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|
This is a patch against GnuPG 2.0.1. Change the directory to g10/ and
apply this patch.
2006-12-02 Werner Koch <wk@g10code.com>
* encr-data.c: Allocate DFX context on the heap and not on the
stack. Changes at several places. Fixes CVE-2006-6235.
Index: encr-data.c
===================================================================
--- encr-data.c (revision 4352)
+++ encr-data.c (working copy)
@@ -39,16 +39,37 @@
static int decode_filter ( void *opaque, int control, IOBUF a,
byte *buf, size_t *ret_len);
-typedef struct
+typedef struct decode_filter_context_s
{
gcry_cipher_hd_t cipher_hd;
gcry_md_hd_t mdc_hash;
char defer[22];
int defer_filled;
int eof_seen;
-} decode_filter_ctx_t;
+ int refcount;
+} *decode_filter_ctx_t;
+/* Helper to release the decode context. */
+static void
+release_dfx_context (decode_filter_ctx_t dfx)
+{
+ if (!dfx)
+ return;
+
+ assert (dfx->refcount);
+ if ( !--dfx->refcount )
+ {
+ gcry_cipher_close (dfx->cipher_hd);
+ dfx->cipher_hd = NULL;
+ gcry_md_close (dfx->mdc_hash);
+ dfx->mdc_hash = NULL;
+ xfree (dfx);
+ }
+}
+
+
+
/****************
* Decrypt the data, specified by ED with the key DEK.
*/
@@ -62,7 +83,11 @@
unsigned blocksize;
unsigned nprefix;
- memset( &dfx, 0, sizeof dfx );
+ dfx = xtrycalloc (1, sizeof *dfx);
+ if (!dfx)
+ return gpg_error_from_syserror ();
+ dfx->refcount = 1;
+
if ( opt.verbose && !dek->algo_info_printed )
{
const char *s = gcry_cipher_algo_name (dek->algo);
@@ -77,20 +102,20 @@
goto leave;
blocksize = gcry_cipher_get_algo_blklen (dek->algo);
if ( !blocksize || blocksize > 16 )
- log_fatal("unsupported blocksize %u\n", blocksize );
+ log_fatal ("unsupported blocksize %u\n", blocksize );
nprefix = blocksize;
if ( ed->len && ed->len < (nprefix+2) )
BUG();
if ( ed->mdc_method )
{
- if (gcry_md_open (&dfx.mdc_hash, ed->mdc_method, 0 ))
+ if (gcry_md_open (&dfx->mdc_hash, ed->mdc_method, 0 ))
BUG ();
if ( DBG_HASHING )
- gcry_md_start_debug (dfx.mdc_hash, "checkmdc");
+ gcry_md_start_debug (dfx->mdc_hash, "checkmdc");
}
- rc = gcry_cipher_open (&dfx.cipher_hd, dek->algo,
+ rc = gcry_cipher_open (&dfx->cipher_hd, dek->algo,
GCRY_CIPHER_MODE_CFB,
(GCRY_CIPHER_SECURE
| ((ed->mdc_method || dek->algo >= 100)?
@@ -104,7 +129,7 @@
/* log_hexdump( "thekey", dek->key, dek->keylen );*/
- rc = gcry_cipher_setkey (dfx.cipher_hd, dek->key, dek->keylen);
+ rc = gcry_cipher_setkey (dfx->cipher_hd, dek->key, dek->keylen);
if ( gpg_err_code (rc) == GPG_ERR_WEAK_KEY )
{
log_info(_("WARNING: message was encrypted with"
@@ -123,7 +148,7 @@
goto leave;
}
- gcry_cipher_setiv (dfx.cipher_hd, NULL, 0);
+ gcry_cipher_setiv (dfx->cipher_hd, NULL, 0);
if ( ed->len )
{
@@ -144,8 +169,8 @@
temp[i] = c;
}
- gcry_cipher_decrypt (dfx.cipher_hd, temp, nprefix+2, NULL, 0);
- gcry_cipher_sync (dfx.cipher_hd);
+ gcry_cipher_decrypt (dfx->cipher_hd, temp, nprefix+2, NULL, 0);
+ gcry_cipher_sync (dfx->cipher_hd);
p = temp;
/* log_hexdump( "prefix", temp, nprefix+2 ); */
if (dek->symmetric
@@ -155,17 +180,18 @@
goto leave;
}
- if ( dfx.mdc_hash )
- gcry_md_write (dfx.mdc_hash, temp, nprefix+2);
-
+ if ( dfx->mdc_hash )
+ gcry_md_write (dfx->mdc_hash, temp, nprefix+2);
+
+ dfx->refcount++;
if ( ed->mdc_method )
