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-rw-r--r--g10/ChangeLog7
-rw-r--r--g10/g10.c3
-rw-r--r--g10/main.h2
-rw-r--r--g10/options.h3
-rw-r--r--g10/seskey.c15
-rw-r--r--g10/sig-check.c19
-rw-r--r--g10/sign.c2
7 files changed, 40 insertions, 11 deletions
diff --git a/g10/ChangeLog b/g10/ChangeLog
index 51c3973d0..1989b8f29 100644
--- a/g10/ChangeLog
+++ b/g10/ChangeLog
@@ -1,3 +1,10 @@
+Mon Jun 5 23:41:54 CEST 2000 Werner Koch <[email protected]>
+
+ * seskey.c (do_encode_md, encode_md_value): Add new arg v3compathack to work
+ around a bug in old versions.
+ * sig-check.c (do_check): use the aboved workaround when enabled.
+ * g10.c: New option --emulate-md-decode-bug
+
Mon Jun 5 12:37:43 CEST 2000 Werner Koch <[email protected]>
* build-packet.c (do_mdc): New.
diff --git a/g10/g10.c b/g10/g10.c
index cf2bfd64e..ea7f8aaea 100644
--- a/g10/g10.c
+++ b/g10/g10.c
@@ -187,6 +187,7 @@ enum cmd_and_opt_values { aNull = 0,
oIgnoreTimeConflict,
oNoRandomSeedFile,
oEmu3DESS2KBug, /* will be removed in 1.1 */
+ oEmuMDEncodeBug,
aTest };
@@ -367,6 +368,7 @@ static ARGPARSE_OPTS opts[] = {
{ oIgnoreTimeConflict, "ignore-time-conflict", 0, "@" },
{ oNoRandomSeedFile, "no-random-seed-file", 0, "@" },
{ oEmu3DESS2KBug, "emulate-3des-s2k-bug", 0, "@"},
+ { oEmuMDEncodeBug, "emulate-md-encode-bug", 0, "@"},
{0} };
@@ -843,6 +845,7 @@ main( int argc, char **argv )
break;
case oEmuChecksumBug: opt.emulate_bugs |= EMUBUG_GPGCHKSUM; break;
case oEmu3DESS2KBug: opt.emulate_bugs |= EMUBUG_3DESS2K; break;
+ case oEmuMDEncodeBug: opt.emulate_bugs |= EMUBUG_MDENCODE; break;
case oCompressSigs: opt.compress_sigs = 1; break;
case oRunAsShmCP:
#ifndef USE_SHM_COPROCESSING
diff --git a/g10/main.h b/g10/main.h
index 9ec141ebc..54e68db18 100644
--- a/g10/main.h
+++ b/g10/main.h
@@ -109,7 +109,7 @@ void try_make_homedir( const char *fname );
void make_session_key( DEK *dek );
MPI encode_session_key( DEK *dek, unsigned nbits );
MPI encode_md_value( int pubkey_algo, MD_HANDLE md,
- int hash_algo, unsigned nbits );
+ int hash_algo, unsigned nbits, int v3compathack );
/*-- comment.c --*/
KBNODE make_comment_node( const char *s );
diff --git a/g10/options.h b/g10/options.h
index f2090a2f0..f5657f70f 100644
--- a/g10/options.h
+++ b/g10/options.h
@@ -66,7 +66,7 @@ struct {
int rfc1991;
int rfc2440;
int pgp2_workarounds;
- unsigned emulate_bugs; /* bug emulation flags EMUBUG_xxxx */
+ unsigned int emulate_bugs; /* bug emulation flags EMUBUG_xxxx */
int shm_coprocess;
const char *set_filename;
const char *comment_string;
@@ -95,6 +95,7 @@ struct {
#define EMUBUG_GPGCHKSUM 1
#define EMUBUG_3DESS2K 2
+#define EMUBUG_MDENCODE 4
#define DBG_PACKET_VALUE 1 /* debug packet reading/writing */
#define DBG_MPI_VALUE 2 /* debug mpi details */
diff --git a/g10/seskey.c b/g10/seskey.c
index d0fe5f9bf..1ccead716 100644
--- a/g10/seskey.c
+++ b/g10/seskey.c
@@ -142,7 +142,7 @@ encode_session_key( DEK *dek, unsigned nbits )
static MPI
do_encode_md( MD_HANDLE md, int algo, size_t len, unsigned nbits,
- const byte *asn, size_t asnlen )
+ const byte *asn, size_t asnlen, int v3compathack )
{
int nframe = (nbits+7) / 8;
byte *frame;
@@ -162,7 +162,7 @@ do_encode_md( MD_HANDLE md, int algo, size_t len, unsigned nbits,
frame = md_is_secure(md)? m_alloc_secure( nframe ) : m_alloc( nframe );
n = 0;
frame[n++] = 0;
- frame[n++] = algo;
+ frame[n++] = v3compathack? algo : 1; /* block type */
i = nframe - len - asnlen -3 ;
assert( i > 1 );
memset( frame+n, 0xff, i ); n += i;
@@ -179,8 +179,15 @@ do_encode_md( MD_HANDLE md, int algo, size_t len, unsigned nbits,
}
+/****************
+ * Encode a message digest into an MPI.
