From 4a9160a72c989fef86ee1b4ad8b818f4201dfbbe Mon Sep 17 00:00:00 2001
From: Felipe Neves <felipe.neves@espressif.com>
Date: Fri, 27 Mar 2020 14:39:23 -0300
Subject: [PATCH] multi_heap: ensure that malloc(0) return NULL pointer in any
 poisoning configuration

---
 components/heap/multi_heap_poisoning.c | 4 ++++
 components/heap/test/test_malloc.c     | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/components/heap/multi_heap_poisoning.c b/components/heap/multi_heap_poisoning.c
index a896043ab..ae4cfd44d 100644
--- a/components/heap/multi_heap_poisoning.c
+++ b/components/heap/multi_heap_poisoning.c
@@ -184,6 +184,10 @@ static bool verify_fill_pattern(void *data, size_t size, bool print_errors, bool
 
 void *multi_heap_malloc(multi_heap_handle_t heap, size_t size)
 {
+    if (!size) {
+        return NULL;
+    }
+
     if(size > SIZE_MAX - POISON_OVERHEAD) {
         return NULL;
     }
diff --git a/components/heap/test/test_malloc.c b/components/heap/test/test_malloc.c
index 703270c9a..74182ec13 100644
--- a/components/heap/test/test_malloc.c
+++ b/components/heap/test/test_malloc.c
@@ -132,3 +132,9 @@ TEST_CASE("unreasonable allocs should all fail", "[heap]")
     TEST_ASSERT_NULL(test_malloc_wrapper(xPortGetFreeHeapSize() - 1));
 }
 
+TEST_CASE("malloc(0) should return a NULL pointer", "[heap]")
+{
+    void *p;
+    p = malloc(0);
+    TEST_ASSERT(p == NULL);
+}