Reword ChangeLog entry for shared memory work
Specifically:
* Clarify that passing shared buffers is now secure by default (not
newly supported)
* Remove spurious hyphen
* Clarify that we do not guarantee copying, but rather guarantee
protection, allowing us to implement this differently in future if
required.
* Mention both protection of inputs from modification and outputs from
exposure of intermediate results.
* Invert the config option, from an enable-option to a disable-option.
Signed-off-by: David Horstmann <david.horstmann@arm.com>
diff --git a/ChangeLog.d/psa-shared-memory-protection.txt b/ChangeLog.d/psa-shared-memory-protection.txt
index f4f6ea0..6322563 100644
--- a/ChangeLog.d/psa-shared-memory-protection.txt
+++ b/ChangeLog.d/psa-shared-memory-protection.txt
@@ -1,8 +1,10 @@
Security
- * Support calling PSA functions with buffer arguments that are in memory
- shared with an untrusted party. The PSA core now makes copies of all
- buffers before passing them to drivers to protect drivers against
- modification of buffers during operations.
- This feature increases code-size and memory usage. If buffers passed to
- PSA functions are all trusted, buffer copying may be disabled by
- unsetting MBEDTLS_PSA_COPY_CALLER_BUFFERS.
+ * Passing buffers that are stored in untrusted memory as arguments
+ to PSA functions is now secure by default.
+ The PSA core now protects against modification of inputs or exposure
+ of intermediate outputs during operations. This is currently implemented
+ by copying buffers.
+ This feature increases code size and memory usage. If buffers passed to
+ PSA functions are owned exclusively by the PSA core for the duration of
+ the function call, copying may be disabled by setting
+ MBEDTLS_PSA_ASSUME_EXCLUSIVE_BUFFERS.