Test for out-of-bounds write when requesting zero bytes from shake

Signed-off-by: Patrick Steuer <patrick.steuer@de.ibm.com>

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9433)

1 files changed, 22 insertions, 0 deletions

diff --git a/test/evp_test.c b/test/evp_test.c
index 029738f296..76a0231c8b 100644
--- a/test/evp_test.c
+++ b/test/evp_test.c
@@ -407,6 +407,28 @@ static int digest_test_run(EVP_TEST *t)
     }
 
     if (EVP_MD_flags(expected->digest) & EVP_MD_FLAG_XOF) {
+        EVP_MD_CTX *mctx_cpy;
+        char dont[] = "touch";
+
+        if (!TEST_ptr(mctx_cpy = EVP_MD_CTX_new())) {
+            goto err;
+        }
+        if (!EVP_MD_CTX_copy(mctx_cpy, mctx)) {
+            EVP_MD_CTX_free(mctx_cpy);
+            goto err;
+        }
+        if (!EVP_DigestFinalXOF(mctx_cpy, (unsigned char *)dont, 0)) {
+            EVP_MD_CTX_free(mctx_cpy);
+            t->err = "DIGESTFINALXOF_ERROR";
+            goto err;
+        }
+        if (!TEST_str_eq(dont, "touch")) {
+            EVP_MD_CTX_free(mctx_cpy);
+            t->err = "DIGESTFINALXOF_ERROR";
+            goto err;
+        }
+        EVP_MD_CTX_free(mctx_cpy);
+
         got_len = expected->output_len;
         if (!EVP_DigestFinalXOF(mctx, got, got_len)) {
             t->err = "DIGESTFINALXOF_ERROR";