Zeroising of plaintext buffers to erase unused application data from memory
Signed-off-by: gabor-mezei-arm <gabor.mezei@arm.com>
diff --git a/ChangeLog.d/zeroising_of_plaintext_buffer.txt b/ChangeLog.d/zeroising_of_plaintext_buffer.txt
new file mode 100644
index 0000000..d7dee29
--- /dev/null
+++ b/ChangeLog.d/zeroising_of_plaintext_buffer.txt
@@ -0,0 +1,4 @@
+Security
+ * Zeroising of plaintext buffers in mbedtls_ssl_read() to erase unused
+ application data from memory. Reported in #689 by
+ Johan Uppman Bruce of Sectra.
\ No newline at end of file
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index d32afac..be17336 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -5581,6 +5581,10 @@
memcpy( buf, ssl->in_offt, n );
ssl->in_msglen -= n;
+ /* Zeroising the plaintext buffer to erase unused application data
+ from the memory. */
+ mbedtls_platform_zeroize( ssl->in_offt, n );
+
if( ssl->in_msglen == 0 )
{
/* all bytes consumed */
