auth: Use constant-time memcmp when comparing sensitive buffers

This helps to avoid timing attacks.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15010

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

24 files changed, 99 insertions, 69 deletions

diff --git a/auth/gensec/schannel.c b/auth/gensec/schannel.c
index 6ebbe8f3179..2fbfb019124 100644
--- a/auth/gensec/schannel.c
+++ b/auth/gensec/schannel.c
@@ -649,7 +649,7 @@ static NTSTATUS netsec_incoming_packet(struct schannel_state *state,
 		return NT_STATUS_ACCESS_DENIED;
 	}
 
-	ret = memcmp(checksum, sig->data+16, checksum_length);
+	ret = memcmp_const_time(checksum, sig->data+16, checksum_length);
 	if (ret != 0) {
 		dump_data_pw("calc digest:", checksum, checksum_length);
 		dump_data_pw("wire digest:", sig->data+16, checksum_length);
@@ -665,7 +665,7 @@ static NTSTATUS netsec_incoming_packet(struct schannel_state *state,
 
 	ZERO_ARRAY(checksum);
 
-	ret = memcmp(seq_num, sig->data+8, 8);
+	ret = memcmp_const_time(seq_num, sig->data+8, 8);
 	if (ret != 0) {
 		dump_data_pw("calc seq num:", seq_num, 8);
 		dump_data_pw("wire seq num:", sig->data+8, 8);
diff --git a/auth/ntlmssp/ntlmssp_ndr.c b/auth/ntlmssp/ntlmssp_ndr.c
index c8b16ccd413..6de00427bbd 100644
--- a/auth/ntlmssp/ntlmssp_ndr.c
+++ b/auth/ntlmssp/ntlmssp_ndr.c
@@ -31,7 +31,7 @@ do { \
 	if (!NDR_ERR_CODE_IS_SUCCESS(__ndr_err)) { \
 		return ndr_map_error2ntstatus(__ndr_err); \
 	} \
-	if (memcmp(r->Signature, "NTLMSSP\0", 8)) {\
+	if (memcmp_const_time(r->Signature, "NTLMSSP\0", 8)) { \
 		return NT_STATUS_INVALID_PARAMETER; \
 	} \
 	return NT_STATUS_OK; \
diff --git a/auth/ntlmssp/ntlmssp_server.c b/auth/ntlmssp/ntlmssp_server.c
index e077c2f7379..55688602881 100644
--- a/auth/ntlmssp/ntlmssp_server.c
+++ b/auth/ntlmssp/ntlmssp_server.c
@@ -1095,8 +1095,8 @@ static NTSTATUS ntlmssp_server_postauth(struct gensec_security *gensec_security,
 		}
 		gnutls_hmac_deinit(hmac_hnd, mic_buffer);
 
-		cmp = memcmp(request.data + NTLMSSP_MIC_OFFSET,
-			     mic_buffer, NTLMSSP_MIC_SIZE);
+		cmp = memcmp_const_time(request.data + NTLMSSP_MIC_OFFSET,
+					mic_buffer, NTLMSSP_MIC_SIZE);
 		if (cmp != 0) {
 			DEBUG(1,("%s: invalid NTLMSSP_MIC for "
 				 "user=[%s] domain=[%s] workstation=[%s]\n",
diff --git a/auth/ntlmssp/ntlmssp_sign.c b/auth/ntlmssp/ntlmssp_sign.c
index 89f1aa04f7a..b831308aa2c 100644
--- a/auth/ntlmssp/ntlmssp_sign.c
+++ b/auth/ntlmssp/ntlmssp_sign.c
@@ -291,7 +291,7 @@ NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state,
 
 	if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 		if (local_sig.length != sig->length ||
-		    memcmp(local_sig.data, sig->data, sig->length) != 0) {
+		    memcmp_const_time(local_sig.data, sig->data, sig->length) != 0) {
 			DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
 			dump_data(5, local_sig.data, local_sig.length);
 
