security-and-privacy/gnupg
security-and-privacy/gnupg
1
0
Fork 0
mirror of git://git.gnupg.org/gnupg.git synced 2024-12-22 10:19:57 +01:00
Code Activity

Disable the "quick check" bytes for PK decryptions. This is in

Browse Source 
regards to the Mister and Zuccherato attack on OpenPGP CFB mode.
This commit is contained in:
David Shaw 2005-02-10 04:11:35 +00:00
parent 658d1e7302
commit 4df22ba030
5 changed files with 25 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
g10/ChangeLog
View File

@ -1,3 +1,12 @@
2005-02-09 David Shaw <dshaw@jabberwocky.com>
* mainproc.c (proc_symkey_enc): Set a flag to indicate that a
particular session key came from a passphrase and not a PK.
* encr-data.c (decrypt_data): Use it here to turn off the "quick
check" bytes for PK decryptions. This is in regards to the Mister
and Zuccherato attack on OpenPGP CFB mode.
2004-11-29 David Shaw <dshaw@jabberwocky.com> 2004-11-29 David Shaw <dshaw@jabberwocky.com>
* getkey.c (parse_key_usage): New function to parse out key usage * getkey.c (parse_key_usage): New function to parse out key usage

8
g10/encr-data.c
View File

@ -1,5 +1,5 @@
/* encr-data.c - process an encrypted data packet /* encr-data.c - process an encrypted data packet
* Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc. * Copyright (C) 1998, 1999, 2000, 2001, 2005 Free Software Foundation, Inc.
* *
* This file is part of GnuPG. * This file is part of GnuPG.
* *
@ -120,10 +120,12 @@ decrypt_data( void *procctx, PKT_encrypted *ed, DEK *dek )
cipher_sync( dfx.cipher_hd ); cipher_sync( dfx.cipher_hd );
p = temp; p = temp;
/* log_hexdump( "prefix", temp, nprefix+2 ); */ /* log_hexdump( "prefix", temp, nprefix+2 ); */
if( p[nprefix-2] != p[nprefix] || p[nprefix-1] != p[nprefix+1] ) { if( dek->symmetric
&& (p[nprefix-2] != p[nprefix] || p[nprefix-1] != p[nprefix+1]) )
{
rc = G10ERR_BAD_KEY; rc = G10ERR_BAD_KEY;
goto leave; goto leave;
} }
if( dfx.mdc_hash ) if( dfx.mdc_hash )
md_write( dfx.mdc_hash, temp, nprefix+2 ); md_write( dfx.mdc_hash, temp, nprefix+2 );

6
g10/mainproc.c
View File

@ -1,6 +1,6 @@
/* mainproc.c - handle packets /* mainproc.c - handle packets
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
* 2004 Free Software Foundation, Inc. * 2005 Free Software Foundation, Inc.
* *
* This file is part of GnuPG. * This file is part of GnuPG.
* *
@ -317,6 +317,8 @@ proc_symkey_enc( CTX c, PACKET *pkt )
c->dek = passphrase_to_dek( NULL, 0, algo, &enc->s2k, 0, NULL, NULL ); c->dek = passphrase_to_dek( NULL, 0, algo, &enc->s2k, 0, NULL, NULL );
if(c->dek) if(c->dek)
{ {
c->dek->symmetric=1;
/* FIXME: This doesn't work perfectly if a symmetric key /* FIXME: This doesn't work perfectly if a symmetric key
comes before a public key in the message - if the user comes before a public key in the message - if the user
doesn't know the passphrase, then there is a chance doesn't know the passphrase, then there is a chance

4
include/ChangeLog
View File

@ -1,3 +1,7 @@
2005-02-09 David Shaw <dshaw@jabberwocky.com>
* cipher.h: Add a flag for a symmetric DEK.
2004-11-29 David Shaw <dshaw@jabberwocky.com> 2004-11-29 David Shaw <dshaw@jabberwocky.com>
* cipher.h: Add PUBKEY_USAGE_UNKNOWN. * cipher.h: Add PUBKEY_USAGE_UNKNOWN.

4
include/cipher.h
View File

@ -1,5 +1,6 @@
/* cipher.h /* cipher.h
* Copyright (C) 1998, 1999, 2000, 2001, 2003 Free Software Foundation, Inc. * Copyright (C) 1998, 1999, 2000, 2001, 2003,
* 2005 Free Software Foundation, Inc.
* *
* This file is part of GNUPG. * This file is part of GNUPG.
* *
@ -76,6 +77,7 @@ typedef struct {
int keylen; int keylen;
int algo_info_printed; int algo_info_printed;
int use_mdc; int use_mdc;
int symmetric;
byte key[32]; /* this is the largest used keylen (256 bit) */ byte key[32]; /* this is the largest used keylen (256 bit) */
} DEK; } DEK;