcry_strerror(err), __FILE__, __LINE__); return false; }} +static bool rsa_powm(const gcry_mpi_t ed, const gcry_mpi_t n, const void *in, size_t len, void *out) { + gcry_mpi_t inmpi = NULL; + + if(!check(gcry_mpi_scan(&inmpi, GCRYMPI_FMT_USG, in, len, NULL))) { + return false; + } + + gcry_mpi_t outmpi = gcry_mpi_snew(len * 8); + gcry_mpi_powm(outmpi, inmpi, ed, n); + + size_t out_bytes = (gcry_mpi_get_nbits(outmpi) + 7) / 8; + size_t pad = len - MIN(out_bytes, len); + unsigned char *pout = out; -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)); + for(; pad; --pad) { + *pout++ = 0; + } - gcry_mpi_t outmpi = gcry_mpi_new(len * 8); - gcry_mpi_powm(outmpi, inmpi, rsa->e, rsa->n); + bool ok = check(gcry_mpi_print(GCRYMPI_FMT_USG, pout, len, NULL, outmpi)); - check(gcry_mpi_print(GCRYMPI_FMT_USG, out,len, NULL, outmpi)); + gcry_mpi_release(outmpi); + gcry_mpi_release(inmpi); - return true; + return ok; } -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)); +bool rsa_public_encrypt(rsa_t *rsa, const void *in, size_t len, void *out) { + return rsa_powm(rsa->e, rsa->n, in, len, out); +} - gcry_mpi_t outmpi = gcry_mpi_new(len * 8); - gcry_mpi_powm(outmpi, inmpi, rsa->d, rsa->n); +bool rsa_private_decrypt(rsa_t *rsa, const void *in, size_t len, void *out) { + return rsa_powm(rsa->d, rsa->n, in, len, out); +} + +void rsa_free(rsa_t *rsa) { + if(rsa) { + if(rsa->n) { + gcry_mpi_release(rsa->n); + } - check(gcry_mpi_print(GCRYMPI_FMT_USG, out,len, NULL, outmpi)); + if(rsa->e) { + gcry_mpi_release(rsa->e); + } - return true; + if(rsa->d) { + gcry_mpi_release(rsa->d); + } + + free(rsa); + } }