Make entropy double-free work
Although the library documentation does not guarantee that calling
mbedtls_entropy_free() twice works, it's a plausible assumption and it's
natural to write code that frees an object twice. While this is uncommon for
an entropy context, which is usually a global variable, it came up in our
own unit tests (random_twice tests in test_suite_random in the
development branch).
Announce this in the same changelog entry as for RSA because it's the same
bug in the two modules.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/include/mbedtls/entropy.h b/include/mbedtls/entropy.h
index 1e1d3f5..1d6e9b8 100644
--- a/include/mbedtls/entropy.h
+++ b/include/mbedtls/entropy.h
@@ -147,13 +147,15 @@
*/
typedef struct mbedtls_entropy_context
{
- int accumulator_started;
+ int accumulator_started; /* 0 after init.
+ * 1 after the first update.
+ * -1 after free. */
#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
mbedtls_sha512_context accumulator;
#else
mbedtls_sha256_context accumulator;
#endif
- int source_count;
+ int source_count; /* Number of entries used in source. */
mbedtls_entropy_source_state source[MBEDTLS_ENTROPY_MAX_SOURCES];
#if defined(MBEDTLS_HAVEGE_C)
mbedtls_havege_state havege_data;