From acff29e6f269a96e071cfb3a3df21db14e087ce2 Mon Sep 17 00:00:00 2001
From: ccli8 <ccli8@nuvoton.com>
Date: Thu, 21 Dec 2017 16:05:55 +0800
Subject: [PATCH] [NUC472/M487] Fix context clone corner case in SHA alter.

As destination/source contexts are the same, we return immediately.
---
 .../targets/TARGET_NUVOTON/TARGET_M480/sha/sha1_alt.c        | 5 +++++
 .../targets/TARGET_NUVOTON/TARGET_M480/sha/sha256_alt.c      | 5 +++++
 .../targets/TARGET_NUVOTON/TARGET_M480/sha/sha512_alt.c      | 5 +++++
 .../targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha1_alt.c      | 5 +++++
 .../targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha256_alt.c    | 5 +++++
 5 files changed, 25 insertions(+)

diff --git a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha1_alt.c b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha1_alt.c
index 761c8c33d9..35d7122610 100644
--- a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha1_alt.c
+++ b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha1_alt.c
@@ -63,6 +63,11 @@ void mbedtls_sha1_free(mbedtls_sha1_context *ctx)
 void mbedtls_sha1_clone(mbedtls_sha1_context *dst,
                         const mbedtls_sha1_context *src)
 {
+    // Corner case: Destination/source contexts are the same
+    if (dst == src) {
+        return;
+    }
+
     // If dst is H/W context, we need to change it to S/W context first before cloning to.
     if (dst->active_ctx == &dst->hw_ctx) {
         mbedtls_sha1_free(dst);
diff --git a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha256_alt.c b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha256_alt.c
index 09ec8e4335..c4e27dfa5f 100644
--- a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha256_alt.c
+++ b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha256_alt.c
@@ -63,6 +63,11 @@ void mbedtls_sha256_free(mbedtls_sha256_context *ctx)
 void mbedtls_sha256_clone(mbedtls_sha256_context *dst,
                           const mbedtls_sha256_context *src)
 {
+    // Corner case: Destination/source contexts are the same
+    if (dst == src) {
+        return;
+    }
+
     // If dst is H/W context, we need to change it to S/W context first before cloning to.
     if (dst->active_ctx == &dst->hw_ctx) {
         mbedtls_sha256_free(dst);
diff --git a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha512_alt.c b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha512_alt.c
index ce25a5e861..48baf9132f 100644
--- a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha512_alt.c
+++ b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_M480/sha/sha512_alt.c
@@ -63,6 +63,11 @@ void mbedtls_sha512_free(mbedtls_sha512_context *ctx)
 void mbedtls_sha512_clone(mbedtls_sha512_context *dst,
                           const mbedtls_sha512_context *src)
 {
+    // Corner case: Destination/source contexts are the same
+    if (dst == src) {
+        return;
+    }
+
     // If dst is H/W context, we need to change it to S/W context first before cloning to.
     if (dst->active_ctx == &dst->hw_ctx) {
         mbedtls_sha512_free(dst);
diff --git a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha1_alt.c b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha1_alt.c
index 761c8c33d9..35d7122610 100644
--- a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha1_alt.c
+++ b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha1_alt.c
@@ -63,6 +63,11 @@ void mbedtls_sha1_free(mbedtls_sha1_context *ctx)
 void mbedtls_sha1_clone(mbedtls_sha1_context *dst,
                         const mbedtls_sha1_context *src)
 {
+    // Corner case: Destination/source contexts are the same
+    if (dst == src) {
+        return;
+    }
+
     // If dst is H/W context, we need to change it to S/W context first before cloning to.
     if (dst->active_ctx == &dst->hw_ctx) {
         mbedtls_sha1_free(dst);
diff --git a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha256_alt.c b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha256_alt.c
index 57ed6d5b3c..b576d7a767 100644
--- a/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha256_alt.c
+++ b/features/mbedtls/targets/TARGET_NUVOTON/TARGET_NUC472/sha/sha256_alt.c
@@ -63,6 +63,11 @@ void mbedtls_sha256_free(mbedtls_sha256_context *ctx)
 void mbedtls_sha256_clone(mbedtls_sha256_context *dst,
                           const mbedtls_sha256_context *src)
 {
+    // Corner case: Destination/source contexts are the same
+    if (dst == src) {
+        return;
+    }
+
     // If dst is H/W context, we need to change it to S/W context first before cloning to.
     if (dst->active_ctx == &dst->hw_ctx) {
         mbedtls_sha256_free(dst);