@@ -304,7 +304,7 @@ NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state,
 		}
 	} else {
 		if (local_sig.length != sig->length ||
-		    memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
+		    memcmp_const_time(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
 			DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
 			dump_data(5, local_sig.data, local_sig.length);
 
diff --git a/lib/util/data_blob.c b/lib/util/data_blob.c
index da1730dccf5..1b05809119d 100644
--- a/lib/util/data_blob.c
+++ b/lib/util/data_blob.c
@@ -21,6 +21,7 @@
 #include "replace.h"
 #include "attr.h"
 #include "data_blob.h"
+#include "lib/util/samba_util.h"
 
 const DATA_BLOB data_blob_null = { NULL, 0 };
 
@@ -130,6 +131,29 @@ _PUBLIC_ int data_blob_cmp(const DATA_BLOB *d1, const DATA_BLOB *d2)
 }
 
 /**
+check if two data blobs are equal, where the time taken should not depend on the
+contents of either blob.
+**/
+_PUBLIC_ int data_blob_cmp_const_time(const DATA_BLOB *d1, const DATA_BLOB *d2)
+{
+	int ret;
+	if (d1->data == NULL && d2->data != NULL) {
+		return -1;
+	}
+	if (d1->data != NULL && d2->data == NULL) {
+		return 1;
+	}
+	if (d1->data == d2->data) {
+		return d1->length - d2->length;
+	}
+	ret = memcmp_const_time(d1->data, d2->data, MIN(d1->length, d2->length));
+	if (ret == 0) {
+		return d1->length - d2->length;
+	}
+	return ret;
+}
+
+/**
 print the data_blob as hex string
 **/
 _PUBLIC_ char *data_blob_hex_string_lower(TALLOC_CTX *mem_ctx, const DATA_BLOB *blob)
diff --git a/lib/util/data_blob.h b/lib/util/data_blob.h
index 7a0dc3b0014..0f3eae16592 100644
--- a/lib/util/data_blob.h
+++ b/lib/util/data_blob.h
@@ -87,6 +87,12 @@ check if two data blobs are equal
 _PUBLIC_ int data_blob_cmp(const DATA_BLOB *d1, const DATA_BLOB *d2);
 
 /**
+check if two data blobs are equal, where the time taken should not depend on the
+contents of either blob.
+**/
+_PUBLIC_ int data_blob_cmp_const_time(const DATA_BLOB *d1, const DATA_BLOB *d2);
+
+/**
 print the data_blob as hex string
 **/
 _PUBLIC_ char *data_blob_hex_string_upper(TALLOC_CTX *mem_ctx, const DATA_BLOB *blob);
diff --git a/libcli/auth/credentials.c b/libcli/auth/credentials.c
index 23339d98bfa..bd257410c5c 100644
--- a/libcli/auth/credentials.c
+++ b/libcli/auth/credentials.c
@@ -659,7 +659,7 @@ bool netlogon_creds_client_check(struct netlogon_creds_CredentialState *creds,
 			const struct netr_Credential *received_credentials)
 {
 	if (!received_credentials ||
-	    memcmp(received_credentials->data, creds->server.data, 8) != 0) {
+	    memcmp_const_time(received_credentials->data, creds->server.data, 8) != 0) {
 		DEBUG(2,("credentials check failed\n"));
 		return false;
 	}
@@ -678,7 +678,7 @@ next comes the server specific functions
 static bool netlogon_creds_server_check_internal(const struct netlogon_creds_CredentialState *creds,
 						 const struct netr_Credential *received_credentials)
 {
-	if (memcmp(received_credentials->data, creds->client.data, 8) != 0) {
+	if (memcmp_const_time(received_credentials->data, creds->client.data, 8) != 0) {
 		DEBUG(2,("credentials check failed\n"));
 		dump_data_pw("client creds", creds->client.data, 8);
 		dump_data_pw("calc   creds", received_credentials->data, 8);
diff --git a/libcli/auth/netlogon_creds_cli.c b/libcli/auth/netlogon_creds_cli.c
index e92a042c012..369e3d94d3f 100644
--- a/libcli/auth/netlogon_creds_cli.c
+++ b/libcli/auth/netlogon_creds_cli.c
@@ -652,7 +652,7 @@ bool netlogon_creds_cli_validate(struct netlogon_creds_cli_context *context,
 		return false;
 	}
 
-	cmp = data_blob_cmp(&blob1, &blob2);
+	cmp = data_blob_cmp_const_time(&blob1, &blob2);
 
 	TALLOC_FREE(frame);
 
