CVE-2016-2110: auth/gensec: add gensec_may_reset_crypto() infrastructure

[MS-SPNG] requires the NTLMSSP RC4 states to be reset after
the SPNEGO exchange with mechListMic verification (new_spnego).

This provides the infrastructure for this feature.

The 'reset_full' parameter is needed to support the broken
behavior that windows only resets the RC4 states but not the
sequence numbers. Which means this functionality is completely
useless... But we want to work against all windows versions...

BUG: https://bugzilla.samba.org/show_bug.cgi?id=11644

Signed-off-by: Stefan Metzmacher <metze@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>

diff --git a/auth/gensec/gensec.c b/auth/gensec/gensec.c
index 548091a54ea1f7ea7873ac4340a38e82e44b6170..4d0968b298f74706620a93ab8471a4ff7883ede2 100644 (file)
--- a/auth/gensec/gensec.c
+++ b/auth/gensec/gensec.c
@@ -30,6 +30,16 @@
 #include "auth/gensec/gensec_internal.h"
 #include "librpc/gen_ndr/dcerpc.h"
 
+_PRIVATE_ NTSTATUS gensec_may_reset_crypto(struct gensec_security *gensec_security,
+                                          bool full_reset)
+{
+       if (!gensec_security->ops->may_reset_crypto) {
+               return NT_STATUS_OK;
+       }
+
+       return gensec_security->ops->may_reset_crypto(gensec_security, full_reset);
+}
+
 /*
   wrappers for the gensec function pointers
 */

diff --git a/auth/gensec/gensec_internal.h b/auth/gensec/gensec_internal.h
index 27511966ca9ad17fd64d49454a78b178b0400886..55352417e99a5e7b29f6603e0916b09a1914ff66 100644 (file)
--- a/auth/gensec/gensec_internal.h
+++ b/auth/gensec/gensec_internal.h
@@ -47,6 +47,8 @@ struct gensec_security_ops {
        NTSTATUS (*update_recv)(struct tevent_req *req,
                                TALLOC_CTX *out_mem_ctx,
                                DATA_BLOB *out);
+       NTSTATUS (*may_reset_crypto)(struct gensec_security *gensec_security,
+                                    bool full_reset);
        NTSTATUS (*seal_packet)(struct gensec_security *gensec_security, TALLOC_CTX *sig_mem_ctx,
                                uint8_t *data, size_t length,
                                const uint8_t *whole_pdu, size_t pdu_length,
@@ -121,4 +123,7 @@ struct gensec_critical_sizes {
        int sizeof_gensec_security;
 };
 
+NTSTATUS gensec_may_reset_crypto(struct gensec_security *gensec_security,
+                                bool full_reset);
+
 #endif /* __GENSEC_H__ */

diff --git a/auth/gensec/spnego.c b/auth/gensec/spnego.c
index 7978f7bcab4d6db5a80c5463f962dc300c3eaa49..1d4b172e476ed628df3f18ff89df71f42d439f7d 100644 (file)
--- a/auth/gensec/spnego.c
+++ b/auth/gensec/spnego.c
@@ -1426,7 +1426,14 @@ static NTSTATUS gensec_spnego_update_wrapper(struct gensec_security *gensec_secu
        data_blob_free(&spnego_state->in_frag);
        spnego_state->in_needed = 0;
        if (NT_STATUS_IS_OK(status)) {
+               bool reset_full = true;
+
                gensec_security->child_security = spnego_state->sub_sec_security;
+
+               reset_full = !spnego_state->done_mic_check;
+
+               status = gensec_may_reset_crypto(spnego_state->sub_sec_security,
+                                                reset_full);
        }
        if (!NT_STATUS_IS_OK(status) &&
            !NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {