Changelog entry for the union initialization fixes
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/union-initialization.txt b/ChangeLog.d/union-initialization.txt
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+Bugfix
+ * Fix failures of PSA multipart or interruptible operations when the
+ library or the application is built with a compiler where
+ "union foo x = {0}" does not initialize non-default members of the
+ union, such as GCC 15 and some versions of Clang 18. This affected MAC
+ multipart operations, MAC-based key derivation operations, interruptible
+ signature, interruptible verification, and potentially other operations
+ when using third-party drivers. This also affected one-shot MAC
+ operations using the built-in implementation. Fixes #9814.
+ * On entry to PSA driver entry points that set up a multipart operation
+ ("xxx_setup"), the operation object is supposed to be all-bits-zero.
+ This was sometimes not the case when an operation object is reused,
+ or with compilers where "union foo x = {0}" does not initialize
+ non-default members of the union. The PSA core now ensures that this
+ guarantee is met in all cases. Fixes #9975.