Fix NULL+0 in addition 0 + 0
Fix undefined behavior (typically harmless in practice) of
mbedtls_mpi_add_mpi(), mbedtls_mpi_add_abs() and mbedtls_mpi_add_int() when
both operands are 0 and the left operand is represented with 0 limbs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/mpi-add-0-ub.txt b/ChangeLog.d/mpi-add-0-ub.txt
new file mode 100644
index 0000000..9f131a4
--- /dev/null
+++ b/ChangeLog.d/mpi-add-0-ub.txt
@@ -0,0 +1,4 @@
+Bugfix
+ * Fix undefined behavior (typically harmless in practice) of
+ mbedtls_mpi_add_mpi(), mbedtls_mpi_add_abs() and mbedtls_mpi_add_int()
+ when both operands are 0 and the left operand is represented with 0 limbs.