[PATCH v2 7/7] bcrypt: Fix padding in format_gnutls_signature().
Hans Leidekker
hans at codeweavers.com
Mon Jan 18 05:38:29 CST 2021
From: Paul Gofman <pgofman at codeweavers.com>
Signed-off-by: Paul Gofman <pgofman at codeweavers.com>
Signed-off-by: Hans Leidekker <hans at codeweavers.com>
---
dlls/bcrypt/gnutls.c | 27 ++++-----------------------
1 file changed, 4 insertions(+), 23 deletions(-)
diff --git a/dlls/bcrypt/gnutls.c b/dlls/bcrypt/gnutls.c
index 2981dc6bc9c..efab65b8315 100644
--- a/dlls/bcrypt/gnutls.c
+++ b/dlls/bcrypt/gnutls.c
@@ -1641,9 +1641,8 @@ static NTSTATUS format_gnutls_signature( enum alg_id type, gnutls_datum_t signat
case ALG_ID_DSA:
{
int err;
- unsigned int pad_size_r, pad_size_s, sig_len = get_signature_length( type );
+ unsigned int sig_len = get_signature_length( type );
gnutls_datum_t r, s; /* format as r||s */
- unsigned char *r_data, *s_data;
if ((err = pgnutls_decode_rs_value( &signature, &r, &s )))
{
@@ -1654,21 +1653,7 @@ static NTSTATUS format_gnutls_signature( enum alg_id type, gnutls_datum_t signat
*ret_len = sig_len;
if (output_len < sig_len) return STATUS_BUFFER_TOO_SMALL;
- if (r.size % 2) /* remove prepended zero byte */
- {
- r.size--;
- r_data = r.data + 1;
- }
- else r_data = r.data;
-
- if (s.size % 2)
- {
- s.size--;
- s_data = s.data + 1;
- }
- else s_data = s.data;
-
- if (r.size + s.size > sig_len)
+ if (r.size > sig_len / 2 + 1 || s.size > sig_len / 2 + 1)
{
ERR( "we didn't get a correct signature\n" );
return STATUS_INTERNAL_ERROR;
@@ -1676,12 +1661,8 @@ static NTSTATUS format_gnutls_signature( enum alg_id type, gnutls_datum_t signat
if (output)
{
- pad_size_r = (sig_len / 2) - r.size;
- pad_size_s = (sig_len / 2) - s.size;
- memset( output, 0, sig_len );
-
- memcpy( output + pad_size_r, r_data, r.size );
- memcpy( output + (sig_len / 2) + pad_size_s, s_data, s.size );
+ export_gnutls_datum( output, sig_len / 2, &r, NULL );
+ export_gnutls_datum( output + sig_len / 2, sig_len / 2, &s, NULL );
}
free( r.data ); free( s.data );
--
2.29.2
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