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From 202d69267c8550b850438877fb51c3d2c992949d Mon Sep 17 00:00:00 2001
From: Stefan Metzmacher <metze@samba.org>
Date: Tue, 1 Dec 2015 08:46:45 +0100
Subject: [PATCH 01/10] CVE-2016-2110: s3:ntlmssp: set and use
ntlmssp_state->allow_lm_key
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
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>
---
source3/libsmb/ntlmssp.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/source3/libsmb/ntlmssp.c
+++ b/source3/libsmb/ntlmssp.c
@@ -176,17 +176,19 @@ void ntlmssp_want_feature_list(struct nt
* also add NTLMSSP_NEGOTIATE_SEAL here. JRA.
*/
if (in_list("NTLMSSP_FEATURE_SESSION_KEY", feature_list, True)) {
- ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SIGN;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_SIGN;
}
if (in_list("NTLMSSP_FEATURE_SIGN", feature_list, True)) {
- ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SIGN;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_SIGN;
}
if(in_list("NTLMSSP_FEATURE_SEAL", feature_list, True)) {
- ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_SEAL;
}
if (in_list("NTLMSSP_FEATURE_CCACHE", feature_list, true)) {
ntlmssp_state->use_ccache = true;
}
+
+ ntlmssp_state->neg_flags |= ntlmssp_state->required_flags;
}
/**
@@ -199,17 +201,20 @@ void ntlmssp_want_feature(struct ntlmssp
{
/* As per JRA's comment above */
if (feature & NTLMSSP_FEATURE_SESSION_KEY) {
- ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SIGN;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_SIGN;
}
if (feature & NTLMSSP_FEATURE_SIGN) {
- ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SIGN;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_SIGN;
}
if (feature & NTLMSSP_FEATURE_SEAL) {
- ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_SIGN;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_SEAL;
}
if (feature & NTLMSSP_FEATURE_CCACHE) {
ntlmssp_state->use_ccache = true;
}
+
+ ntlmssp_state->neg_flags |= ntlmssp_state->required_flags;
}
/**
@@ -387,7 +392,12 @@ static NTSTATUS ntlmssp_client_initial(s
}
if (ntlmssp_state->use_ntlmv2) {
- ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_NTLM2;
+ ntlmssp_state->required_flags |= NTLMSSP_NEGOTIATE_NTLM2;
+ ntlmssp_state->allow_lm_key = false;
+ }
+
+ if (ntlmssp_state->allow_lm_key) {
+ ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_LM_KEY;
}
/* generate the ntlmssp negotiate packet */
@@ -422,6 +432,86 @@ static NTSTATUS ntlmssp_client_initial(s
return NT_STATUS_MORE_PROCESSING_REQUIRED;
}
+static NTSTATUS ntlmssp3_handle_neg_flags(struct ntlmssp_state *ntlmssp_state,
+ uint32_t flags)
+{
+ uint32_t missing_flags = ntlmssp_state->required_flags;
+
+ if (flags & NTLMSSP_NEGOTIATE_UNICODE) {
+ ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_UNICODE;
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_OEM;
+ ntlmssp_state->unicode = true;
+ } else {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_UNICODE;
+ ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_OEM;
+ ntlmssp_state->unicode = false;
+ }
+
+ /*
+ * NTLMSSP_NEGOTIATE_NTLM2 (NTLMSSP_NEGOTIATE_EXTENDED_SESSIONSECURITY)
+ * has priority over NTLMSSP_NEGOTIATE_LM_KEY
+ */
+ if (!(flags & NTLMSSP_NEGOTIATE_NTLM2)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_NTLM2;
+ }
+
+ if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
+ }
+
+ if (!(flags & NTLMSSP_NEGOTIATE_LM_KEY)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_LM_KEY;
+ }
+
+ if (!(flags & NTLMSSP_NEGOTIATE_ALWAYS_SIGN)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_ALWAYS_SIGN;
+ }
+
+ if (!(flags & NTLMSSP_NEGOTIATE_128)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_128;
+ }
+
+ if (!(flags & NTLMSSP_NEGOTIATE_56)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_56;
+ }
+
+ if (!(flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_KEY_EXCH;
+ }
+
+ if (!(flags & NTLMSSP_NEGOTIATE_SIGN)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_SIGN;
+ }
+
+ if (!(flags & NTLMSSP_NEGOTIATE_SEAL)) {
+ ntlmssp_state->neg_flags &= ~NTLMSSP_NEGOTIATE_SEAL;
+ }
+
+ if ((flags & NTLMSSP_REQUEST_TARGET)) {
+ ntlmssp_state->neg_flags |= NTLMSSP_REQUEST_TARGET;
+ }
+
+ missing_flags &= ~ntlmssp_state->neg_flags;
+ if (missing_flags != 0) {
+ NTSTATUS status = NT_STATUS_RPC_SEC_PKG_ERROR;
+ DEBUG(1, ("%s: Got challenge flags[0x%08x] "
+ "- possible downgrade detected! "
+ "missing_flags[0x%08x] - %s\n",
+ __func__,
+ (unsigned)flags,
+ (unsigned)missing_flags,
+ nt_errstr(status)));
+ debug_ntlmssp_flags(missing_flags);
+ DEBUGADD(4, ("neg_flags[0x%08x]\n",
+ (unsigned)ntlmssp_state->neg_flags));
+ debug_ntlmssp_flags(ntlmssp_state->neg_flags);
+
+ return status;
+ }
+
+ return NT_STATUS_OK;
+}
+
/**
* Next state function for the Challenge Packet. Generate an auth packet.