@@ -3227,8 +3227,8 @@ static void netlogon_creds_cli_ServerGetTrustInfo_done(struct tevent_req *subreq
 		return;
 	}
 
-	cmp = memcmp(state->new_owf_password.hash,
-		     zero.hash, sizeof(zero.hash));
+	cmp = memcmp_const_time(state->new_owf_password.hash,
+				zero.hash, sizeof(zero.hash));
 	if (cmp != 0) {
 		status = netlogon_creds_des_decrypt(&state->tmp_creds,
 						    &state->new_owf_password);
@@ -3237,8 +3237,8 @@ static void netlogon_creds_cli_ServerGetTrustInfo_done(struct tevent_req *subreq
 			return;
 		}
 	}
-	cmp = memcmp(state->old_owf_password.hash,
-		     zero.hash, sizeof(zero.hash));
+	cmp = memcmp_const_time(state->old_owf_password.hash,
+				zero.hash, sizeof(zero.hash));
 	if (cmp != 0) {
 		status = netlogon_creds_des_decrypt(&state->tmp_creds,
 						    &state->old_owf_password);
diff --git a/libcli/auth/ntlm_check.c b/libcli/auth/ntlm_check.c
index 846e0c07cd5..d71bdb3b1a4 100644
--- a/libcli/auth/ntlm_check.c
+++ b/libcli/auth/ntlm_check.c
@@ -71,7 +71,7 @@ static bool smb_pwd_check_ntlmv1(TALLOC_CTX *mem_ctx,
 	DEBUGADD(100,("Value from encryption was |\n"));
 	dump_data(100, p24, 24);
 #endif
-	ok = (memcmp(p24, nt_response->data, 24) == 0);
+	ok = (memcmp_const_time(p24, nt_response->data, 24) == 0);
 	if (!ok) {
 		return false;
 	}
@@ -157,7 +157,7 @@ static bool smb_pwd_check_ntlmv2(TALLOC_CTX *mem_ctx,
 #endif
 	data_blob_clear_free(&client_key_data);
 
-	ok = (memcmp(value_from_encryption, ntv2_response->data, 16) == 0);
+	ok = (memcmp_const_time(value_from_encryption, ntv2_response->data, 16) == 0);
 	if (!ok) {
 		return false;
 	}
@@ -271,7 +271,7 @@ NTSTATUS hash_password_check(TALLOC_CTX *mem_ctx,
 	}
 
 	if (client_nt && stored_nt) {
-		if (memcmp(client_nt->hash, stored_nt->hash, sizeof(stored_nt->hash)) == 0) {
+		if (memcmp_const_time(client_nt->hash, stored_nt->hash, sizeof(stored_nt->hash)) == 0) {
 			return NT_STATUS_OK;
 		} else {
 			DEBUG(3,("hash_password_check: Interactive logon: NT password check failed for user %s\n",
@@ -289,7 +289,7 @@ NTSTATUS hash_password_check(TALLOC_CTX *mem_ctx,
 			return NT_STATUS_NOT_FOUND;
 		}
 
-		if (memcmp(client_lanman->hash, stored_lanman->hash, sizeof(stored_lanman->hash)) == 0) {
+		if (memcmp_const_time(client_lanman->hash, stored_lanman->hash, sizeof(stored_lanman->hash)) == 0) {
 			return NT_STATUS_OK;
 		} else {
 			DEBUG(3,("hash_password_check: Interactive logon: LANMAN password check failed for user %s\n",
diff --git a/libcli/smb/smbXcli_base.c b/libcli/smb/smbXcli_base.c
index 57d39d60fca..60c3da5b691 100644
--- a/libcli/smb/smbXcli_base.c
+++ b/libcli/smb/smbXcli_base.c
@@ -3998,9 +3998,9 @@ static NTSTATUS smb2cli_conn_dispatch_incoming(struct smbXcli_conn *conn,
 			if (signing_key) {
 				int cmp;
 
