security-and-privacy/gnupg
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added option export

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This commit is contained in:
Werner Koch 1998-02-13 20:58:50 +00:00
parent b9fccd69e4
commit f477447d9a
43 changed files with 734 additions and 284 deletions
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68
g10/pubkey-enc.c
View file

@ -38,8 +38,10 @@
int
get_session_key( PKT_pubkey_enc *k, DEK *dek )
{
int i, j, c, rc = 0;
MPI dek_frame = mpi_alloc_secure(40);
int rc = 0;
MPI plain_dek = NULL;
byte *frame = NULL;
unsigned n, nframe;
u16 csum, csum2;
PKT_secret_cert *skc = m_alloc_clear( sizeof *skc );
@ -58,7 +60,8 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
skey.g = skc->d.elg.g;
skey.y = skc->d.elg.y;
skey.x = skc->d.elg.x;
elg_decrypt( dek_frame, k->d.elg.a, k->d.elg.b, &skey );
plain_dek = mpi_alloc_secure( mpi_get_nlimbs(skey.p) );
elg_decrypt( plain_dek, k->d.elg.a, k->d.elg.b, &skey );
memset( &skey, 0, sizeof skey );
}
#ifdef HAVE_RSA_CIPHER
@ -74,7 +77,8 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
skey.q = skc->d.rsa.rsa_q;
skey.d = skc->d.rsa.rsa_d;
skey.u = skc->d.rsa.rsa_u;
rsa_secret( dek_frame, k->d.rsa.rsa_integer, &skey );
plain_dek = mpi_alloc_secure( mpi_get_nlimbs(skey.n) );
rsa_secret( plain_dek, k->d.rsa.rsa_integer, &skey );
memset( &skey, 0, sizeof skey );
}
#endif/*HAVE_RSA_CIPHER*/
@ -83,9 +87,10 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
goto leave;
}
free_secret_cert( skc ); skc = NULL;
frame = mpi_get_buffer( plain_dek, &nframe, NULL );
mpi_free( plain_dek ); plain_dek = NULL;
/* Now get the DEK (data encryption key) from the dek_frame
/* Now get the DEK (data encryption key) from the frame
*
* Old versions encode the DEK in in this format (msb is left):
*
@ -101,51 +106,53 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
* CSUM
*/
if( DBG_CIPHER )
log_mpidump("DEK frame:", dek_frame );
for(i=0; mpi_getbyte(dek_frame, i) != -1; i++ )
log_hexdump("DEK frame:", frame, nframe );
for(n=0; n < nframe && !frame[n]; n++ ) /* skip leading zeroes */
;
for(i--; i >= 0 && !(c=mpi_getbyte(dek_frame, i)); i--)
; /* Skip leading zeroes */
if( i < 16 )
if( n + 7 > nframe )
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
if( c == 1 && mpi_getbyte(dek_frame,0) == 2 ) {
if( frame[n] == 1 && frame[nframe-1] == 2 ) {
log_error("old encoding of DEK is not supported\n");
rc = G10ERR_CIPHER_ALGO;
goto leave;
}
if( c != 2 ) /* somethink is wrong */
if( frame[n] != 2 ) /* somethink is wrong */
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
/* look for the zero byte */
for(i--; i > 4 ; i-- )
if( !mpi_getbyte(dek_frame,i) )
break;
if( i <= 4 ) /* zero byte not found */
for(n++; n < nframe && frame[n]; n++ ) /* skip the random bytes */
;
n++; /* and the zero byte */
if( n + 4 > nframe )
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
/* next byte indicates the used cipher */
switch( mpi_getbyte(dek_frame, --i ) ) {
dek->keylen = nframe - (n+1) - 2;
dek->algo = frame[n++];
switch( dek->algo ) {
case CIPHER_ALGO_IDEA:
rc = G10ERR_NI_CIPHER;
goto leave;
case CIPHER_ALGO_BLOWFISH:
if( i != 22 ) /* length of blowfish is 20 (+2 bytes checksum) */
if( dek->keylen != 20 )
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
dek->algo = CIPHER_ALGO_BLOWFISH;
break;
case CIPHER_ALGO_BLOWFISH128:
if( i != 18 ) /* length of blowfish-128 is 16 (+2 bytes checksum) */
if( dek->keylen != 16 )
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
break;
case CIPHER_ALGO_CAST:
if( dek->keylen < 5 || dek->keylen > 16 )
{ rc = G10ERR_WRONG_SECKEY; goto leave; }
dek->algo = CIPHER_ALGO_BLOWFISH128;
break;
default:
dek->algo = 0;
rc = G10ERR_CIPHER_ALGO;
goto leave;
}
/* copy the key to DEK and compare the checksum */
csum = mpi_getbyte(dek_frame, 1) << 8;
csum |= mpi_getbyte(dek_frame, 0);
dek->keylen = i - 2;
for( i--, csum2=0, j=0; i > 1; i-- )
csum2 += dek->key[j++] = mpi_getbyte(dek_frame, i);
csum = frame[nframe-2] << 8;
csum |= frame[nframe-1];
memcpy( dek->key, frame+n, dek->keylen );
for( csum2=0, n=0; n < dek->keylen; n++ )
csum2 += dek->key[n];
if( csum != csum2 ) {
rc = G10ERR_WRONG_SECKEY;
goto leave;
@ -154,7 +161,8 @@ get_session_key( PKT_pubkey_enc *k, DEK *dek )
log_hexdump("DEK is:", dek->key, dek->keylen );
leave:
mpi_free(dek_frame);
mpi_free(plain_dek);
m_free(frame);
if( skc )
free_secret_cert( skc );
return rc;