Fixes to compiler warnings in MSVC

firmware/lib/cryptolib/rsa.c

Index: firmware/lib/cryptolib/rsa.c
diff --git a/firmware/lib/cryptolib/rsa.c b/firmware/lib/cryptolib/rsa.c
index bfc644690e615d64c2f068bb1bef123afd6f32c2..930d91b4a332e6ffb14c9ec228b559478c408000 100644
--- a/firmware/lib/cryptolib/rsa.c
+++ b/firmware/lib/cryptolib/rsa.c
@@ -14,7 +14,7 @@
 /* a[] -= mod */
 static void subM(const RSAPublicKey *key, uint32_t *a) {
   int64_t A = 0;
-  int i;
+  uint32_t i;
   for (i = 0; i < key->len; ++i) {
     A += (uint64_t)a[i] - key->n[i];
     a[i] = (uint32_t)A;
@@ -24,7 +24,7 @@ static void subM(const RSAPublicKey *key, uint32_t *a) {
 
 /* return a[] >= mod */
 static int geM(const RSAPublicKey *key, uint32_t *a) {
-  int i;
+  uint32_t i;
   for (i = key->len; i;) {
     --i;
     if (a[i] < key->n[i]) return 0;
@@ -38,14 +38,14 @@ static void montMulAdd(const RSAPublicKey *key,
                        uint32_t* c,
                        const uint32_t a,
                        const uint32_t* b) {
-  uint64_t A = (uint64_t)a * b[0] + c[0];
+  uint64_t A = UINT64_MULT32(a, b[0]) + c[0];
   uint32_t d0 = (uint32_t)A * key->n0inv;
-  uint64_t B = (uint64_t)d0 * key->n[0] + (uint32_t)A;
-  int i;
+  uint64_t B = UINT64_MULT32(d0, key->n[0]) + (uint32_t)A;
+  uint32_t i;
 
   for (i = 1; i < key->len; ++i) {
-    A = (A >> 32) + (uint64_t)a * b[i] + c[i];
-    B = (B >> 32) + (uint64_t)d0 * key->n[i] + (uint32_t)A;
+    A = (A >> 32) + UINT64_MULT32(a, b[i]) + c[i];
+    B = (B >> 32) + UINT64_MULT32(d0, key->n[i]) + (uint32_t)A;
     c[i - 1] = (uint32_t)B;
   }
 
@@ -63,7 +63,7 @@ static void montMul(const RSAPublicKey *key,
                     uint32_t* c,
                     uint32_t* a,
                     uint32_t* b) {
-  int i;
+  uint32_t i;
   for (i = 0; i < key->len; ++i) {
     c[i] = 0;
   }
@@ -85,7 +85,7 @@ static void modpowF4(const RSAPublicKey *key,
   int i;
 
   /* Convert from big endian byte array to little endian word array. */
-  for (i = 0; i < key->len; ++i) {
+  for (i = 0; i < (int)key->len; ++i) {

[gauravsh, 2010/06/21 23:32:48]

both i and key->len are uint32_t, so this cast seems unncessary

[Randall Spangler, 2010/06/21 23:58:05]

i is a (signed) int; key->len is a uint32_t.  So MSVC gives a signed/unsigned
comparison warning.

     uint32_t tmp =
         (inout[((key->len - 1 - i) * 4) + 0] << 24) |
         (inout[((key->len - 1 - i) * 4) + 1] << 16) |
@@ -108,12 +108,12 @@ static void modpowF4(const RSAPublicKey *key,
   }
 
   /* Convert to bigendian byte array */
-  for (i = key->len - 1; i >= 0; --i) {
+  for (i = (int)key->len - 1; i >= 0; --i) {

[gauravsh, 2010/06/21 23:32:48]

i and key->len are both uint32_t

     uint32_t tmp = aaa[i];
-    *inout++ = tmp >> 24;
-    *inout++ = tmp >> 16;
-    *inout++ = tmp >> 8;
-    *inout++ = tmp >> 0;
+    *inout++ = (uint8_t)(tmp >> 24);
+    *inout++ = (uint8_t)(tmp >> 16);
+    *inout++ = (uint8_t)(tmp >>  8);
+    *inout++ = (uint8_t)(tmp >>  0);
   }
 
   Free(a);
@@ -126,7 +126,7 @@ static void modpowF4(const RSAPublicKey *key,
  */
 int RSAVerify(const RSAPublicKey *key,
               const uint8_t *sig,
-              const int sig_len,
+              const uint32_t sig_len,
               const uint8_t sig_type,
               const uint8_t *hash) {
   int i;