-				cmp = memcmp(inhdr+SMB2_HDR_SIGNATURE,
-					     state->smb2.hdr+SMB2_HDR_SIGNATURE,
-					     16);
+				cmp = memcmp_const_time(inhdr+SMB2_HDR_SIGNATURE,
+							state->smb2.hdr+SMB2_HDR_SIGNATURE,
+							16);
 				if (cmp == 0) {
 					state->smb2.signing_skipped = true;
 					signing_key = NULL;
diff --git a/libcli/smb/smb_signing.c b/libcli/smb/smb_signing.c
index f01865c9bc5..ee9b854275a 100644
--- a/libcli/smb/smb_signing.c
+++ b/libcli/smb/smb_signing.c
@@ -339,7 +339,7 @@ bool smb1_signing_check_pdu(struct smb1_signing_state *si,
 	}
 
 	reply_sent_mac = &inhdr[HDR_SS_FIELD];
-	good = (memcmp(reply_sent_mac, calc_md5_mac, 8) == 0);
+	good = (memcmp_const_time(reply_sent_mac, calc_md5_mac, 8) == 0);
 
 	if (!good) {
 		int i;
@@ -354,7 +354,7 @@ bool smb1_signing_check_pdu(struct smb1_signing_state *si,
 		for (i = -sign_range; i < sign_range; i++) {
 			smb1_signing_md5(&si->mac_key, inhdr, len,
 					seqnum+i, calc_md5_mac);
-			if (memcmp(reply_sent_mac, calc_md5_mac, 8) == 0) {
+			if (memcmp_const_time(reply_sent_mac, calc_md5_mac, 8) == 0) {
 				DBG_ERR("out of seq. seq num %u matches. "
 					 "We were expecting seq %u\n",
 					 (unsigned int)seqnum+i,
diff --git a/source3/librpc/crypto/gse_krb5.c b/source3/librpc/crypto/gse_krb5.c
index 83741c914a3..13547047165 100644
--- a/source3/librpc/crypto/gse_krb5.c
+++ b/source3/librpc/crypto/gse_krb5.c
@@ -240,8 +240,8 @@ static krb5_error_code fill_mem_keytab_from_secrets(krb5_context krbctx,
 		 * check if keytab is up to date */
 
 		if ((ct->length == KRB5_KEY_LENGTH(KRB5_KT_KEY(&kt_entry))) &&
-		    (memcmp(KRB5_KEY_DATA(KRB5_KT_KEY(&kt_entry)),
-					ct->data, ct->length) == 0)) {
+		    (memcmp_const_time(KRB5_KEY_DATA(KRB5_KT_KEY(&kt_entry)),
+				       ct->data, ct->length) == 0)) {
 			/* keytab is already up to date, return */
 			smb_krb5_kt_free_entry(krbctx, &kt_entry);
 			goto out;
diff --git a/source3/passdb/machine_account_secrets.c b/source3/passdb/machine_account_secrets.c
index 35f72c219f4..203b5ee0eb5 100644
--- a/source3/passdb/machine_account_secrets.c
+++ b/source3/passdb/machine_account_secrets.c
@@ -1873,9 +1873,9 @@ static NTSTATUS secrets_check_password_change(const struct secrets_domain_info1
 		return NT_STATUS_NETWORK_CREDENTIAL_CONFLICT;
 	}
 
-	cmp = memcmp(sn->password->nt_hash.hash,
-		     cn->password->nt_hash.hash,
-		     16);
+	cmp = memcmp_const_time(sn->password->nt_hash.hash,
+				cn->password->nt_hash.hash,
+				16);
 	if (cmp != 0) {
 		DBG_ERR("next password.nt_hash differs for %s.\n",
 			domain);
@@ -1883,9 +1883,9 @@ static NTSTATUS secrets_check_password_change(const struct secrets_domain_info1
 		return NT_STATUS_NETWORK_CREDENTIAL_CONFLICT;
 	}
 
