From bc1841c1b53f33248eb419ff949d469466b4782a Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sun, 13 Sep 2026 17:26:28 -0500
Subject: [PATCH] [esphome] Allocate the OTA noise session and auth buffer
 through RAMAllocator (#19249)

---
 esphome/components/esphome/ota/ota_esphome.cpp       | 9 ++++++++-
 esphome/components/esphome/ota/ota_esphome.h         | 4 ++--
 esphome/components/esphome/ota/ota_esphome_noise.cpp | 6 ++----
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/esphome/components/esphome/ota/ota_esphome.cpp b/esphome/components/esphome/ota/ota_esphome.cpp
index f853ed6a2db..3010df10561 100644
--- a/esphome/components/esphome/ota/ota_esphome.cpp
+++ b/esphome/components/esphome/ota/ota_esphome.cpp
@@ -842,7 +842,14 @@ bool ESPHomeOTAComponent::handle_auth_send_() {
     const size_t hex_size = hasher.get_size() * 2;
     const size_t nonce_len = hasher.get_size() / 4;
     const size_t auth_buf_size = 1 + 3 * hex_size;
-    this->auth_buf_ = std::make_unique<uint8_t[]>(auth_buf_size);
+    // Internal RAM first: 128 of these bytes go straight into the hardware SHA engine
+    this->auth_buf_ =
+        RAMAllocator<uint8_t>(RAMAllocator<uint8_t>::PREFER_INTERNAL).make_unique_array_for_overwrite(auth_buf_size);
+    if (!this->auth_buf_) {
+      this->log_auth_warning_(LOG_STR("No memory"));
+      this->send_error_and_cleanup_(ota::OTA_RESPONSE_ERROR_UNKNOWN);
+      return false;
+    }
     this->auth_buf_pos_ = 0;
 
     char *buf = reinterpret_cast<char *>(this->auth_buf_.get() + 1);
diff --git a/esphome/components/esphome/ota/ota_esphome.h b/esphome/components/esphome/ota/ota_esphome.h
index c6f710b3fcb..68dd0ffb9ef 100644
--- a/esphome/components/esphome/ota/ota_esphome.h
+++ b/esphome/components/esphome/ota/ota_esphome.h
@@ -145,13 +145,13 @@ class ESPHomeOTAComponent final : public ota::OTAComponent {
 
 #ifdef USE_OTA_PASSWORD
   std::string password_;
-  std::unique_ptr<uint8_t[]> auth_buf_;
+  RAMUniquePtr<uint8_t[]> auth_buf_;
 #endif  // USE_OTA_PASSWORD
 #ifdef USE_OTA_ENCRYPTION
 #ifndef USE_OTA_ENCRYPTION_FROM_API
   noise::NoiseContext noise_ctx_;
 #endif
-  std::unique_ptr<NoiseSession> noise_;
+  RAMUniquePtr<NoiseSession> noise_;
 #endif  // USE_OTA_ENCRYPTION
 
   socket::ListenSocket *server_{nullptr};
diff --git a/esphome/components/esphome/ota/ota_esphome_noise.cpp b/esphome/components/esphome/ota/ota_esphome_noise.cpp
index 7401413d6d0..65476572a1e 100644
--- a/esphome/components/esphome/ota/ota_esphome_noise.cpp
+++ b/esphome/components/esphome/ota/ota_esphome_noise.cpp
@@ -7,7 +7,6 @@
 #include "esphome/core/log.h"
 
 #include <cstring>
-#include <new>
 
 #ifdef USE_ESP8266
 #include <pgmspace.h>
@@ -43,9 +42,8 @@ ESPHomeOTAComponent::NoiseSession::~NoiseSession() {
 bool ESPHomeOTAComponent::noise_start_session_(uint8_t server_feature_flags) {
   // A provisioned key cleared between the offer and here is not guarded: the
   // session runs on the zero key load_psk fills in and fails the client's MAC.
-  // Default-init: the frame buffer is written before it is read
-  // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks)
-  this->noise_ = std::unique_ptr<NoiseSession>(new (std::nothrow) NoiseSession);
+  // Default placement, PSRAM first where present: the session only lives for one upload
+  this->noise_ = RAMAllocator<NoiseSession>().make_unique();
   static constexpr size_t PROLOGUE_ACK_LEN = 2;  // OTA_RESPONSE_OK + version
   static constexpr size_t PROLOGUE_CLIENT_FEATURES_LEN = 1;
   static constexpr size_t PROLOGUE_FEATURE_ACK_LEN = 2;  // OTA_RESPONSE_FEATURE_FLAGS + server flags