Fix EVP_DigestInit_ex with NULL digest

Calling EVP_DigestInit_ex which has already had the digest set up for it
should be possible. You are supposed to be able to pass NULL for the type.
However currently this seg faults.

Reviewed-by: Andy Polyakov <appro@openssl.org>
(cherry picked from commit a01087027bd0c5ec053d4eabd972bd942bfcd92f)

diff --git a/crypto/evp/digest.c b/crypto/evp/digest.c
index 386a3f73bc914bb2d6fd882413c9a25ed62c0b0d..2e202c8fe031a63b8292057e1cc6fb25a184063f 100644 (file)
--- a/crypto/evp/digest.c
+++ b/crypto/evp/digest.c
@@ -191,9 +191,12 @@ int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl)
             ctx->engine = impl;
         } else
             ctx->engine = NULL;
-    } else if (!ctx->digest) {
-        EVPerr(EVP_F_EVP_DIGESTINIT_EX, EVP_R_NO_DIGEST_SET);
-        return 0;
+    } else {
+        if (!ctx->digest) {
+            EVPerr(EVP_F_EVP_DIGESTINIT_EX, EVP_R_NO_DIGEST_SET);
+            return 0;
+        }
+        type = ctx->digest;
     }
 #endif
     if (ctx->digest != type) {