-	cmp = memcmp(stored->password->nt_hash.hash,
-		     cookie->password->nt_hash.hash,
-		     16);
+	cmp = memcmp_const_time(stored->password->nt_hash.hash,
+				cookie->password->nt_hash.hash,
+				16);
 	if (cmp != 0) {
 		DBG_ERR("password.nt_hash differs for %s.\n",
 			domain);
diff --git a/source3/rpc_client/cli_netlogon.c b/source3/rpc_client/cli_netlogon.c
index f446f0c8724..e76d5b8bdc5 100644
--- a/source3/rpc_client/cli_netlogon.c
+++ b/source3/rpc_client/cli_netlogon.c
@@ -325,9 +325,9 @@ again:
 	status = netlogon_creds_cli_get(creds_ctx, frame, &creds);
 
 	if (NT_STATUS_IS_OK(status)) {
-		int cmp = memcmp(found_session_key,
-				 creds->session_key,
-				 sizeof(found_session_key));
+		int cmp = memcmp_const_time(found_session_key,
+					    creds->session_key,
+					    sizeof(found_session_key));
 		found_existing_creds = (cmp != 0);
 
 		memcpy(found_session_key,
@@ -356,9 +356,9 @@ again:
 		status = netlogon_creds_cli_get(creds_ctx, frame, &creds);
 
 		if (NT_STATUS_IS_OK(status)) {
-			int cmp = memcmp(found_session_key,
-					 creds->session_key,
-					 sizeof(found_session_key));
+			int cmp = memcmp_const_time(found_session_key,
+						    creds->session_key,
+						    sizeof(found_session_key));
 			found_existing_creds = (cmp != 0);
 
 			memcpy(found_session_key, creds->session_key,
diff --git a/source3/rpc_server/netlogon/srv_netlog_nt.c b/source3/rpc_server/netlogon/srv_netlog_nt.c
index 5906464a9f3..b1f4d9c2b04 100644
--- a/source3/rpc_server/netlogon/srv_netlog_nt.c
+++ b/source3/rpc_server/netlogon/srv_netlog_nt.c
@@ -1577,7 +1577,7 @@ NTSTATUS _netr_ServerPasswordSet2(struct pipes_struct *p,
 	confounder_len = 512 - new_password.length;
 	enc_blob = data_blob_const(r->in.new_password->data, confounder_len);
 	dec_blob = data_blob_const(password_buf.data, confounder_len);
-	if (confounder_len > 0 && data_blob_cmp(&dec_blob, &enc_blob) == 0) {
+	if (confounder_len > 0 && data_blob_cmp_const_time(&dec_blob, &enc_blob) == 0) {
 		DBG_WARNING("Confounder buffer not encrypted Length[%zu]\n",
 			    confounder_len);
 		TALLOC_FREE(creds);
@@ -1592,7 +1592,7 @@ NTSTATUS _netr_ServerPasswordSet2(struct pipes_struct *p,
 				   new_password.length);
 	dec_blob = data_blob_const(password_buf.data + confounder_len,
 				   new_password.length);
-	if (data_blob_cmp(&dec_blob, &enc_blob) == 0) {
+	if (data_blob_cmp_const_time(&dec_blob, &enc_blob) == 0) {
 		DBG_WARNING("Password buffer not encrypted Length[%zu]\n",
 			    new_password.length);
 		TALLOC_FREE(creds);
diff --git a/source3/rpc_server/samr/srv_samr_chgpasswd.c b/source3/rpc_server/samr/srv_samr_chgpasswd.c
index e326745169e..5ff3edb5eb7 100644
--- a/source3/rpc_server/samr/srv_samr_chgpasswd.c
+++ b/source3/rpc_server/samr/srv_samr_chgpasswd.c
@@ -817,7 +817,7 @@ static NTSTATUS check_oem_password(const char *user,
 				NTSTATUS status = NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER;
 				return gnutls_error_to_ntstatus(rc, status);
 			}
-			if (memcmp(verifier, old_nt_hash_encrypted, 16)) {
+			if (memcmp_const_time(verifier, old_nt_hash_encrypted, 16)) {
 				DEBUG(0, ("check_oem_password: old nt "
 					  "password doesn't match.\n"));
 				return NT_STATUS_WRONG_PASSWORD;
@@ -848,7 +848,7 @@ static NTSTATUS check_oem_password(const char *user,
 				NTSTATUS status = NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER;
 				return gnutls_error_to_ntstatus(rc, status);
 			}
-			if (memcmp(verifier, old_lm_hash_encrypted, 16)) {
+			if (memcmp_const_time(verifier, old_lm_hash_encrypted, 16)) {
 				DEBUG(0,("check_oem_password: old lm password doesn't match.\n"));
 				return NT_STATUS_WRONG_PASSWORD;
 			}
@@ -872,7 +872,7 @@ static NTSTATUS check_oem_password(const char *user,
 			NTSTATUS status = NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER;
 			return gnutls_error_to_ntstatus(rc, status);
 		}
-		if (memcmp(verifier, old_lm_hash_encrypted, 16)) {
+		if (memcmp_const_time(verifier, old_lm_hash_encrypted, 16)) {
 			DEBUG(0,("check_oem_password: old lm password doesn't match.\n"));
 			return NT_STATUS_WRONG_PASSWORD;
 		}
@@ -915,8 +915,8 @@ static bool password_in_history(uint8_t nt_pw[NT_HASH_LEN],
 			 * New format: zero salt and then plain nt hash.
 			 * Directly compare the hashes.
 			 */
-			if (memcmp(nt_pw, old_nt_pw_salted_md5_hash,
-				   SALTED_MD5_HASH_LEN) == 0)
+			if (memcmp_const_time(nt_pw, old_nt_pw_salted_md5_hash,
+					      SALTED_MD5_HASH_LEN) == 0)
 			{
 				return true;
 			}
@@ -945,9 +945,9 @@ static bool password_in_history(uint8_t nt_pw[NT_HASH_LEN],
 			}
 			gnutls_hash_deinit(hash_hnd, new_nt_pw_salted_md5_hash);
 
