From cedec3ae28d1bb2177604b5668c6709946fa77d5 Mon Sep 17 00:00:00 2001
From: Tesfa Mael <tesfa@wolfssl.com>
Date: Mon, 28 Dec 2020 15:53:56 -0800
Subject: [PATCH 1/2] Add parameter check

---
 wolfcrypt/src/random.c | 2 +-
 wolfcrypt/src/sp_int.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/wolfcrypt/src/random.c b/wolfcrypt/src/random.c
index e8070a355..05ad76c7b 100644
--- a/wolfcrypt/src/random.c
+++ b/wolfcrypt/src/random.c
@@ -914,7 +914,7 @@ int wc_RNG_GenerateBlock(WC_RNG* rng, byte* output, word32 sz)
 {
     int ret;
 
-    if (rng == NULL || output == NULL)
+    if (rng == NULL || output == NULL || sz == 0 )
         return BAD_FUNC_ARG;
 
 #ifdef WOLF_CRYPTO_CB
diff --git a/wolfcrypt/src/sp_int.c b/wolfcrypt/src/sp_int.c
index 53fe07a11..7e436caef 100644
--- a/wolfcrypt/src/sp_int.c
+++ b/wolfcrypt/src/sp_int.c
@@ -12979,7 +12979,7 @@ int sp_rand_prime(sp_int* r, int len, WC_RNG* rng, void* heap)
 
     (void)heap;
 
-    if ((r == NULL) || (rng == NULL)) {
+    if ((r == NULL) || (rng == NULL) || len <= 0 ) {
         err = MP_VAL;
     }
 

From d366ca74af7ce37690a3e4fffb7bcac1f06c9d66 Mon Sep 17 00:00:00 2001
From: Tesfa Mael <tesfa@wolfssl.com>
Date: Tue, 29 Dec 2020 19:48:45 -0800
Subject: [PATCH 2/2] Review comments and cast

---
 wolfcrypt/src/random.c | 5 ++++-
 wolfcrypt/src/sp_int.c | 7 +++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/wolfcrypt/src/random.c b/wolfcrypt/src/random.c
index 05ad76c7b..bd8a2142a 100644
--- a/wolfcrypt/src/random.c
+++ b/wolfcrypt/src/random.c
@@ -914,9 +914,12 @@ int wc_RNG_GenerateBlock(WC_RNG* rng, byte* output, word32 sz)
 {
     int ret;
 
-    if (rng == NULL || output == NULL || sz == 0 )
+    if (rng == NULL || output == NULL)
         return BAD_FUNC_ARG;
 
+    if (sz == 0)
+        return 0; 
+
 #ifdef WOLF_CRYPTO_CB
     if (rng->devId != INVALID_DEVID) {
         ret = wc_CryptoCb_RandomBlock(rng, output, sz);
diff --git a/wolfcrypt/src/sp_int.c b/wolfcrypt/src/sp_int.c
index 7e436caef..d81fd98e8 100644
--- a/wolfcrypt/src/sp_int.c
+++ b/wolfcrypt/src/sp_int.c
@@ -9240,7 +9240,7 @@ int sp_div_2d(sp_int* a, int e, sp_int* r, sp_int* rem)
                 rem->used = (e + SP_WORD_SIZE - 1) >> SP_WORD_SHIFT;
                 e &= SP_WORD_MASK;
                 if (e > 0) {
-                    rem->dp[rem->used - 1] &= (1 << e) - 1;
+                    rem->dp[rem->used - 1] &= ((sp_int_digit)1 << e) - 1;
                 }
                 sp_clamp(rem);
             }
@@ -12979,10 +12979,13 @@ int sp_rand_prime(sp_int* r, int len, WC_RNG* rng, void* heap)
 
     (void)heap;
 
-    if ((r == NULL) || (rng == NULL) || len <= 0 ) {
+    if ((r == NULL) || (rng == NULL) || len < 0 ) {
         err = MP_VAL;
     }
 
+    if (len == 0)
+        return MP_OKAY;
+
     if (err == MP_OKAY) {
         /* get type */
         if (len < 0) {