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git://git.gnupg.org/gnupg.git
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Fix for bug 537
This commit is contained in:
Werner Koch
parent
807cb227d1
commit
4b48bcacc9
111 changed files with 3111 additions and 2145 deletions
419
g10/encr-data.c
419
g10/encr-data.c
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@ -34,16 +34,16 @@
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#include "i18n.h"
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static int mdc_decode_filter( void *opaque, int control, IOBUF a,
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byte *buf, size_t *ret_len);
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static int decode_filter( void *opaque, int control, IOBUF a,
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static int mdc_decode_filter ( void *opaque, int control, IOBUF a,
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byte *buf, size_t *ret_len);
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static int decode_filter ( void *opaque, int control, IOBUF a,
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byte *buf, size_t *ret_len);
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typedef struct
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{
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gcry_cipher_hd_t cipher_hd;
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gcry_md_hd_t mdc_hash;
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char defer[20];
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char defer[22];
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int defer_filled;
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int eof_seen;
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} decode_filter_ctx_t;
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@ -55,228 +55,271 @@ typedef struct
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int
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decrypt_data( void *procctx, PKT_encrypted *ed, DEK *dek )
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{
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decode_filter_ctx_t dfx;
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byte *p;
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int rc=0, c, i;
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byte temp[32];
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unsigned blocksize;
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unsigned nprefix;
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memset( &dfx, 0, sizeof dfx );
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if( opt.verbose && !dek->algo_info_printed ) {
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const char *s = gcry_cipher_algo_name (dek->algo);
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if (s && *s)
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log_info(_("%s encrypted data\n"), s );
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else
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log_info(_("encrypted with unknown algorithm %d\n"), dek->algo );
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dek->algo_info_printed = 1;
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decode_filter_ctx_t dfx;
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byte *p;
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int rc=0, c, i;
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byte temp[32];
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unsigned blocksize;
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unsigned nprefix;
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memset( &dfx, 0, sizeof dfx );
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if ( opt.verbose && !dek->algo_info_printed )
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{
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const char *s = gcry_cipher_algo_name (dek->algo);
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if (s && *s)
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log_info(_("%s encrypted data\n"), s );
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else
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log_info(_("encrypted with unknown algorithm %d\n"), dek->algo );
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dek->algo_info_printed = 1;
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}
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rc = openpgp_cipher_test_algo (dek->algo);
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if (rc)
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goto leave;
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blocksize = gcry_cipher_get_algo_blklen (dek->algo);
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if( !blocksize || blocksize > 16 )
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log_fatal("unsupported blocksize %u\n", blocksize );
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nprefix = blocksize;
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if( ed->len && ed->len < (nprefix+2) )
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BUG();
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rc = openpgp_cipher_test_algo (dek->algo);
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if (rc)
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goto leave;
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blocksize = gcry_cipher_get_algo_blklen (dek->algo);
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if ( !blocksize || blocksize > 16 )
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log_fatal("unsupported blocksize %u\n", blocksize );
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nprefix = blocksize;
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if ( ed->len && ed->len < (nprefix+2) )
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BUG();
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if( ed->mdc_method ) {
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if (gcry_md_open (&dfx.mdc_hash, ed->mdc_method, 0 ))
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BUG ();
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if ( DBG_HASHING )
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gcry_md_start_debug (dfx.mdc_hash, "checkmdc");
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if ( ed->mdc_method )
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{
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if (gcry_md_open (&dfx.mdc_hash, ed->mdc_method, 0 ))
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BUG ();
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if ( DBG_HASHING )
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gcry_md_start_debug (dfx.mdc_hash, "checkmdc");
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}
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rc = gcry_cipher_open (&dfx.cipher_hd, dek->algo,
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GCRY_CIPHER_MODE_CFB,
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(GCRY_CIPHER_SECURE
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| ((ed->mdc_method || dek->algo >= 100)?
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0 : GCRY_CIPHER_ENABLE_SYNC)));
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if (rc)
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{
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/* We should never get an error here cause we already checked
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* that the algorithm is available. */
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BUG();
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}
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/* log_hexdump( "thekey", dek->key, dek->keylen );*/
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rc = gcry_cipher_setkey (dfx.cipher_hd, dek->key, dek->keylen);
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if ( gpg_err_code (rc) == GPG_ERR_WEAK_KEY )
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{
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log_info(_("WARNING: message was encrypted with"
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" a weak key in the symmetric cipher.\n"));
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rc=0;
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}
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else if( rc )
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{
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log_error("key setup failed: %s\n", g10_errstr(rc) );
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goto leave;
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}
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if (!ed->buf) {
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log_error(_("problem handling encrypted packet\n"));
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goto leave;
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rc = gcry_cipher_open (&dfx.cipher_hd, dek->algo,
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GCRY_CIPHER_MODE_CFB,
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(GCRY_CIPHER_SECURE
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| ((ed->mdc_method || dek->algo >= 100)?