-			if (memcmp(new_nt_pw_salted_md5_hash,
-				   old_nt_pw_salted_md5_hash,
-				   SALTED_MD5_HASH_LEN) == 0) {
+			if (memcmp_const_time(new_nt_pw_salted_md5_hash,
+					      old_nt_pw_salted_md5_hash,
+					      SALTED_MD5_HASH_LEN) == 0) {
 				return true;
 			}
 		}
@@ -986,7 +986,7 @@ static bool check_passwd_history(struct samu *sampass, const char *plaintext)
 
 	E_md4hash(plaintext, new_nt_p16);
 
-	if (!memcmp(nt_pw, new_nt_p16, NT_HASH_LEN)) {
+	if (!memcmp_const_time(nt_pw, new_nt_p16, NT_HASH_LEN)) {
 		DEBUG(10,("check_passwd_history: proposed new password for user %s is the same as the current password !\n",
 			pdb_get_username(sampass) ));
 		return True;
diff --git a/source3/winbindd/winbindd_dual_srv.c b/source3/winbindd/winbindd_dual_srv.c
index bb164d9914a..59564798ded 100644
--- a/source3/winbindd/winbindd_dual_srv.c
+++ b/source3/winbindd/winbindd_dual_srv.c
@@ -1536,12 +1536,12 @@ reconnect:
 		}
 	}
 
-	cmp_new = memcmp(new_owf_password.hash,
-			 cur_nt_hash->hash,
-			 sizeof(cur_nt_hash->hash));
-	cmp_old = memcmp(old_owf_password.hash,
-			 cur_nt_hash->hash,
-			 sizeof(cur_nt_hash->hash));
+	cmp_new = memcmp_const_time(new_owf_password.hash,
+				    cur_nt_hash->hash,
+				    sizeof(cur_nt_hash->hash));
+	cmp_old = memcmp_const_time(old_owf_password.hash,
+				    cur_nt_hash->hash,
+				    sizeof(cur_nt_hash->hash));
 	if (cmp_new != 0 && cmp_old != 0) {
 		DEBUG(1,("%s:Error: credentials for domain[%s/%s] doesn't match "
 			 "any password known to dcname[%s]\n",
diff --git a/source3/winbindd/winbindd_pam.c b/source3/winbindd/winbindd_pam.c
index 21649c69b10..b8c9fb67a65 100644
--- a/source3/winbindd/winbindd_pam.c
+++ b/source3/winbindd/winbindd_pam.c
@@ -1215,12 +1215,12 @@ static NTSTATUS winbindd_dual_pam_auth_cached(struct winbindd_domain *domain,
 		}
 		gnutls_hash_deinit(hash_hnd, salted_hash);
 
