Fix missing state check for tls12_prf output
Fix PSA_ALG_TLS12_PRF and PSA_ALG_TLS12_PSK_TO_MS being too permissive
about missing inputs.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/ChangeLog.d/psa_key_derivation-bad_workflow.txt b/ChangeLog.d/psa_key_derivation-bad_workflow.txt
new file mode 100644
index 0000000..7fd03e6
--- /dev/null
+++ b/ChangeLog.d/psa_key_derivation-bad_workflow.txt
@@ -0,0 +1,3 @@
+Bugfix
+ * Fix PSA_ALG_TLS12_PRF and PSA_ALG_TLS12_PSK_TO_MS being too permissive
+ about missing inputs.
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index db44e3f..d8a5d82 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -3731,6 +3731,17 @@
psa_status_t status;
uint8_t offset, length;
+ switch( tls12_prf->state )
+ {
+ case PSA_TLS12_PRF_STATE_LABEL_SET:
+ tls12_prf->state = PSA_TLS12_PRF_STATE_OUTPUT;
+ break;
+ case PSA_TLS12_PRF_STATE_OUTPUT:
+ break;
+ default:
+ return( PSA_ERROR_BAD_STATE );
+ }
+
while( output_length != 0 )
{
/* Check if we have fully processed the current block. */