From: Volker Lendecke <vl@samba.org>
Date: Fri, 20 May 2022 08:55:23 +0000 (+0200)
Subject: CVE-2022-2127: winbindd: Fix WINBINDD_PAM_AUTH_CRAP length checks
X-Git-Tag: samba-4.16.11~23
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5c6fe5a491b16bb658c191cfafb5edc0beb5fab2;p=thirdparty%2Fsamba.git

CVE-2022-2127: winbindd: Fix WINBINDD_PAM_AUTH_CRAP length checks

With WBFLAG_BIG_NTLMV2_BLOB being set plus lm_resp_len too large you
can crash winbind. We don't independently check lm_resp_len
sufficiently.

Discovered via Coverity ID 1504444 Out-of-bounds access

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15072

Signed-off-by: Volker Lendecke <vl@samba.org>
---

diff --git a/source3/winbindd/winbindd_pam_auth_crap.c b/source3/winbindd/winbindd_pam_auth_crap.c
index fdb8120a6fe..651d54b01d3 100644
--- a/source3/winbindd/winbindd_pam_auth_crap.c
+++ b/source3/winbindd/winbindd_pam_auth_crap.c
@@ -42,6 +42,9 @@ struct tevent_req *winbindd_pam_auth_crap_send(
 	struct winbindd_pam_auth_crap_state *state;
 	struct winbindd_domain *domain;
 	const char *auth_domain = NULL;
+	bool lmlength_ok = false;
+	bool ntlength_ok = false;
+	bool pwlength_ok = false;
 
 	req = tevent_req_create(mem_ctx, &state,
 				struct winbindd_pam_auth_crap_state);
@@ -140,16 +143,24 @@ struct tevent_req *winbindd_pam_auth_crap_send(
 		fstrcpy(request->data.auth_crap.workstation, lp_netbios_name());
 	}
 
-	if (request->data.auth_crap.lm_resp_len > sizeof(request->data.auth_crap.lm_resp)
-		|| request->data.auth_crap.nt_resp_len > sizeof(request->data.auth_crap.nt_resp)) {
-		if (!(request->flags & WBFLAG_BIG_NTLMV2_BLOB) ||
-		     request->extra_len != request->data.auth_crap.nt_resp_len) {
-			DBG_ERR("Invalid password length %u/%u\n",
-				request->data.auth_crap.lm_resp_len,
-				request->data.auth_crap.nt_resp_len);
-			tevent_req_nterror(req, NT_STATUS_INVALID_PARAMETER);
-			return tevent_req_post(req, ev);
-		}
+	lmlength_ok = (request->data.auth_crap.lm_resp_len <=
+		       sizeof(request->data.auth_crap.lm_resp));
+
+	ntlength_ok = (request->data.auth_crap.nt_resp_len <=
+		       sizeof(request->data.auth_crap.nt_resp));
+
+	ntlength_ok |=
+		((request->flags & WBFLAG_BIG_NTLMV2_BLOB) &&
+		 (request->extra_len == request->data.auth_crap.nt_resp_len));
+
+	pwlength_ok = lmlength_ok && ntlength_ok;
+
+	if (!pwlength_ok) {
+		DBG_ERR("Invalid password length %u/%u\n",
+			request->data.auth_crap.lm_resp_len,
+			request->data.auth_crap.nt_resp_len);
+		tevent_req_nterror(req, NT_STATUS_INVALID_PARAMETER);
+		return tevent_req_post(req, ev);
 	}
 
 	subreq = wb_domain_request_send(state, global_event_context(), domain,