From b6473792c0158e1b7d1eb489e8f1b37e34d8dcb5 Mon Sep 17 00:00:00 2001
From: David Garske <david@wolfssl.com>
Date: Tue, 28 Nov 2023 09:59:27 -0800
Subject: [PATCH] Cleanup KDF function return code checking to avoid scan-build
 warning.

---
 src/tpm2_param_enc.c | 41 +++++++++++++++++------------------------
 src/tpm2_wrap.c      | 27 +++++++++++----------------
 2 files changed, 28 insertions(+), 40 deletions(-)

diff --git a/src/tpm2_param_enc.c b/src/tpm2_param_enc.c
index 8d315b9..f72a2e7 100644
--- a/src/tpm2_param_enc.c
+++ b/src/tpm2_param_enc.c
@@ -103,7 +103,7 @@ int TPM2_KDFa(
         return NOT_COMPILED_IN;
 
     hLen = TPM2_GetHashDigestSize(hashAlg);
-    if ( (hLen <= 0) || (hLen > WC_MAX_DIGEST_SIZE))
+    if ((hLen <= 0) || (hLen > WC_MAX_DIGEST_SIZE))
         return NOT_COMPILED_IN;
 
     /* get label length if provided, including null termination */
@@ -128,46 +128,39 @@ int TPM2_KDFa(
         else {
             ret = wc_HmacSetKey(&hmac_ctx, hashType, NULL, 0);
         }
-        if (ret != 0)
-            goto exit;
-
         /* add counter - KDFa i2 */
-        TPM2_Packet_U32ToByteArray(counter, uint32Buf);
-        ret = wc_HmacUpdate(&hmac_ctx, uint32Buf, (word32)sizeof(uint32Buf));
-        if (ret != 0)
-            goto exit;
-
+        if (ret == 0) {
+            TPM2_Packet_U32ToByteArray(counter, uint32Buf);
+            ret = wc_HmacUpdate(&hmac_ctx, uint32Buf, (word32)sizeof(uint32Buf));
+        }
         /* add label - KDFa label */
-        if (label != NULL) {
+        if (ret == 0 && label != NULL) {
             ret = wc_HmacUpdate(&hmac_ctx, (byte*)label, lLen);
-            if (ret != 0)
-                goto exit;
         }
 
         /* add contextU */
-        if (contextU != NULL && contextU->size > 0) {
+        if (ret == 0 && contextU != NULL && contextU->size > 0) {
             ret = wc_HmacUpdate(&hmac_ctx, contextU->buffer, contextU->size);
-            if (ret != 0)
-                goto exit;
         }
 
         /* add contextV */
-        if (contextV != NULL && contextV->size > 0) {
+        if (ret == 0 && contextV != NULL && contextV->size > 0) {
             ret = wc_HmacUpdate(&hmac_ctx, contextV->buffer, contextV->size);
-            if (ret != 0)
-                goto exit;
         }
 
         /* add size in bits */
-        TPM2_Packet_U32ToByteArray(sizeInBits, uint32Buf);
-        ret = wc_HmacUpdate(&hmac_ctx, uint32Buf, (word32)sizeof(uint32Buf));
-        if (ret != 0)
-            goto exit;
+        if (ret == 0) {
+            TPM2_Packet_U32ToByteArray(sizeInBits, uint32Buf);
+            ret = wc_HmacUpdate(&hmac_ctx, uint32Buf, (word32)sizeof(uint32Buf));
+        }
 
         /* get result */
-        ret = wc_HmacFinal(&hmac_ctx, hash);
-        if (ret != 0)
+        if (ret == 0) {
+            ret = wc_HmacFinal(&hmac_ctx, hash);
+        }
+        if (ret != 0) {
             goto exit;
+        }
 
         if ((UINT32)hLen > keySz - pos) {
           copyLen = keySz - pos;
diff --git a/src/tpm2_wrap.c b/src/tpm2_wrap.c
index b64f998..2b3efa0 100644
--- a/src/tpm2_wrap.c
+++ b/src/tpm2_wrap.c
@@ -999,7 +999,7 @@ static int TPM2_KDFe(
     hashType = (enum wc_HashType)ret;
 
     hLen = TPM2_GetHashDigestSize(hashAlg);
-    if ( (hLen <= 0) || (hLen > WC_MAX_DIGEST_SIZE))
+    if ((hLen <= 0) || (hLen > WC_MAX_DIGEST_SIZE))
         return NOT_COMPILED_IN;
 
     /* get label length if provided, including null termination */
@@ -1021,37 +1021,32 @@ static int TPM2_KDFe(
         TPM2_Packet_U32ToByteArray(counter, uint32Buf);
         ret = wc_HashUpdate(&hash_ctx, hashType, uint32Buf,
             (word32)sizeof(uint32Buf));
-        if (ret != 0)
-            goto exit;
-
         /* add Z */
-        ret = wc_HashUpdate(&hash_ctx, hashType, Z->buffer, Z->size);
-
+        if (ret == 0) {
+            ret = wc_HashUpdate(&hash_ctx, hashType, Z->buffer, Z->size);
+        }
         /* add label */
-        if (label != NULL) {
+        if (ret == 0 && label != NULL) {
             ret = wc_HashUpdate(&hash_ctx, hashType, (byte*)label, lLen);
-            if (ret != 0)
-                goto exit;
         }
 
         /* add partyUInfo */
-        if (partyUInfo != NULL && partyUInfo->size > 0) {
+        if (ret == 0 && partyUInfo != NULL && partyUInfo->size > 0) {
             ret = wc_HashUpdate(&hash_ctx, hashType, partyUInfo->buffer,
                 partyUInfo->size);
-            if (ret != 0)
-                goto exit;
         }
 
         /* add partyVInfo */
-        if (partyVInfo != NULL && partyVInfo->size > 0) {
+        if (ret == 0 && partyVInfo != NULL && partyVInfo->size > 0) {
             ret = wc_HashUpdate(&hash_ctx, hashType, partyVInfo->buffer,
                 partyVInfo->size);
-            if (ret != 0)
-                goto exit;
         }
 
         /* get result */
-        ret = wc_HashFinal(&hash_ctx, hashType, hash);
+        if (ret == 0) {
+            ret = wc_HashFinal(&hash_ctx, hashType, hash);
+        }
+
         if (ret != 0)
             goto exit;