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0 : GCRY_CIPHER_ENABLE_SYNC)));
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if (rc)
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{
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/* We should never get an error here cause we already checked
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* that the algorithm is available. */
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BUG();
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}
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gcry_cipher_setiv (dfx.cipher_hd, NULL, 0);
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if( ed->len ) {
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for(i=0; i < (nprefix+2) && ed->len; i++, ed->len-- ) {
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if( (c=iobuf_get(ed->buf)) == -1 )
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break;
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else
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temp[i] = c;
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}
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/* log_hexdump( "thekey", dek->key, dek->keylen );*/
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rc = gcry_cipher_setkey (dfx.cipher_hd, dek->key, dek->keylen);
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if ( gpg_err_code (rc) == GPG_ERR_WEAK_KEY )
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{
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log_info(_("WARNING: message was encrypted with"
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" a weak key in the symmetric cipher.\n"));
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rc=0;
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}
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else {
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for(i=0; i < (nprefix+2); i++ )
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if( (c=iobuf_get(ed->buf)) == -1 )
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break;
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else
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temp[i] = c;
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else if( rc )
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{
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log_error("key setup failed: %s\n", g10_errstr(rc) );
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goto leave;
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}
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gcry_cipher_decrypt (dfx.cipher_hd, temp, nprefix+2, NULL, 0);
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gcry_cipher_sync (dfx.cipher_hd);
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p = temp;
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/* log_hexdump( "prefix", temp, nprefix+2 ); */
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if(dek->symmetric
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&& (p[nprefix-2] != p[nprefix] || p[nprefix-1] != p[nprefix+1]) )
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{
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rc = GPG_ERR_BAD_KEY;
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goto leave;
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}
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if( dfx.mdc_hash )
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gcry_md_write (dfx.mdc_hash, temp, nprefix+2);
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if( ed->mdc_method )
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iobuf_push_filter( ed->buf, mdc_decode_filter, &dfx );
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else
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iobuf_push_filter( ed->buf, decode_filter, &dfx );
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proc_packets( procctx, ed->buf );
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ed->buf = NULL;
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if( ed->mdc_method && dfx.eof_seen == 2 )
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rc = gpg_error (GPG_ERR_INV_PACKET);
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else if( ed->mdc_method ) { /* check the mdc */
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int datalen = gcry_md_get_algo_dlen (ed->mdc_method);
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gcry_cipher_decrypt (dfx.cipher_hd, dfx.defer, 20, NULL, 0);
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gcry_md_final (dfx.mdc_hash);
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if (datalen != 20
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|| memcmp (gcry_md_read( dfx.mdc_hash, 0 ), dfx.defer, datalen) )
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rc = gpg_error (GPG_ERR_BAD_SIGNATURE);
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/*log_hexdump("MDC calculated:", md_read( dfx.mdc_hash, 0), datalen);*/
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/*log_hexdump("MDC message :", dfx.defer, 20);*/
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if (!ed->buf)
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{
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log_error(_("problem handling encrypted packet\n"));
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goto leave;
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}
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leave:
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gcry_cipher_close (dfx.cipher_hd);
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gcry_md_close (dfx.mdc_hash);
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return rc;
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gcry_cipher_setiv (dfx.cipher_hd, NULL, 0);
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if ( ed->len )
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{
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for (i=0; i < (nprefix+2) && ed->len; i++, ed->len-- )
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{
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if ( (c=iobuf_get(ed->buf)) == -1 )
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break;
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else
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temp[i] = c;
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}
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}
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else
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{
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for (i=0; i < (nprefix+2); i++ )
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if ( (c=iobuf_get(ed->buf)) == -1 )
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break;
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else
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temp[i] = c;
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}
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gcry_cipher_decrypt (dfx.cipher_hd, temp, nprefix+2, NULL, 0);
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gcry_cipher_sync (dfx.cipher_hd);
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p = temp;
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/* log_hexdump( "prefix", temp, nprefix+2 ); */
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if (dek->symmetric
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&& (p[nprefix-2] != p[nprefix] || p[nprefix-1] != p[nprefix+1]) )
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{
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rc = gpg_error (GPG_ERR_BAD_KEY);
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goto leave;
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}
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if ( dfx.mdc_hash )
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gcry_md_write (dfx.mdc_hash, temp, nprefix+2);
