[am43][lightwaverf][rf_bridge][spi_led_strip] Replace sprintf with safe alternatives (#13302)

esphome/components/am43/am43_base.cpp

@@ -1,21 +1,12 @@
 #include "am43_base.h"
+#include "esphome/core/helpers.h"
 #include <cstring>
-#include <cstdio>
 
 namespace esphome {
 namespace am43 {
 
 const uint8_t START_PACKET[5] = {0x00, 0xff, 0x00, 0x00, 0x9a};
 
-std::string pkt_to_hex(const uint8_t *data, uint16_t len) {
-  char buf[64];
-  memset(buf, 0, 64);
-  for (int i = 0; i < len; i++)
-    sprintf(&buf[i * 2], "%02x", data[i]);
-  std::string ret = buf;
-  return ret;
-}
-
 Am43Packet *Am43Encoder::get_battery_level_request() {
   uint8_t data = 0x1;
   return this->encode_(0xA2, &data, 1);
@@ -73,7 +64,9 @@ Am43Packet *Am43Encoder::encode_(uint8_t command, uint8_t *data, uint8_t length)
   memcpy(&this->packet_.data[7], data, length);
   this->packet_.length = length + 7;
   this->checksum_();
-  ESP_LOGV("am43", "ENC(%d): 0x%s", packet_.length, pkt_to_hex(packet_.data, packet_.length).c_str());
+  char hex_buf[format_hex_size(sizeof(this->packet_.data))];
+  ESP_LOGV("am43", "ENC(%d): 0x%s", this->packet_.length,
+           format_hex_to(hex_buf, this->packet_.data, this->packet_.length));
   return &this->packet_;
 }
 
@@ -88,7 +81,8 @@ void Am43Decoder::decode(const uint8_t *data, uint16_t length) {
   this->has_set_state_response_ = false;
   this->has_position_ = false;
   this->has_pin_response_ = false;
-  ESP_LOGV("am43", "DEC(%d): 0x%s", length, pkt_to_hex(data, length).c_str());
+  char hex_buf[format_hex_size(24)];  // Max expected packet size
+  ESP_LOGV("am43", "DEC(%d): 0x%s", length, format_hex_to(hex_buf, data, length));
 
   if (length < 2 || data[0] != 0x9a)
     return;

esphome/components/lightwaverf/lightwaverf.cpp

@@ -1,3 +1,4 @@
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 #ifdef USE_ESP8266
@@ -44,13 +45,16 @@ void LightWaveRF::send_rx(const std::vector<uint8_t> &msg, uint8_t repeats, bool
 }
 
 void LightWaveRF::print_msg_(uint8_t *msg, uint8_t len) {
-  char buffer[65];
+#if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_DEBUG
+  char buffer[65];  // max 10 entries * 6 chars + null
   ESP_LOGD(TAG, " Received code (len:%i): ", len);
 
+  size_t pos = 0;
   for (int i = 0; i < len; i++) {
-    sprintf(&buffer[i * 6], "0x%02x, ", msg[i]);
+    pos = buf_append_printf(buffer, sizeof(buffer), pos, "0x%02x, ", msg[i]);
   }
   ESP_LOGD(TAG, "[%s]", buffer);
+#endif
 }
 
 void LightWaveRF::dump_config() {

esphome/components/rf_bridge/rf_bridge.cpp

@@ -1,6 +1,7 @@
 #include "rf_bridge.h"
-#include "esphome/core/log.h"
 #include "esphome/core/application.h"
+#include "esphome/core/helpers.h"
+#include "esphome/core/log.h"
 #include <cinttypes>
 #include <cstring>
 
@@ -72,9 +73,9 @@ bool RFBridgeComponent::parse_bridge_byte_(uint8_t byte) {
 
       data.length = raw[2];
       data.protocol = raw[3];
-      char next_byte[3];
+      char next_byte[3];  // 2 hex chars + null
       for (uint8_t i = 0; i < data.length - 1; i++) {
-        sprintf(next_byte, "%02X", raw[4 + i]);
+        buf_append_printf(next_byte, sizeof(next_byte), 0, "%02X", raw[4 + i]);
         data.code += next_byte;
       }
 
@@ -90,10 +91,10 @@ bool RFBridgeComponent::parse_bridge_byte_(uint8_t byte) {
 
       uint8_t buckets = raw[2] << 1;
       std::string str;
-      char next_byte[3];
+      char next_byte[3];  // 2 hex chars + null
 
       for (uint32_t i = 0; i <= at; i++) {
-        sprintf(next_byte, "%02X", raw[i]);
+        buf_append_printf(next_byte, sizeof(next_byte), 0, "%02X", raw[i]);
         str += next_byte;
         if ((i > 3) && buckets) {
           buckets--;

esphome/components/spi_led_strip/spi_led_strip.cpp

@@ -1,4 +1,5 @@
 #include "spi_led_strip.h"
+#include "esphome/core/helpers.h"
 
 namespace esphome {
 namespace spi_led_strip {
@@ -47,15 +48,14 @@ void SpiLedStrip::dump_config() {
 void SpiLedStrip::write_state(light::LightState *state) {
   if (this->is_failed())
     return;
-  if (ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE) {
-    char strbuf[49];
-    size_t len = std::min(this->buffer_size_, (size_t) (sizeof(strbuf) - 1) / 3);
-    memset(strbuf, 0, sizeof(strbuf));
-    for (size_t i = 0; i != len; i++) {
-      sprintf(strbuf + i * 3, "%02X ", this->buf_[i]);
-    }
+#if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE
+  {
+    char strbuf[49];  // format_hex_pretty_size(16) = 48, fits 16 bytes
+    size_t len = std::min(this->buffer_size_, (size_t) 16);
+    format_hex_pretty_to(strbuf, sizeof(strbuf), this->buf_, len, ' ');
     esph_log_v(TAG, "write_state: buf = %s", strbuf);
   }
+#endif
   this->enable();
   this->write_array(this->buf_, this->buffer_size_);
   this->disable();