From ebffb48cd3a1e063f9353e75e44b893d892484d8 Mon Sep 17 00:00:00 2001
From: pscott <scott.piriou@ledger.fr>
Date: Wed, 28 Apr 2021 10:48:18 +0200
Subject: [PATCH] Use snprintf instead of u32_to_str

---
 src/utils.c                        | 39 ------------------------------
 src/utils.h                        |  3 ---
 src_features/signTx/logic_signTx.c |  8 +++++-
 3 files changed, 7 insertions(+), 43 deletions(-)

diff --git a/src/utils.c b/src/utils.c
index 9c16b6f..b319736 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -72,45 +72,6 @@ uint32_t u32_from_BE(uint8_t *in, uint8_t size, bool strict) {
     return res;
 }
 
-// Converts a uint32_t to a string.
-void u32_to_str(char *dest, uint32_t in, uint8_t dest_size) {
-    uint8_t i = 0;
-
-    // Get the first digit (in case it's 0).
-    dest[i] = in % 10 + '0';
-    in /= 10;
-    i++;
-
-    // Get every digit.
-    while (in != 0) {
-        if (i >= dest_size) {
-            THROW(6502);
-        }
-        dest[i] = in % 10 + '0';
-        in /= 10;
-        i++;
-    }
-
-    // Null terminate the string.
-    dest[i] = '\0';
-    i--;
-
-    // Reverse the string
-    uint8_t end = i;
-    char tmp;
-    i = 0;
-    while (i < end) {
-        // Swap the first and last elements.
-        tmp = dest[i];
-        dest[i] = dest[end];
-        dest[end] = tmp;
-
-        // Decrease the interval size.
-        i++;
-        end--;
-    }
-}
-
 void amountToString(uint8_t *amount,
                     uint8_t amount_size,
                     uint8_t decimals,
diff --git a/src/utils.h b/src/utils.h
index b7d3118..ba878e1 100644
--- a/src/utils.h
+++ b/src/utils.h
@@ -28,9 +28,6 @@ void convertUint256BE(uint8_t* data, uint32_t length, uint256_t* target);
 
 int local_strchr(char* string, char ch);
 
-// `itoa` for uint32_t.
-void u32_to_str(char* dest, uint8_t dest_size, uint32_t in);
-
 // Converts a list of bytes (in BE) of length `size` to a uint32_t. `strict` will make the function
 // throw if the size is > 4.
 uint32_t u32_from_BE(uint8_t* in, uint8_t size, bool strict);
diff --git a/src_features/signTx/logic_signTx.c b/src_features/signTx/logic_signTx.c
index 002f21e..9a5dc42 100644
--- a/src_features/signTx/logic_signTx.c
+++ b/src_features/signTx/logic_signTx.c
@@ -389,7 +389,13 @@ void finalizeParsing(bool direct) {
     if (genericUI) {
         if (txContext.txType == LEGACY) {
             uint32_t id = u32_from_BE(txContext.content->v, txContext.content->vLength, true);
-            u32_to_str((char *) strings.common.chainID, sizeof(strings.common.chainID), id);
+            uint8_t res =
+                snprintf(strings.common.chainID, sizeof(strings.common.chainID), "%u", id);
+            if (res >= sizeof(strings.common.chainID)) {
+                // If the return value is higher or equal to the size passed in as parameter, then
+                // the output was truncated. Return the appropriate error code.
+                THROW(0x6502);
+            }
         } else if (txContext.txType == EIP2930) {
             uint256_t chainID;
             convertUint256BE(tmpContent.txContent.chainID.value,