lib/util: Change function to mem_equal_const_time()

Since memcmp_const_time() doesn't act as an exact replacement for
memcmp(), and its return value is only ever compared with zero, simplify
it and emphasize the intention of checking equality by returning a bool
instead.

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

4 files changed, 13 insertions, 13 deletions

diff --git a/auth/gensec/schannel.c b/auth/gensec/schannel.c
index 2fbfb019124..9860559668f 100644
--- a/auth/gensec/schannel.c
+++ b/auth/gensec/schannel.c
@@ -592,7 +592,7 @@ static NTSTATUS netsec_incoming_packet(struct schannel_state *state,
 	uint8_t *confounder = NULL;
 	uint32_t confounder_ofs = 0;
 	uint8_t seq_num[8];
-	int ret;
+	bool ret;
 	const uint8_t *sign_data = NULL;
 	size_t sign_length = 0;
 	NTSTATUS status;
@@ -649,8 +649,8 @@ static NTSTATUS netsec_incoming_packet(struct schannel_state *state,
 		return NT_STATUS_ACCESS_DENIED;
 	}
 
-	ret = memcmp_const_time(checksum, sig->data+16, checksum_length);
-	if (ret != 0) {
+	ret = mem_equal_const_time(checksum, sig->data+16, checksum_length);
+	if (!ret) {
 		dump_data_pw("calc digest:", checksum, checksum_length);
 		dump_data_pw("wire digest:", sig->data+16, checksum_length);
 		return NT_STATUS_ACCESS_DENIED;
@@ -665,8 +665,8 @@ static NTSTATUS netsec_incoming_packet(struct schannel_state *state,
 
 	ZERO_ARRAY(checksum);
 
-	ret = memcmp_const_time(seq_num, sig->data+8, 8);
-	if (ret != 0) {
+	ret = mem_equal_const_time(seq_num, sig->data+8, 8);
+	if (!ret) {
 		dump_data_pw("calc seq num:", seq_num, 8);
 		dump_data_pw("wire seq num:", sig->data+8, 8);
 		return NT_STATUS_ACCESS_DENIED;
diff --git a/auth/ntlmssp/ntlmssp_ndr.c b/auth/ntlmssp/ntlmssp_ndr.c
index 6de00427bbd..ea5d6f0f5a0 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_const_time(r->Signature, "NTLMSSP\0", 8)) { \
+	if (!mem_equal_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 55688602881..6a27db1b7d4 100644
--- a/auth/ntlmssp/ntlmssp_server.c
+++ b/auth/ntlmssp/ntlmssp_server.c
@@ -1047,7 +1047,7 @@ static NTSTATUS ntlmssp_server_postauth(struct gensec_security *gensec_security,
 	if (ntlmssp_state->new_spnego) {
 		gnutls_hmac_hd_t hmac_hnd = NULL;
 		uint8_t mic_buffer[NTLMSSP_MIC_SIZE] = { 0, };
-		int cmp;
+		bool cmp;
 		int rc;
 
 		rc = gnutls_hmac_init(&hmac_hnd,
@@ -1095,9 +1095,9 @@ static NTSTATUS ntlmssp_server_postauth(struct gensec_security *gensec_security,
 		}
 		gnutls_hmac_deinit(hmac_hnd, mic_buffer);
 
-		cmp = memcmp_const_time(request.data + NTLMSSP_MIC_OFFSET,
-					mic_buffer, NTLMSSP_MIC_SIZE);
-		if (cmp != 0) {
+		cmp = mem_equal_const_time(request.data + NTLMSSP_MIC_OFFSET,
+					   mic_buffer, NTLMSSP_MIC_SIZE);
+		if (!cmp) {
 			DEBUG(1,("%s: invalid NTLMSSP_MIC for "
 				 "user=[%s] domain=[%s] workstation=[%s]\n",
 				 __func__,
@@ -1112,7 +1112,7 @@ static NTSTATUS ntlmssp_server_postauth(struct gensec_security *gensec_security,
 
 		ZERO_ARRAY(mic_buffer);
 
-		if (cmp != 0) {
+		if (!cmp) {
 			return NT_STATUS_INVALID_PARAMETER;
 		}
 	}
diff --git a/auth/ntlmssp/ntlmssp_sign.c b/auth/ntlmssp/ntlmssp_sign.c
index b831308aa2c..11e5930a8de 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_const_time(local_sig.data, sig->data, sig->length) != 0) {
+		    !mem_equal_const_time(local_sig.data, sig->data, sig->length)) {
 			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_const_time(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
+		    !mem_equal_const_time(local_sig.data + 8, sig->data + 8, sig->length - 8)) {
 			DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
 			dump_data(5, local_sig.data, local_sig.length);