261 lines
7.3 KiB
Diff
261 lines
7.3 KiB
Diff
This is a patch against GnuPG 2.0.1. Change the directory to g10/ and
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apply this patch.
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2006-12-02 Werner Koch <wk@g10code.com>
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* encr-data.c: Allocate DFX context on the heap and not on the
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stack. Changes at several places. Fixes CVE-2006-6235.
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Index: encr-data.c
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===================================================================
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--- encr-data.c (revision 4352)
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+++ encr-data.c (working copy)
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@@ -39,16 +39,37 @@
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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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+typedef struct decode_filter_context_s
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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[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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+ int refcount;
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+} *decode_filter_ctx_t;
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+/* Helper to release the decode context. */
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+static void
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+release_dfx_context (decode_filter_ctx_t dfx)
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+{
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+ if (!dfx)
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+ return;
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+
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+ assert (dfx->refcount);
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+ if ( !--dfx->refcount )
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+ {
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+ gcry_cipher_close (dfx->cipher_hd);
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+ dfx->cipher_hd = NULL;
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+ gcry_md_close (dfx->mdc_hash);
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+ dfx->mdc_hash = NULL;
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+ xfree (dfx);
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+ }
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+}
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+
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+
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+
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/****************
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* Decrypt the data, specified by ED with the key DEK.
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*/
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@@ -62,7 +83,11 @@
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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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+ dfx = xtrycalloc (1, sizeof *dfx);
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+ if (!dfx)
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+ return gpg_error_from_syserror ();
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+ dfx->refcount = 1;
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+
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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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@@ -77,20 +102,20 @@
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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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+ 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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{
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- if (gcry_md_open (&dfx.mdc_hash, ed->mdc_method, 0 ))
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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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+ 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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+ 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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@@ -104,7 +129,7 @@
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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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+ 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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@@ -123,7 +148,7 @@
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goto leave;
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}
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- gcry_cipher_setiv (dfx.cipher_hd, NULL, 0);
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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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@@ -144,8 +169,8 @@
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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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+ 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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@@ -155,17 +180,18 @@
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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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-
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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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+
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+ dfx->refcount++;
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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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+ 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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+ 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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+ 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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@@ -184,26 +210,28 @@
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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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+ assert (dfx->cipher_hd);
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+ assert (dfx->mdc_hash);
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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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+ 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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+ || memcmp (gcry_md_read (dfx->mdc_hash, 0),
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+ 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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+ /* 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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+ release_dfx_context (dfx);
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return rc;
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}
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@@ -214,7 +242,7 @@
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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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+ 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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@@ -226,11 +254,11 @@
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}
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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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+ 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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+ 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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@@ -279,8 +307,10 @@
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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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+ if ( dfx->cipher_hd )
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+ gcry_cipher_decrypt (dfx->cipher_hd, buf, n, NULL, 0);
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+ if ( dfx->mdc_hash )
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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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{
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@@ -289,6 +319,10 @@
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}
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*ret_len = n;
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}
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+ else if ( control == IOBUFCTRL_FREE )
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+ {
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+ release_dfx_context (dfx);
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+ }
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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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@@ -300,7 +334,7 @@
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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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+ 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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@@ -311,11 +345,18 @@
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if ( n == -1 )
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n = 0;
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if ( n )
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- gcry_cipher_decrypt (fc->cipher_hd, buf, n, NULL, 0);
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+ {
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+ if (fc->cipher_hd)
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+ gcry_cipher_decrypt (fc->cipher_hd, buf, n, NULL, 0);
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+ }
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else
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rc = -1; /* EOF */
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*ret_len = n;
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}
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+ else if ( control == IOBUFCTRL_FREE )
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+ {
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+ release_dfx_context (fc);
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+ }
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else if ( control == IOBUFCTRL_DESC )
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{
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*(char**)buf = "decode_filter";
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