-		password_good = (memcmp(cached_nt_pass, salted_hash,
-					NT_HASH_LEN) == 0);
+		password_good = (memcmp_const_time(cached_nt_pass, salted_hash,
+						   NT_HASH_LEN) == 0);
 	} else {
 		/* Old cached cred - direct store of nt_hash (bad bad bad !). */
-		password_good = (memcmp(cached_nt_pass, new_nt_pass,
-					NT_HASH_LEN) == 0);
+		password_good = (memcmp_const_time(cached_nt_pass, new_nt_pass,
+						   NT_HASH_LEN) == 0);
 	}
 
 	if (password_good) {
diff --git a/source4/auth/ntlm/auth_sam.c b/source4/auth/ntlm/auth_sam.c
index 14b6c707aa5..1bbf6c3fd16 100644
--- a/source4/auth/ntlm/auth_sam.c
+++ b/source4/auth/ntlm/auth_sam.c
@@ -364,7 +364,7 @@ static NTSTATUS authsam_password_check_and_record(struct auth4_context *auth_con
 		 */
 
 		E_md4hash("", zero_string_hash.hash);
-		if (memcmp(nt_history_pwd->hash, zero_string_hash.hash, 16) == 0) {
+		if (memcmp_const_time(nt_history_pwd->hash, zero_string_hash.hash, 16) == 0) {
 			continue;
 		}
 
diff --git a/source4/dsdb/samdb/ldb_modules/password_hash.c b/source4/dsdb/samdb/ldb_modules/password_hash.c
index faf8a35818f..1b194799b9f 100644
--- a/source4/dsdb/samdb/ldb_modules/password_hash.c
+++ b/source4/dsdb/samdb/ldb_modules/password_hash.c
@@ -601,7 +601,7 @@ static int password_hash_bypass(struct ldb_module *module, struct ldb_request *r
 					 "supplementalCredentialsBlob length differ");
 		}
 
-		if (memcmp(sce->values[0].data, blob.data, blob.length) != 0) {
+		if (memcmp_const_time(sce->values[0].data, blob.data, blob.length) != 0) {
 			return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION,
 					 "supplementalCredentialsBlob memcmp differ");
 		}
@@ -2754,7 +2754,7 @@ static int check_password_restrictions(struct setup_password_fields_io *io, WERR
 
 		/* The password modify through the NT hash is encouraged and
 		   has no problems at all */
-		if (!io->o.nt_hash || memcmp(io->og.nt_hash->hash, io->o.nt_hash->hash, 16) != 0) {
+		if (!io->o.nt_hash || memcmp_const_time(io->og.nt_hash->hash, io->o.nt_hash->hash, 16) != 0) {
 			return make_error_and_update_badPwdCount(io, werror);
 		}
 	}
@@ -2842,7 +2842,7 @@ static int check_password_restrictions(struct setup_password_fields_io *io, WERR
 
 		/* checks the NT hash password history */
 		for (i = 0; i < io->o.nt_history_len; i++) {
-			int pw_cmp = memcmp(io->n.nt_hash, io->o.nt_history[i].hash, 16);
+			int pw_cmp = memcmp_const_time(io->n.nt_hash, io->o.nt_history[i].hash, 16);
 			if (pw_cmp == 0) {
 				ret = LDB_ERR_CONSTRAINT_VIOLATION;
 				*werror = WERR_PASSWORD_RESTRICTION;
diff --git a/source4/libcli/raw/smb_signing.c b/source4/libcli/raw/smb_signing.c
index 40734cb7205..cd781506897 100644
--- a/source4/libcli/raw/smb_signing.c
+++ b/source4/libcli/raw/smb_signing.c
@@ -198,7 +198,7 @@ bool check_signed_incoming_message(struct smb_request_buffer *in, DATA_BLOB *mac
 
 		gnutls_hash_deinit(hash_hnd, calc_md5_mac);
 
-		ok = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
+		ok = (memcmp_const_time(server_sent_mac, calc_md5_mac, 8) == 0);
 
 		if (i == 0) {
 			if (!ok) {
diff --git a/source4/rpc_server/backupkey/dcesrv_backupkey.c b/source4/rpc_server/backupkey/dcesrv_backupkey.c
index 181f95a5918..5fbd36323e4 100644
--- a/source4/rpc_server/backupkey/dcesrv_backupkey.c
+++ b/source4/rpc_server/backupkey/dcesrv_backupkey.c
@@ -451,7 +451,7 @@ static WERROR get_and_verify_access_check(TALLOC_CTX *sub_ctx,
 		 * point to the same area
 		 */
 