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if ( ed->mdc_method )
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iobuf_push_filter( ed->buf, mdc_decode_filter, &dfx );
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else
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iobuf_push_filter( ed->buf, decode_filter, &dfx );
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proc_packets ( procctx, ed->buf );
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ed->buf = NULL;
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if ( ed->mdc_method && dfx.eof_seen == 2 )
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rc = gpg_error (GPG_ERR_INV_PACKET);
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else if ( ed->mdc_method )
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{
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/* We used to let parse-packet.c handle the MDC packet but this
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turned out to be a problem with compressed packets: With old
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style packets there is no length information available and
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the decompressor uses an implicit end. However we can't know
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this implicit end beforehand (:-) and thus may feed the
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decompressor with more bytes than actually needed. It would
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be possible to unread the extra bytes but due to our weird
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iobuf system any unread is non reliable due to filters
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already popped off. The easy and sane solution is to care
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about the MDC packet only here and never pass it to the
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packet parser. Fortunatley the OpenPGP spec requires a
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strict format for the MDC packet so that we know that 22
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bytes are appended. */
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int datalen = gcry_md_get_algo_dlen (ed->mdc_method);
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gcry_cipher_decrypt (dfx.cipher_hd, dfx.defer, 22, NULL, 0);
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gcry_md_write (dfx.mdc_hash, dfx.defer, 2);
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gcry_md_final (dfx.mdc_hash);
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if (dfx.defer[0] != '\xd3' || dfx.defer[1] != '\x14' )
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{
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log_error("mdc_packet with invalid encoding\n");
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rc = gpg_error (GPG_ERR_INV_PACKET);
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}
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else if (datalen != 20
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|| memcmp (gcry_md_read (dfx.mdc_hash, 0),dfx.defer+2,datalen))
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rc = gpg_error (GPG_ERR_BAD_SIGNATURE);
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/* log_printhex("MDC message:", dfx.defer, 22); */
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/* log_printhex("MDC calc:", gcry_md_read (dfx.mdc_hash,0), datalen); */
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}
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leave:
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gcry_cipher_close (dfx.cipher_hd);
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gcry_md_close (dfx.mdc_hash);
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return rc;
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}
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/* I think we should merge this with cipher_filter */
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static int
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mdc_decode_filter( void *opaque, int control, IOBUF a,
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byte *buf, size_t *ret_len)
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mdc_decode_filter (void *opaque, int control, IOBUF a,
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byte *buf, size_t *ret_len)
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{
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decode_filter_ctx_t *dfx = opaque;
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size_t n, size = *ret_len;
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int rc = 0;
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int c;
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if( control == IOBUFCTRL_UNDERFLOW && dfx->eof_seen ) {
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*ret_len = 0;
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rc = -1;
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decode_filter_ctx_t *dfx = opaque;
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size_t n, size = *ret_len;
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int rc = 0;
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int c;
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if ( control == IOBUFCTRL_UNDERFLOW && dfx->eof_seen )
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{
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*ret_len = 0;
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rc = -1;
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}
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else if( control == IOBUFCTRL_UNDERFLOW ) {
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assert(a);
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assert( size > 40 );
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/* get at least 20 bytes and put it somewhere ahead in the buffer */
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for(n=20; n < 40 ; n++ ) {
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if( (c = iobuf_get(a)) == -1 )
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break;
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buf[n] = c;
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else if( control == IOBUFCTRL_UNDERFLOW )
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{
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assert(a);
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assert( size > 44 );
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/* Get at least 22 bytes and put it somewhere ahead in the buffer. */
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for(n=22; n < 44 ; n++ )
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{
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if( (c = iobuf_get(a)) == -1 )
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break;
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buf[n] = c;
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}
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if( n == 40 ) {
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/* we have enough stuff - flush the deferred stuff */
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/* (we have asserted that the buffer is large enough) */
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if( !dfx->defer_filled ) { /* the first time */
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memcpy(buf, buf+20, 20 );
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n = 20;
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if ( n == 44 )
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{
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/* We have enough stuff - flush the deferred stuff. */
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/* (we asserted that the buffer is large enough) */
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if ( !dfx->defer_filled ) /* First time. */
