~ubuntu-branches/ubuntu/feisty/clamav/feisty-backports

#define CLI_NSTR "118640995551645342603070001658453189751527774412027743746599405743243142607464144767361060640655844749760788890022283424922762488917565551002467771109669598189410434699034532232228621591089508178591428456220796841621637175567590476666928698770143328137383952820383197532047771780196576957695822641224262693037"

#define CLI_ESTR "100001027"

#define CLI_NSTRPSS "14783905874077467090262228516557917570254599638376203532031989214105552847269687489771975792123442185817287694951949800908791527542017115600501303394778618535864845235700041590056318230102449612217458549016089313306591388590790796515819654102320725712300822356348724011232654837503241736177907784198700834440681124727060540035754699658105895050096576226753008596881698828185652424901921668758326578462003247906470982092298106789657211905488986281078346361469524484829559560886227198091995498440676639639830463593211386055065360288422394053998134458623712540683294034953818412458362198117811990006021989844180721010947"

#define CLI_ESTRPSS "100002053"

#define PSS_NBITS 2048

#define PSS_DIGEST_LENGTH 32

static char cli_ndecode(char value)

static unsigned char cli_ndecode(unsigned char value)

{

int i;

unsigned int i;

char ncodec[] = {

'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l',

'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',

return -1;

}

static unsigned char *cli_decodesig(const char *sig, int plainlen, mpz_t e, mpz_t n)

unsigned char *cli_decodesig(const char *sig, unsigned int plen, mpz_t e, mpz_t n)

{

int i, siglen = strlen(sig), dec;

unsigned char *decoded;

int i, slen = strlen(sig), dec;

unsigned char *plain;

mpz_t r, p, c;

mpz_init(r);

mpz_init(c);

for(i = 0; i < siglen; i++) {

for(i = 0; i < slen; i++) {

if((dec = cli_ndecode(sig[i])) < 0) {

mpz_clear(r);

mpz_clear(c);

mpz_add(c, c, r);

}

decoded = (unsigned char *) cli_calloc(plainlen + 1, sizeof(unsigned char));

if(!decoded) {

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cli_errmsg("cli_decodesig: Can't allocate memory\n");

plain = (unsigned char *) cli_calloc(plen + 1, sizeof(unsigned char));

if(!plain) {

cli_errmsg("cli_decodesig: Can't allocate memory for 'plain'\n");

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mpz_clear(r);

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mpz_clear(c);

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return NULL;

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mpz_powm(p, c, e, n); /* plain = cipher^e mod n */

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mpz_clear(c);

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for(i = plainlen - 1; i >= 0; i--) { /* reverse */

for(i = plen - 1; i >= 0; i--) { /* reverse */

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mpz_tdiv_qr_ui(p, r, p, 256);

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decoded[i] = mpz_get_ui(r);

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plain[i] = mpz_get_ui(r);

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}

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mpz_clear(p);

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mpz_clear(r);

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return decoded;

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}

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static void cli_mgf(unsigned char *in, unsigned int inlen, unsigned char *out, unsigned int outlen)

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{

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SHA256_CTX ctx;

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unsigned int i, laps;

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unsigned char cnt[4], digest[PSS_DIGEST_LENGTH];

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laps = (outlen + PSS_DIGEST_LENGTH - 1) / PSS_DIGEST_LENGTH;

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for(i = 0; i < laps; i++) {

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cnt[0] = (unsigned char) 0;

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cnt[1] = (unsigned char) 0;

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cnt[2] = (unsigned char) (i / 256);

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cnt[3] = (unsigned char) i;

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sha256_init(&ctx);

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sha256_update(&ctx, in, inlen);

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sha256_update(&ctx, cnt, sizeof(cnt));

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sha256_final(&ctx);

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sha256_digest(&ctx, digest);

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if(i != laps - 1)

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memcpy(&out[i * PSS_DIGEST_LENGTH], digest, PSS_DIGEST_LENGTH);

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else

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memcpy(&out[i * PSS_DIGEST_LENGTH], digest, outlen - i * PSS_DIGEST_LENGTH);

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}

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}

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int cli_versigpss(const unsigned char *sha256, const char *dsig)

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{

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mpz_t n, e;

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SHA256_CTX ctx;

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unsigned char *pt, digest1[PSS_DIGEST_LENGTH], digest2[PSS_DIGEST_LENGTH], *salt;

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unsigned int plen = PSS_NBITS / 8, hlen, slen, i;

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unsigned char dblock[PSS_NBITS / 8 - PSS_DIGEST_LENGTH - 1];

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unsigned char mblock[PSS_NBITS / 8 - PSS_DIGEST_LENGTH - 1];

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unsigned char fblock[8 + 2 * PSS_DIGEST_LENGTH];

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hlen = slen = PSS_DIGEST_LENGTH;

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mpz_init_set_str(n, CLI_NSTRPSS, 10);

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mpz_init_set_str(e, CLI_ESTRPSS, 10);

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if(!(pt = cli_decodesig(dsig, plen, e, n))) {

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mpz_clear(n);

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mpz_clear(e);

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return CL_EDSIG;

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}

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mpz_clear(n);

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mpz_clear(e);

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if(pt[plen - 1] != 0xbc) {

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cli_dbgmsg("cli_versigpss: Incorrect signature syntax (0xbc)\n");

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free(pt);

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return CL_EDSIG;

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}

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memcpy(mblock, pt, plen - hlen - 1);

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memcpy(digest2, &pt[plen - hlen - 1], hlen);

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free(pt);

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cli_mgf(digest2, hlen, dblock, plen - hlen - 1);

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for(i = 0; i < plen - hlen - 1; i++)

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dblock[i] ^= mblock[i];

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dblock[0] &= (0xff >> 1);

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salt = memchr(dblock, 0x01, sizeof(dblock));

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if(!salt) {

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cli_dbgmsg("cli_versigpss: Can't find salt\n");

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return CL_EDSIG;

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}

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salt++;

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if((unsigned int) (dblock + sizeof(dblock) - salt) != slen) {

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cli_dbgmsg("cli_versigpss: Bad salt size\n");

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return CL_EDSIG;

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}

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memset(fblock, 0, 8);

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memcpy(&fblock[8], sha256, hlen);

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memcpy(&fblock[8 + hlen], salt, slen);

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sha256_init(&ctx);

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sha256_update(&ctx, fblock, sizeof(fblock));

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sha256_final(&ctx);

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sha256_digest(&ctx, digest1);

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if(memcmp(digest1, digest2, hlen)) {

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cli_dbgmsg("cli_versigpss: Signature doesn't match.\n");

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return CL_EDSIG;

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}

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cli_dbgmsg("cli_versigpss: Digital signature is correct.\n");

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return CL_SUCCESS;

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return plain;

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}

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int cli_versig(const char *md5, const char *dsig)

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