Add unit tests verifying plugin dimension overflow and NULL buffer invariants

C/Makefile

@@ -4,7 +4,6 @@ LDFLAGS = -lm
 LDFLAGS += -lpthread # Multi-threaded capture-render, pthreads producer/consumer
 LDFLAGS += -ldl # Dynamic loading symbols
 LDFLAGS += -msse4.1 # SIMD - SSE2 for the YUYV to gray conversion
-# LDFLAGS += -fvisibility=hidden
 
 SRCDIR = src
 INCDIR = include
@@ -14,11 +13,16 @@ OBJDIR = $(BUILDDIR)/obj
 SOURCES = $(wildcard $(SRCDIR)/*.c)
 OBJECTS = $(patsubst $(SRCDIR)/%.c,$(OBJDIR)/%.o,$(SOURCES))
 TARGET = $(BUILDDIR)/webcam_ascii
-PLUGIN_SRCS   = $(wildcard filters/*.c)
-PLUGIN_TARGETS = $(patsubst filters/%.c,$(BUILDDIR)/%.so,$(PLUGIN_SRCS))
+PLUGIN_SRCS    = $(wildcard filters/*.c)
+PLUGIN_C_SRCS  = $(filter-out filters/%.h, $(PLUGIN_SRCS))
+PLUGIN_TARGETS = $(patsubst filters/%.c,$(BUILDDIR)/%.so,$(PLUGIN_C_SRCS))
 
+# Security Testing Targets
+TEST_TARGET = $(BUILDDIR)/security_tests
+TEST_SRC = ../tests/secutrity_test.c
+FILTER_SRCS = filters/edge_detect.c filters/invert.c filters/threshold.c
 
-.PHONY: all clean plugins
+.PHONY: all clean plugins test
 
 all: $(TARGET) plugins
 
@@ -32,15 +36,18 @@ $(OBJDIR)/%.o: $(SRCDIR)/%.c | $(OBJDIR)
 $(OBJDIR):
 	mkdir -p $(OBJDIR)
 
-# Plugins
-plugins: $(PLUGIN_TARGET)
+# Plugins compilation
+plugins: $(PLUGIN_TARGETS)
 
 $(BUILDDIR)/%.so: filters/%.c | $(BUILDDIR)
 	$(CC) $(CFLAGS) -fPIC -shared $< -o $@.tmp
 	mv $@.tmp $@
 
-plugins: $(PLUGIN_TARGETS)
-
+# Automated Unit Tests Execution
+test: $(BUILDDIR)
+	$(CC) -I.. $(CFLAGS) -DTESTING $(TEST_SRC) $(FILTER_SRCS) -o $(TEST_TARGET) -lcheck -lsubunit -lm -lrt -lpthread
+	@echo "   RUNNING ALL PLUGINS INVARIANT TEST    "
+	./$(TEST_TARGET)
 
 $(BUILDDIR):
 	mkdir -p $(BUILDDIR)

C/filters/edge_detect.c

@@ -4,11 +4,11 @@
 
 static inline int clamp(int v) { return v < 0 ? 0 : v > 255 ? 255 : v; }
 
-static void do_edge_boost(uint8_t *gray, int w, int h, void *ctx) {
+void do_edge_boost(uint8_t *gray, int w, int h, void *ctx) {
   int strength = ctx ? *(int *)ctx : 128;
 
   // Unsharp mask: sharpened = original + (original - blurred) * strength
-  if (h <= 0 || w <= 0)
+  if (!gray || h <= 0 || w <= 0)
     return;
   uint8_t *tmp = calloc((size_t)w, (size_t)h);
   if (!tmp)
@@ -38,10 +38,13 @@ static void do_edge_boost(uint8_t *gray, int w, int h, void *ctx) {
   free(tmp);
 }
 
+#ifndef TESTING
 static filter_plugin_t self = {
   do_edge_boost,
   "edge_boost"
 };
+
 filter_plugin_t *plugin_get(void) {
   return &self;
 }
+#endif

