the new function chunk_free_randomized() overwrites the contents of a chunk with pseudo-random bytes before freeing it

2 files changed, 27 insertions, 0 deletions

diff --git a/src/libstrongswan/chunk.c b/src/libstrongswan/chunk.c
index d70e1723f..9134b5af9 100644
--- a/src/libstrongswan/chunk.c
+++ b/src/libstrongswan/chunk.c
@@ -28,6 +28,7 @@
 
 #include <debug.h>
 #include <printf_hook.h>
+#include <utils/randomizer.h>
 
 /**
  * Empty chunk.
@@ -260,6 +261,27 @@ void chunk_free(chunk_t *chunk)
 /**
  * Described in header.
  */
+void chunk_free_randomized(chunk_t *chunk)
+{
+	if (chunk->ptr)
+	{
+		if (chunk->len > 0)
+		{
+			randomizer_t *randomizer = randomizer_create();
+
+			randomizer->get_pseudo_random_bytes(randomizer,
+												chunk->len, chunk->ptr);
+			randomizer->destroy(randomizer);
+		};
+		free(chunk->ptr);
+		chunk->ptr = NULL;
+	}
+	chunk->len = 0;
+}
+
+/**
+ * Described in header.
+ */
 chunk_t chunk_skip(chunk_t chunk, size_t bytes)
 {
 	if (chunk.len > bytes)
diff --git a/src/libstrongswan/chunk.h b/src/libstrongswan/chunk.h
index a13ccfc22..70dc2ce44 100644
--- a/src/libstrongswan/chunk.h
+++ b/src/libstrongswan/chunk.h
@@ -89,6 +89,11 @@ bool chunk_write(chunk_t chunk, const char *path, const char *label, mode_t mask
 void chunk_free(chunk_t *chunk);
 
 /**
+ * Overwrite the contents of a chunk with pseudo-random bytes and free them
+ */
+void chunk_free_randomized(chunk_t *chunk);
+
+/**
  * Initialize a chunk to point to buffer inspectable by sizeof()
  */
 #define chunk_from_buf(str) { str, sizeof(str) }