Fixed heap overflow caused by vector_resize

.gitignore

@@ -53,3 +53,6 @@ dkms.conf
 
 # debug information files
 *.dwo
+
+# Visual Studio Code
+.vscode/

Makefile

@@ -1,7 +1,7 @@
 CC = gcc
 CFLAGS = -Wall -Wextra -Werror -pedantic-errors -fstack-protector-strong \
 	-fsanitize=address -fsanitize=undefined -fstack-clash-protection \
-	-Wwrite-strings -std=c99
+	-Wwrite-strings -g -std=c99
 
 SRC_DIR = src
 OBJ_DIR = obj

src/vector.c

@@ -70,18 +70,18 @@ vector_result_t vector_new(size_t size, size_t data_size) {
 vector_result_t vector_resize(vector_t *vector) {
     vector_result_t result = {0};
 
-    size_t old_capacity = vector->capacity;
-    vector->capacity = (old_capacity > 0 ? ((old_capacity * 3) / 2) : 1);
+    const size_t old_capacity = vector->capacity;
+    const size_t new_capacity = old_capacity > 0 ? old_capacity * 2 : 1;
 
     // Check for stack overflow errors
-    if (vector->capacity > SIZE_MAX / vector->data_size) {
+    if (new_capacity > SIZE_MAX / vector->data_size) {
         result.status = VECTOR_ERR_OVERFLOW;
         SET_MSG(result, "Exceeded maximum size while resizing vector");
 
         return result;
     }
 
-    void *new_elements = realloc(vector->elements, (vector->capacity * vector->data_size));
+    void *new_elements = realloc(vector->elements, new_capacity * vector->data_size);
     if (new_elements == NULL) {
         result.status = VECTOR_ERR_ALLOCATE;
         SET_MSG(result, "Failed to reallocate memory for vector");
@@ -90,6 +90,7 @@ vector_result_t vector_resize(vector_t *vector) {
     }
 
     vector->elements = new_elements;
+    vector->capacity = new_capacity;
 
     result.status = VECTOR_OK;
     SET_MSG(result, "Vector successfully resized");
@@ -184,7 +185,7 @@ vector_result_t vector_push(vector_t *vector, void *value) {
     }
 
     // Check whether vector has enough space available
-    if (vector->capacity == vector->size) {
+    if (vector->size == vector->capacity) {
         result = vector_resize(vector);
         if (result.status != VECTOR_OK) {
             return result;

tests/test_vector.c

@@ -55,7 +55,7 @@ void test_vector_push() {
 
 // Trigger vector reallocation
 void test_vector_push_realloc() {
-    vector_result_t res = vector_new(2, sizeof(int));
+    vector_result_t res = vector_new(1, sizeof(int));
 
     assert(res.status == VECTOR_OK);
     vector_t *v = res.value.vector;
@@ -66,7 +66,7 @@ void test_vector_push_realloc() {
     }
 
     assert(vector_size(v) == 5);
-    assert(vector_capacity(v) >= 5);
+    assert(vector_capacity(v) > 5);
 
     vector_destroy(v);
 }

usage.c

@@ -54,8 +54,8 @@ vector_order_t cmp_int_desc(const void *x, const void *y) {
 }
 
 int vector_usage() {
-    // Create a vector of 5 integers
-    vector_result_t res = vector_new(5, sizeof(int));
+    // Create a vector of 3 integers
+    vector_result_t res = vector_new(3, sizeof(int));
     if (res.status != VECTOR_OK) {
         printf("Error while creating vector: %s\n", res.message);
 
@@ -64,8 +64,8 @@ int vector_usage() {
 
     vector_t *vector = res.value.vector;
 
-    // Push some values
-    for (int idx = 0; idx <= 5; idx++) {
+    // Push some values to trigger reallocation
+    for (int idx = 0; idx < 5; idx++) {
         vector_result_t add_res = vector_push(vector, &idx);
         if (add_res.status != VECTOR_OK) {
             printf("Error while adding elements: %s\n", add_res.message);
@@ -76,7 +76,7 @@ int vector_usage() {
 
     // Print vector size and capacity
     printf("Vector size (should be 5): %zu\n", vector_size(vector));
-    printf("Vector capacity (should be >= 5): %zu\n\n", vector_capacity(vector));
+    printf("Vector capacity (should be > 5): %zu\n\n", vector_capacity(vector));
 
     // Print the whole vector
     for (size_t idx = 0; idx < vector_size(vector); idx++) {