s3-spnego: Fix Bug #6815. Windows 2008 R2 SPNEGO negTokenTarg parsing failure.

When parsing a SPNEGO session setup retry (falling back from KRB5 to NTLMSSP),
we failed to parse the ASN1_ENUMERATED negResult in the negTokenTarg, thus
failing spnego_parse_auth() completely.

By just using the shared spnego/asn1 code, we get the parsing the correct way.

Guenther

2 files changed, 15 insertions, 20 deletions

diff --git a/source3/Makefile.in b/source3/Makefile.in
index 90faadf001..d12c9911c3 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -506,7 +506,9 @@ SCHANNEL_OBJ = ../libcli/auth/credentials.o \
 	       passdb/secrets_schannel.o
 
 LIBSMB_OBJ = libsmb/clientgen.o libsmb/cliconnect.o libsmb/clifile.o \
-	     libsmb/clikrb5.o libsmb/clispnego.o ../lib/util/asn1.o \
+	     libsmb/clikrb5.o libsmb/clispnego.o \
+	     ../libcli/auth/spnego_parse.o \
+	     ../lib/util/asn1.o \
 	     libsmb/clirap.o libsmb/clierror.o libsmb/climessage.o \
 	     libsmb/clireadwrite.o libsmb/clilist.o libsmb/cliprint.o \
 	     libsmb/clitrans.o libsmb/clisecdesc.o libsmb/clidgram.o \
diff --git a/source3/libsmb/clispnego.c b/source3/libsmb/clispnego.c
index 5d7e43d941..1103ef84b6 100644
--- a/source3/libsmb/clispnego.c
+++ b/source3/libsmb/clispnego.c
@@ -495,31 +495,24 @@ DATA_BLOB spnego_gen_auth(DATA_BLOB blob)
 */
 bool spnego_parse_auth(DATA_BLOB blob, DATA_BLOB *auth)
 {
-	ASN1_DATA *data;
+	ssize_t len;
+	struct spnego_data token;
 
-	data = asn1_init(talloc_tos());
-	if (data == NULL) {
+	len = spnego_read_data(talloc_tos(), blob, &token);
+	if (len == -1) {
+		DEBUG(3,("spnego_parse_auth: spnego_read_data failed\n"));
 		return false;
 	}
 
-	asn1_load(data, blob);
-	asn1_start_tag(data, ASN1_CONTEXT(1));
-	asn1_start_tag(data, ASN1_SEQUENCE(0));
-	asn1_start_tag(data, ASN1_CONTEXT(2));
-	asn1_read_OctetString(data, talloc_autofree_context(), auth);
-	asn1_end_tag(data);
-	asn1_end_tag(data);
-	asn1_end_tag(data);
-
-	if (data->has_error) {
-		DEBUG(3,("spnego_parse_auth failed at %d\n", (int)data->ofs));
-		data_blob_free(auth);
-		asn1_free(data);
-		return False;
+	if (token.type != SPNEGO_NEG_TOKEN_TARG) {
+		DEBUG(3,("spnego_parse_auth: wrong token type: %d\n",
+			token.type));
+		return false;
 	}
 
-	asn1_free(data);
-	return True;
+	*auth = token.negTokenTarg.responseToken;
+
+	return true;
 }
 
 /*