From 481379f14d43fc234a5fee7d95932c50e93a9690 Mon Sep 17 00:00:00 2001
From: Felipe Neves <felipe.neves@espressif.com>
Date: Tue, 17 Mar 2020 15:58:25 -0300
Subject: [PATCH] multi_heap:  ensure that malloc(0) return NULL pointer in any
 poisoning configuration

---
 components/heap/multi_heap_poisoning.c         | 9 +++++++++
 components/heap/test/test_aligned_alloc_caps.c | 9 ++++++++-
 components/heap/test/test_malloc.c             | 7 +++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/components/heap/multi_heap_poisoning.c b/components/heap/multi_heap_poisoning.c
index 119017d00..ec620c079 100644
--- a/components/heap/multi_heap_poisoning.c
+++ b/components/heap/multi_heap_poisoning.c
@@ -187,6 +187,10 @@ static bool verify_fill_pattern(void *data, size_t size, bool print_errors, bool
 
 void *multi_heap_aligned_alloc(multi_heap_handle_t heap, size_t size, size_t alignment)
 {
+    if (!size) {
+        return NULL;
+    }
+
     if (size > SIZE_MAX  - POISON_OVERHEAD) {
         return NULL;
     }
@@ -213,9 +217,14 @@ void *multi_heap_aligned_alloc(multi_heap_handle_t heap, size_t size, size_t ali
 
 void *multi_heap_malloc(multi_heap_handle_t heap, size_t size)
 {
+    if (!size) {
+        return NULL;
+    }
+    
     if(size > SIZE_MAX - POISON_OVERHEAD) {
         return NULL;
     }
+
     multi_heap_internal_lock(heap);
     poison_head_t *head = multi_heap_malloc_impl(heap, size + POISON_OVERHEAD);
     uint8_t *data = NULL;
diff --git a/components/heap/test/test_aligned_alloc_caps.c b/components/heap/test/test_aligned_alloc_caps.c
index 845d7cf44..67226b29a 100644
--- a/components/heap/test/test_aligned_alloc_caps.c
+++ b/components/heap/test/test_aligned_alloc_caps.c
@@ -159,4 +159,11 @@ TEST_CASE("Capabilities aligned calloc test", "[heap]")
     } 
 #endif
 
-}
\ No newline at end of file
+}
+
+TEST_CASE("aligned_alloc(0) should return a NULL pointer", "[heap]")
+{
+    void *p;
+    p = heap_caps_aligned_alloc(32, 0, MALLOC_CAP_DEFAULT);
+    TEST_ASSERT(p == NULL);
+}
diff --git a/components/heap/test/test_malloc.c b/components/heap/test/test_malloc.c
index cfc634bad..11bb3d9c9 100644
--- a/components/heap/test/test_malloc.c
+++ b/components/heap/test/test_malloc.c
@@ -127,3 +127,10 @@ 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);
+}
+