- iobuf_push_filter( ed->buf, mdc_decode_filter, &dfx );
+ iobuf_push_filter ( ed->buf, mdc_decode_filter, dfx );
else
- iobuf_push_filter( ed->buf, decode_filter, &dfx );
+ iobuf_push_filter ( ed->buf, decode_filter, dfx );
proc_packets ( procctx, ed->buf );
ed->buf = NULL;
- if ( ed->mdc_method && dfx.eof_seen == 2 )
+ if ( ed->mdc_method && dfx->eof_seen == 2 )
rc = gpg_error (GPG_ERR_INV_PACKET);
else if ( ed->mdc_method )
{
@@ -184,26 +210,28 @@
bytes are appended. */
int datalen = gcry_md_get_algo_dlen (ed->mdc_method);
- gcry_cipher_decrypt (dfx.cipher_hd, dfx.defer, 22, NULL, 0);
- gcry_md_write (dfx.mdc_hash, dfx.defer, 2);
- gcry_md_final (dfx.mdc_hash);
+ assert (dfx->cipher_hd);
+ assert (dfx->mdc_hash);
+ gcry_cipher_decrypt (dfx->cipher_hd, dfx->defer, 22, NULL, 0);
+ gcry_md_write (dfx->mdc_hash, dfx->defer, 2);
+ gcry_md_final (dfx->mdc_hash);
- if (dfx.defer[0] != '\xd3' || dfx.defer[1] != '\x14' )
+ if (dfx->defer[0] != '\xd3' || dfx->defer[1] != '\x14' )
{
log_error("mdc_packet with invalid encoding\n");
rc = gpg_error (GPG_ERR_INV_PACKET);
}
else if (datalen != 20
- || memcmp (gcry_md_read (dfx.mdc_hash, 0),dfx.defer+2,datalen))
+ || memcmp (gcry_md_read (dfx->mdc_hash, 0),
+ dfx->defer+2,datalen ))
rc = gpg_error (GPG_ERR_BAD_SIGNATURE);
- /* log_printhex("MDC message:", dfx.defer, 22); */
- /* log_printhex("MDC calc:", gcry_md_read (dfx.mdc_hash,0), datalen); */
+ /* log_printhex("MDC message:", dfx->defer, 22); */
+ /* log_printhex("MDC calc:", gcry_md_read (dfx->mdc_hash,0), datalen); */
}
leave:
- gcry_cipher_close (dfx.cipher_hd);
- gcry_md_close (dfx.mdc_hash);
+ release_dfx_context (dfx);
return rc;
}
@@ -214,7 +242,7 @@
mdc_decode_filter (void *opaque, int control, IOBUF a,
byte *buf, size_t *ret_len)
{
- decode_filter_ctx_t *dfx = opaque;
+ decode_filter_ctx_t dfx = opaque;
size_t n, size = *ret_len;
int rc = 0;
int c;
@@ -226,11 +254,11 @@
}
else if( control == IOBUFCTRL_UNDERFLOW )
{
- assert(a);
- assert( size > 44 );
+ assert (a);
+ assert ( size > 44 );
/* Get at least 22 bytes and put it somewhere ahead in the buffer. */
- for(n=22; n < 44 ; n++ )
+ for (n=22; n < 44 ; n++ )
{
if( (c = iobuf_get(a)) == -1 )
break;
@@ -279,8 +307,10 @@
if ( n )
{
- gcry_cipher_decrypt (dfx->cipher_hd, buf, n, NULL, 0);
- gcry_md_write (dfx->mdc_hash, buf, n);
+ if ( dfx->cipher_hd )
+ gcry_cipher_decrypt (dfx->cipher_hd, buf, n, NULL, 0);
+ if ( dfx->mdc_hash )
+ gcry_md_write (dfx->mdc_hash, buf, n);
}
else
{
@@ -289,6 +319,10 @@
}
*ret_len = n;
}
+ else if ( control == IOBUFCTRL_FREE )
+ {
+ release_dfx_context (dfx);
+ }
else if ( control == IOBUFCTRL_DESC )
{
*(char**)buf = "mdc_decode_filter";
@@ -300,7 +334,7 @@
static int
decode_filter( void *opaque, int control, IOBUF a, byte *buf, size_t *ret_len)
{
- decode_filter_ctx_t *fc = opaque;
+ decode_filter_ctx_t fc = opaque;
size_t n, size = *ret_len;
int rc = 0;
@@ -311,11 +345,18 @@
if ( n == -1 )
n = 0;
if ( n )
- gcry_cipher_decrypt (fc->cipher_hd, buf, n, NULL, 0);
+ {
+ if (fc->cipher_hd)
+ gcry_cipher_decrypt (fc->cipher_hd, buf, n, NULL, 0);
+ }
else
rc = -1; /* EOF */
*ret_len = n;
}
+ else if ( control == IOBUFCTRL_FREE )
+ {
+ release_dfx_context (fc);
+ }
else if ( control == IOBUFCTRL_DESC )
{
*(char**)buf = "decode_filter";
|