-		if (memcmp(hash, uncrypted_accesscheckv2.hash, hash_size) != 0) {
+		if (memcmp_const_time(hash, uncrypted_accesscheckv2.hash, hash_size) != 0) {
 			DEBUG(2, ("Wrong hash value in the access check in backup key remote protocol\n"));
 			return WERR_INVALID_DATA;
 		}
@@ -486,7 +486,7 @@ static WERROR get_and_verify_access_check(TALLOC_CTX *sub_ctx,
 		 * point to the same area
 		 */
 
-		if (memcmp(hash, uncrypted_accesscheckv3.hash, hash_size) != 0) {
+		if (memcmp_const_time(hash, uncrypted_accesscheckv3.hash, hash_size) != 0) {
 			DEBUG(2, ("Wrong hash value in the access check in backup key remote protocol\n"));
 			return WERR_INVALID_DATA;
 		}
@@ -1547,7 +1547,7 @@ static WERROR bkrp_server_wrap_decrypt_data(struct dcesrv_call_state *dce_call,
 	dump_data_pw("mac: \n", mac, sizeof(mac));
 	dump_data_pw("rc4payload.mac: \n", rc4payload.mac, sizeof(rc4payload.mac));
 
-	if (memcmp(mac, rc4payload.mac, sizeof(mac)) != 0) {
+	if (memcmp_const_time(mac, rc4payload.mac, sizeof(mac)) != 0) {
 		return WERR_INVALID_ACCESS;
 	}
 
diff --git a/source4/rpc_server/netlogon/dcerpc_netlogon.c b/source4/rpc_server/netlogon/dcerpc_netlogon.c
index 062a92597ce..7978b20555c 100644
--- a/source4/rpc_server/netlogon/dcerpc_netlogon.c
+++ b/source4/rpc_server/netlogon/dcerpc_netlogon.c
@@ -873,7 +873,7 @@ static NTSTATUS dcesrv_netr_ServerPasswordSet2(struct dcesrv_call_state *dce_cal
 	confounder_len = 512 - new_password.length;
 	enc_blob = data_blob_const(r->in.new_password->data, confounder_len);
 	dec_blob = data_blob_const(password_buf.data, confounder_len);
-	if (confounder_len > 0 && data_blob_cmp(&dec_blob, &enc_blob) == 0) {
+	if (confounder_len > 0 && data_blob_cmp_const_time(&dec_blob, &enc_blob) == 0) {
 		DBG_WARNING("Confounder buffer not encrypted Length[%zu]\n",
 			    confounder_len);
 		return NT_STATUS_WRONG_PASSWORD;
@@ -887,7 +887,7 @@ static NTSTATUS dcesrv_netr_ServerPasswordSet2(struct dcesrv_call_state *dce_cal
 				   new_password.length);
 	dec_blob = data_blob_const(password_buf.data + confounder_len,
 				   new_password.length);
-	if (data_blob_cmp(&dec_blob, &enc_blob) == 0) {
+	if (data_blob_cmp_const_time(&dec_blob, &enc_blob) == 0) {
 		DBG_WARNING("Password buffer not encrypted Length[%zu]\n",
 			    new_password.length);
 		return NT_STATUS_WRONG_PASSWORD;
diff --git a/source4/rpc_server/samr/samr_password.c b/source4/rpc_server/samr/samr_password.c
index 0107c98da75..7dfde68b0d7 100644
--- a/source4/rpc_server/samr/samr_password.c
+++ b/source4/rpc_server/samr/samr_password.c
@@ -240,7 +240,7 @@ NTSTATUS dcesrv_samr_ChangePasswordUser3(struct dcesrv_call_state *dce_call,
 		status = gnutls_error_to_ntstatus(rc, NT_STATUS_ACCESS_DISABLED_BY_POLICY_OTHER);
 		goto failed;
 	}
-	if (memcmp(nt_verifier.hash, r->in.nt_verifier->hash, 16) != 0) {
+	if (memcmp_const_time(nt_verifier.hash, r->in.nt_verifier->hash, 16) != 0) {
 		status = NT_STATUS_WRONG_PASSWORD;
 		goto failed;
 	}