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gpg: Consider that gcry_mpi_get_opaque may return NULL.

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* g10/seckey-cert.c (do_check): Handle a NULL opaque MPI.
--

This patch extends b2d9d10 for secret keys.  The problem is that we
changed the semantics so that opaque MPIs may be NULL with a bit
length.  This patch is not required in GnuPG 2 because we do not use
secret keys there.

Signed-off-by: Werner Koch <wk@gnupg.org>
This commit is contained in:
Werner Koch 2015-06-02 17:41:30 +02:00
parent b2d9d105f7
commit 8a2134b8d5
No known key found for this signature in database
GPG key ID: E3FDFF218E45B72B
1 changed files with 34 additions and 25 deletions
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59
g10/seckey-cert.c
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@ -40,7 +40,6 @@ do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
int *canceled ) int *canceled )
{ {
gpg_error_t err; gpg_error_t err;
byte *buffer;
u16 csum=0; u16 csum=0;
int i, res; int i, res;
size_t nbytes; size_t nbytes;
@ -116,10 +115,13 @@ do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
p = gcry_mpi_get_opaque ( sk->skey[i], &ndatabits ); p = gcry_mpi_get_opaque ( sk->skey[i], &ndatabits );
ndata = (ndatabits+7)/8; ndata = (ndatabits+7)/8;
if ( ndata > 1 ) if ( ndata > 1 && p )
csumc = p[ndata-2] << 8 | p[ndata-1]; csumc = p[ndata-2] << 8 | p[ndata-1];
data = xmalloc_secure ( ndata ); data = xmalloc_secure ( ndata );
gcry_cipher_decrypt ( cipher_hd, data, ndata, p, ndata ); if (p)
gcry_cipher_decrypt ( cipher_hd, data, ndata, p, ndata );
else
memset (data, 0, ndata);
gcry_mpi_release (sk->skey[i]); sk->skey[i] = NULL ; gcry_mpi_release (sk->skey[i]); sk->skey[i] = NULL ;
p = data; p = data;
@ -129,7 +131,7 @@ do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
attack */ attack */
sk->csum = 0; sk->csum = 0;
csum = 1; csum = 1;
if( ndata < 20 ) if( ndata < 20 )
log_error("not enough bytes for SHA-1 checksum\n"); log_error("not enough bytes for SHA-1 checksum\n");
else { else {
gcry_md_hd_t h; gcry_md_hd_t h;
@ -139,7 +141,7 @@ do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
gcry_md_write (h, data, ndata - 20); gcry_md_write (h, data, ndata - 20);
gcry_md_final (h); gcry_md_final (h);
if (!memcmp (gcry_md_read (h, DIGEST_ALGO_SHA1), if (!memcmp (gcry_md_read (h, DIGEST_ALGO_SHA1),
data + ndata - 20, 20) ) data + ndata - 20, 20) )
{ {
/* Digest does match. We have to keep the old /* Digest does match. We have to keep the old
style checksum in sk->csum, so that the style checksum in sk->csum, so that the
@ -147,7 +149,7 @@ do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
This test gets used when we are adding new This test gets used when we are adding new
keys. */ keys. */
sk->csum = csum = checksum (data, ndata-20); sk->csum = csum = checksum (data, ndata-20);
} }
gcry_md_close (h); gcry_md_close (h);
} }
} }
@ -197,21 +199,28 @@ do_check( PKT_secret_key *sk, const char *tryagain_text, int mode,
assert (gcry_mpi_get_flag (sk->skey[i], GCRYMPI_FLAG_OPAQUE)); assert (gcry_mpi_get_flag (sk->skey[i], GCRYMPI_FLAG_OPAQUE));
p = gcry_mpi_get_opaque (sk->skey[i], &ndatabits); p = gcry_mpi_get_opaque (sk->skey[i], &ndatabits);
ndata = (ndatabits+7)/8; if (!p)
assert (ndata >= 2); err = -1;
assert (ndata == ((p[0] << 8 | p[1]) + 7)/8 + 2); else
buffer = xmalloc_secure (ndata); {
gcry_cipher_sync (cipher_hd); byte *buffer;
buffer[0] = p[0];
buffer[1] = p[1];
gcry_cipher_decrypt (cipher_hd, buffer+2, ndata-2,
p+2, ndata-2);
csum += checksum (buffer, ndata);
gcry_mpi_release (sk->skey[i]);
err = gcry_mpi_scan( &sk->skey[i], GCRYMPI_FMT_PGP, ndata = (ndatabits+7)/8;
buffer, ndata, &ndata ); assert (ndata >= 2);
xfree (buffer); assert (ndata == ((p[0] << 8 | p[1]) + 7)/8 + 2);
buffer = xmalloc_secure (ndata);
gcry_cipher_sync (cipher_hd);
buffer[0] = p[0];
buffer[1] = p[1];
gcry_cipher_decrypt (cipher_hd, buffer+2, ndata-2,
p+2, ndata-2);
csum += checksum (buffer, ndata);
gcry_mpi_release (sk->skey[i]);
err = gcry_mpi_scan( &sk->skey[i], GCRYMPI_FMT_PGP,
buffer, ndata, &ndata );
xfree (buffer);
}
if (err) if (err)
{ {
/* Checksum was okay, but not correctly /* Checksum was okay, but not correctly
@ -346,11 +355,11 @@ protect_secret_key( PKT_secret_key *sk, DEK *dek )
if ( openpgp_cipher_test_algo ( sk->protect.algo ) ) { if ( openpgp_cipher_test_algo ( sk->protect.algo ) ) {
/* Unsupport protection algorithm. */ /* Unsupport protection algorithm. */
rc = gpg_error (GPG_ERR_CIPHER_ALGO); rc = gpg_error (GPG_ERR_CIPHER_ALGO);
} }
else { else {
print_cipher_algo_note( sk->protect.algo ); print_cipher_algo_note( sk->protect.algo );
if ( openpgp_cipher_open (&cipher_hd, sk->protect.algo, if ( openpgp_cipher_open (&cipher_hd, sk->protect.algo,
GCRY_CIPHER_MODE_CFB, GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE (GCRY_CIPHER_SECURE
@ -399,10 +408,10 @@ protect_secret_key( PKT_secret_key *sk, DEK *dek )
p += narr[j]; p += narr[j];
xfree(bufarr[j]); xfree(bufarr[j]);
} }
if (opt.simple_sk_checksum) { if (opt.simple_sk_checksum) {
log_info (_("generating the deprecated 16-bit checksum" log_info (_("generating the deprecated 16-bit checksum"
" for secret key protection\n")); " for secret key protection\n"));
csum = checksum( data, ndata-2); csum = checksum( data, ndata-2);
sk->csum = csum; sk->csum = csum;
*p++ = csum >> 8; *p++ = csum >> 8;
@ -458,7 +467,7 @@ protect_secret_key( PKT_secret_key *sk, DEK *dek )
gcry_cipher_encrypt (cipher_hd, data+2, nbytes, gcry_cipher_encrypt (cipher_hd, data+2, nbytes,
buffer, nbytes); buffer, nbytes);
xfree( buffer ); xfree( buffer );
gcry_mpi_release (sk->skey[i]); gcry_mpi_release (sk->skey[i]);
sk->skey[i] = gcry_mpi_set_opaque (NULL, sk->skey[i] = gcry_mpi_set_opaque (NULL,
data, (nbytes+2)*8 ); data, (nbytes+2)*8 );