*
@@ -448,6 +538,26 @@ static NTSTATUS ntlmssp_client_challenge
DATA_BLOB encrypted_session_key = data_blob_null;
NTSTATUS nt_status = NT_STATUS_OK;
+ if (!msrpc_parse(ntlmssp_state, &reply, "CdBd",
+ "NTLMSSP",
+ &ntlmssp_command,
+ &server_domain_blob,
+ &chal_flags)) {
+ DEBUG(1, ("Failed to parse the NTLMSSP Challenge: (#1)\n"));
+ dump_data(2, reply.data, reply.length);
+
+ return NT_STATUS_INVALID_PARAMETER;
+ }
+ data_blob_free(&server_domain_blob);
+
+ DEBUG(3, ("Got challenge flags:\n"));
+ debug_ntlmssp_flags(chal_flags);
+
+ nt_status = ntlmssp3_handle_neg_flags(ntlmssp_state, chal_flags);
+ if (!NT_STATUS_IS_OK(nt_status)) {
+ return nt_status;
+ }
+
if (ntlmssp_state->use_ccache) {
struct wbcCredentialCacheParams params;
struct wbcCredentialCacheInfo *info = NULL;
@@ -498,17 +608,6 @@ static NTSTATUS ntlmssp_client_challenge
noccache:
- if (!msrpc_parse(ntlmssp_state, &reply, "CdBd",
- "NTLMSSP",
- &ntlmssp_command,
- &server_domain_blob,
- &chal_flags)) {
- DEBUG(1, ("Failed to parse the NTLMSSP Challenge: (#1)\n"));
- dump_data(2, reply.data, reply.length);
-
- return NT_STATUS_INVALID_PARAMETER;
- }
-
if (DEBUGLEVEL >= 10) {
struct CHALLENGE_MESSAGE *challenge = talloc(
talloc_tos(), struct CHALLENGE_MESSAGE);
@@ -525,13 +624,6 @@ noccache:
}
}
- data_blob_free(&server_domain_blob);
-
- DEBUG(3, ("Got challenge flags:\n"));
- debug_ntlmssp_flags(chal_flags);
-
- ntlmssp_handle_neg_flags(ntlmssp_state, chal_flags, lp_client_lanman_auth());
-
if (ntlmssp_state->unicode) {
if (chal_flags & NTLMSSP_NEGOTIATE_TARGET_INFO) {
chal_parse_string = "CdUdbddB";
@@ -769,6 +861,7 @@ NTSTATUS ntlmssp_client_start(TALLOC_CTX
ntlmssp_state->unicode = True;
ntlmssp_state->use_ntlmv2 = use_ntlmv2;
+ ntlmssp_state->allow_lm_key = lp_client_lanman_auth();
ntlmssp_state->expected_state = NTLMSSP_INITIAL;
@@ -780,6 +873,10 @@ NTSTATUS ntlmssp_client_start(TALLOC_CTX
NTLMSSP_NEGOTIATE_KEY_EXCH |
NTLMSSP_REQUEST_TARGET;
+ if (ntlmssp_state->use_ntlmv2) {
+ ntlmssp_state->allow_lm_key = false;
+ }
+
ntlmssp_state->client.netbios_name = talloc_strdup(ntlmssp_state, netbios_name);
if (!ntlmssp_state->client.netbios_name) {
talloc_free(ntlmssp_state);
--- a/libcli/auth/ntlmssp.h
+++ b/libcli/auth/ntlmssp.h
@@ -83,6 +83,7 @@ struct ntlmssp_state
DATA_BLOB nt_resp;
DATA_BLOB session_key;
+ uint32_t required_flags;
uint32_t neg_flags; /* the current state of negotiation with the NTLMSSP partner */
/**
|
