ESYS: Remove unnecessary size check in StartAuthSession

The check whether the secret size is zero can be removed because  size zero is
possible if no tpmKey for encryption is used and the authValue of the bind
object has length 0.

Signed-off-by: Juergen Repp <Juergen.Repp@sit.fraunhofer.de>

1 files changed, 5 insertions, 5 deletions

diff --git a/src/tss2-esys/api/Esys_StartAuthSession.c b/src/tss2-esys/api/Esys_StartAuthSession.c
index 6ea60c41..0ea2829a 100644
--- a/src/tss2-esys/api/Esys_StartAuthSession.c
+++ b/src/tss2-esys/api/Esys_StartAuthSession.c
@@ -450,11 +450,11 @@ Esys_StartAuthSession_Finish(
             secret_size += keyHash_size;
         if (bind != ESYS_TR_NONE && bindNode != NULL)
             secret_size += bindNode->auth.size;
-        if (secret_size == 0) {
-            return_error(TSS2_ESYS_RC_GENERAL_FAILURE,
-                         "Invalid secret size (0).");
-        }
-        uint8_t *secret = malloc(secret_size);
+        /* 
+         * A non null pointer for secret is required by the subsequent functions,
+         * hence a malloc is called with size 1 if secret_size is zero.
+         */
+        uint8_t *secret = malloc(secret_size ? secret_size : 1);
         if (secret == NULL) {
             LOG_ERROR("Out of memory.");
             return TSS2_ESYS_RC_MEMORY;