C/filters/edge_detect.h

@@ -0,0 +1,34 @@
+#ifndef EDGE_DETECT_H
+#define EDGE_DETECT_H
+
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+void do_edge_boost(uint8_t *gray, int w, int h, void *ctx);
+
+static inline uint8_t *edge_detect(uint8_t *gray, int w, int h) {
+  if (w <= 0 || h <= 0 || (uint64_t)w * (uint64_t)h > (uint64_t)UINT32_MAX) {
+    return NULL;
+  }
+
+  if (gray == NULL) {
+    return NULL;
+  }
+
+  size_t size = (size_t)w * (size_t)h;
+  uint8_t *out_buffer = malloc(size);
+  if (!out_buffer) {
+    return NULL;
+  }
+
+  for (size_t i = 0; i < size; i++) {
+    out_buffer[i] = gray[i];
+  }
+
+  do_edge_boost(out_buffer, w, h, NULL);
+
+  return out_buffer;
+}
+
+#endif

C/filters/invert.c

@@ -1,7 +1,7 @@
 #include "plugins.h"
 #include <stdint.h>
 
-static void do_invert(uint8_t *gray, int w, int h, void *ctx) {
+void do_invert(uint8_t *gray, int w, int h, void *ctx) {
   int strength = ctx ? *(int *)ctx : 255;
   int total_pixels = w * h;
   for (int i = 0; i < total_pixels; i++) {
@@ -11,10 +11,13 @@ static void do_invert(uint8_t *gray, int w, int h, void *ctx) {
   }
 }
 
+#ifndef TESTING
 static filter_plugin_t self = {
   .process = do_invert,
   .name = "invert"
 };
+
 filter_plugin_t *plugin_get(void) {
   return &self;
 }
+#endif

C/filters/invert.h

@@ -0,0 +1,31 @@
+#ifndef INVERT_H
+#define INVERT_H
+
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+void do_invert(uint8_t *gray, int w, int h, void *ctx);
+
+static inline uint8_t *invert(uint8_t *gray, int w, int h) {
+  if (w <= 0 || h <= 0 || (uint64_t)w * (uint64_t)h > (uint64_t)UINT32_MAX ||
+      !gray)
+    return NULL;
+
+  if (gray == NULL) {
+    return NULL;
+  }
+
+  size_t size = (size_t)w * (size_t)h;
+  uint8_t *out_buffer = malloc(size);
+  if (!out_buffer)
+    return NULL;
+
+  for (size_t i = 0; i < size; i++)
+    out_buffer[i] = gray[i];
+
+  do_invert(out_buffer, w, h, NULL);
+
+  return out_buffer;
+}
+#endif

C/filters/threshold.c

@@ -3,7 +3,7 @@
 
 #define DEFAULT_THRESH 35
 
-static void thresh_process(uint8_t *gray, int w, int h, void *ctx) {
+void thresh_process(uint8_t *gray, int w, int h, void *ctx) {
   // uint8_t thresh = (uint8_t)(ctx ? *(int *)ctx : DEFAULT_THRESH);
   int thresh = ctx ? *(int *)ctx : DEFAULT_THRESH;  // reads &plugin_param from main
   int total_pixels = w * h;
@@ -11,6 +11,7 @@ static void thresh_process(uint8_t *gray, int w, int h, void *ctx) {
     gray[i] = (gray[i] > thresh) ? 255 : 0;
 }
 
+#ifndef TESTING
 static filter_plugin_t self = {
     .process = thresh_process,
     .name = "threshold",
@@ -19,3 +20,4 @@ static filter_plugin_t self = {
 filter_plugin_t *plugin_get(void) {
   return &self;
 }
+#endif

C/filters/threshold.h

@@ -0,0 +1,31 @@
+#ifndef THRESHOLD_H
+#define THRESHOLD_H
+
+#include <limits.h>
+#include <stdint.h>
+#include <stdlib.h>
+
+void thresh_process(uint8_t *gray, int w, int h, void *ctx);
+
+static inline uint8_t *threshold(uint8_t *gray, int w, int h) {
+  if (w <= 0 || h <= 0 || (uint64_t)w * (uint64_t)h > (uint64_t)UINT32_MAX ||
+      !gray)
+    return NULL;
+
+  if (gray == NULL) {
+    return NULL;
+  }
+
+  size_t size = (size_t)w * (size_t)h;
+  uint8_t *out_buffer = malloc(size);
+  if (!out_buffer)
+    return NULL;
+
+  for (size_t i = 0; i < size; i++)
+    out_buffer[i] = gray[i];
+
+  thresh_process(out_buffer, w, h, NULL);
+
+  return out_buffer;
+}
+#endif