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{
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memcpy (buf, buf+22, 22 );
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n = 22;
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}
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else {
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memcpy(buf, dfx->defer, 20 );
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else
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{
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memcpy (buf, dfx->defer, 22 );
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}
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/* now fill up */
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for(; n < size; n++ ) {
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if( (c = iobuf_get(a)) == -1 )
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break;
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buf[n] = c;
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/* Now fill up. */
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for (; n < size; n++ )
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{
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if ( (c = iobuf_get(a)) == -1 )
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break;
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buf[n] = c;
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}
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/* move the last 20 bytes back to the defer buffer */
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/* (okay, we are wasting 20 bytes of supplied buffer) */
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n -= 20;
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memcpy( dfx->defer, buf+n, 20 );
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dfx->defer_filled = 1;
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/* Move the last 22 bytes back to the defer buffer. */
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/* (right, we are wasting 22 bytes of the supplied buffer.) */
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n -= 22;
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memcpy (dfx->defer, buf+n, 22 );
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dfx->defer_filled = 1;
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}
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else if( !dfx->defer_filled ) { /* eof seen buf empty defer */
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/* this is bad because there is an incomplete hash */
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n -= 20;
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memcpy(buf, buf+20, n );
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dfx->eof_seen = 2; /* eof with incomplete hash */
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else if ( !dfx->defer_filled ) /* EOF seen but empty defer buffer. */
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{
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/* This is bad because it means an incomplete hash. */
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n -= 22;
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memcpy (buf, buf+22, n );
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dfx->eof_seen = 2; /* EOF with incomplete hash. */
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}
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else { /* eof seen */
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memcpy(buf, dfx->defer, 20 );
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n -= 20;
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memcpy( dfx->defer, buf+n, 20 );
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dfx->eof_seen = 1; /* normal eof */
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else /* EOF seen (i.e. read less than 22 bytes). */
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{
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memcpy (buf, dfx->defer, 22 );
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n -= 22;
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memcpy (dfx->defer, buf+n, 22 );
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dfx->eof_seen = 1; /* Normal EOF. */
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}
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if( n ) {
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gcry_cipher_decrypt (dfx->cipher_hd, buf, n, NULL, 0);
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gcry_md_write (dfx->mdc_hash, buf, n);
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if ( n )
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{
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gcry_cipher_decrypt (dfx->cipher_hd, buf, n, NULL, 0);
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gcry_md_write (dfx->mdc_hash, buf, n);
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}
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else {
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assert( dfx->eof_seen );
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rc = -1; /* eof */
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else
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{
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assert ( dfx->eof_seen );
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rc = -1; /* eof */
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}
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*ret_len = n;
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*ret_len = n;
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}
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else if( control == IOBUFCTRL_DESC ) {
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*(char**)buf = "mdc_decode_filter";
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else if ( control == IOBUFCTRL_DESC )
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{
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*(char**)buf = "mdc_decode_filter";
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}
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return rc;
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return rc;
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}
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|
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static int
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decode_filter( void *opaque, int control, IOBUF a, byte *buf, size_t *ret_len)
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{
|
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decode_filter_ctx_t *fc = opaque;
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size_t n, size = *ret_len;
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int rc = 0;
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if( control == IOBUFCTRL_UNDERFLOW ) {
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assert(a);
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n = iobuf_read( a, buf, size );
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if( n == -1 ) n = 0;
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if( n )
|
||||
gcry_cipher_decrypt (fc->cipher_hd, buf, n, NULL, 0);
|
||||
else
|
||||
rc = -1; /* eof */
|
||||
*ret_len = n;
|
||||
decode_filter_ctx_t *fc = opaque;
|
||||
size_t n, size = *ret_len;
|
||||
int rc = 0;
|
||||
|
||||
if ( control == IOBUFCTRL_UNDERFLOW )
|
||||
{
|
||||
assert(a);
|
||||
n = iobuf_read ( a, buf, size );
|
||||
if ( n == -1 )
|
||||
n = 0;
|
||||
if ( n )
|
||||
gcry_cipher_decrypt (fc->cipher_hd, buf, n, NULL, 0);
|
||||
else
|
||||
rc = -1; /* EOF */
|
||||
*ret_len = n;
|
||||
}
|
||||
else if( control == IOBUFCTRL_DESC ) {
|
||||
*(char**)buf = "decode_filter";
|
||||
else if ( control == IOBUFCTRL_DESC )
|
||||
{
|
||||
*(char**)buf = "decode_filter";
|
||||
}
|
||||
return rc;
|
||||
return rc;
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue