diff --git a/src/mbedtls_pkcs7.c b/src/mbedtls_pkcs7.c
index 90895c6cd9b7adae1a894efed470304ffdce3d0c..ac98de6c71721ac1998e990775fd0f78a51e92fc 100755
--- a/src/mbedtls_pkcs7.c
+++ b/src/mbedtls_pkcs7.c
@@ -400,7 +400,7 @@ static int ParseSignedDataSignerInfos(unsigned char **p, const unsigned char *en
         PKCS7_ERR_RETURN_WITH_LOG(rc);
 
         if (*p < end) {
-            signers->next = Pkcs7Calloc(1, sizeof(*signers));
+            signers->next = Pkcs7Calloc(1, sizeof(SignerInfo));
             if (signers->next == NULL) {
                 /* release resource in main entry. */
                 return PKCS7_MEMORY_EXHAUST;
@@ -516,7 +516,7 @@ static int ParseSignedDataCerts(unsigned char **p, const unsigned char *end, mbe
         LOG_ERROR("Has no certificates in signed data.");
         return PKCS7_SUCC;
     }
-    *certs = mbedtls_calloc(1, sizeof(**certs));
+    *certs = mbedtls_calloc(1, sizeof(mbedtls_x509_crt));
     if (*certs == NULL) {
         return PKCS7_MEMORY_EXHAUST;
     }
@@ -1106,7 +1106,7 @@ SignersResovedInfo *PKCS7_GetAllSignersResolvedInfo(const Pkcs7 *pkcs7)
     if (signersCnt == 0) {
         return NULL;
     }
-    sri = Pkcs7Calloc(1, sizeof(*sri));
+    sri = Pkcs7Calloc(1, sizeof(SignersResovedInfo));
     if (sri == NULL) {
         return NULL;
     }