+ * v3compathack is used to work around a bug in old GnuPG versions
+ * which did put the algo identifier inseatd of the block type 1 into
+ * the encoded value. setting this vare force the old behaviour.
+ */
MPI
-encode_md_value( int pubkey_algo, MD_HANDLE md, int hash_algo, unsigned nbits )
+encode_md_value( int pubkey_algo, MD_HANDLE md, int hash_algo,
+ unsigned nbits, int v3compathack )
{
int algo = hash_algo? hash_algo : md_get_algo(md);
const byte *asn;
@@ -197,7 +204,7 @@ encode_md_value( int pubkey_algo, MD_HANDLE md, int hash_algo, unsigned nbits )
}
else {
asn = md_asn_oid( algo, &asnlen, &mdlen );
- frame = do_encode_md( md, algo, mdlen, nbits, asn, asnlen );
+ frame = do_encode_md( md, algo, mdlen, nbits, asn, asnlen, v3compathack);
}
return frame;
}
diff --git a/g10/sig-check.c b/g10/sig-check.c
index 6c51cc89f..1a7e8664e 100644
--- a/g10/sig-check.c
+++ b/g10/sig-check.c
@@ -374,13 +374,24 @@ do_check( PKT_public_key *pk, PKT_signature *sig, MD_HANDLE digest,
md_final( digest );
result = encode_md_value( pk->pubkey_algo, digest, sig->digest_algo,
- mpi_get_nbits(pk->pkey[0]));
-
+ mpi_get_nbits(pk->pkey[0]), (sig->version < 4) );
ctx.sig = sig;
ctx.md = digest;
rc = pubkey_verify( pk->pubkey_algo, result, sig->data, pk->pkey,
cmp_help, &ctx );
mpi_free( result );
+ if( (opt.emulate_bugs & EMUBUG_MDENCODE)
+ && rc == G10ERR_BAD_SIGN && is_ELGAMAL(pk->pubkey_algo) ) {
+ /* In this case we try again because old GnuPG versions didn't encode
+ * the hash right. There is no problem with DSA here */
+ result = encode_md_value( pk->pubkey_algo, digest, sig->digest_algo,
+ mpi_get_nbits(pk->pkey[0]), (sig->version < 4) );
+ ctx.sig = sig;
+ ctx.md = digest;
+ rc = pubkey_verify( pk->pubkey_algo, result, sig->data, pk->pkey,
+ cmp_help, &ctx );
+ }
+
if( !rc && sig->flags.unknown_critical ) {
log_info(_("assuming bad signature due to an unknown critical bit\n"));
rc = G10ERR_BAD_SIGN;
@@ -518,7 +529,6 @@ check_key_signature2( KBNODE root, KBNODE node, int *is_selfsig,
keyid_from_pk( pk, keyid );
md = md_open( algo, 0 );
- md_start_debug( md, "rsa" );
hash_public_key( md, pk );
hash_uid_node( unode, md, sig );
if( keyid[0] == sig->keyid[0] && keyid[1] == sig->keyid[1] ) {
@@ -526,8 +536,9 @@ check_key_signature2( KBNODE root, KBNODE node, int *is_selfsig,
*is_selfsig = 1;
rc = do_check( pk, sig, md, r_expired );
}
- else
+ else {
rc = do_signature_check( sig, md, r_expiredate, r_expired );
+ }
md_close(md);
}
else {
diff --git a/g10/sign.c b/g10/sign.c
index e4b1b8f4e..6b6d5c5d0 100644
--- a/g10/sign.c
+++ b/g10/sign.c
@@ -128,7 +128,7 @@ do_sign( PKT_secret_key *sk, PKT_signature *sig,
sig->digest_start[0] = dp[0];
sig->digest_start[1] = dp[1];
frame = encode_md_value( sk->pubkey_algo, md,
- digest_algo, mpi_get_nbits(sk->skey[0]));
+ digest_algo, mpi_get_nbits(sk->skey[0]), 0 );
rc = pubkey_sign( sk->pubkey_algo, sig->data, frame, sk->skey );
mpi_free(frame);
if( rc )
generated by cgit v1.2.3 (git 2.25.1) at 2025-06-18 16:28:44 +0000