From: Jiasheng Jiang <jiasheng@purdue.edu>
Date: Fri, 22 Mar 2024 22:12:50 +0000 (+0000)
Subject: signature/dsa_sig.c: Add checks for the EVP_MD_get_size()
X-Git-Tag: openssl-3.4.0-alpha1~725
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f4174b6db41650363e41af42e82de9cc7ef09a5e;p=thirdparty%2Fopenssl.git

signature/dsa_sig.c: Add checks for the EVP_MD_get_size()

Add checks for the EVP_MD_get_size() to avoid integer overflow and then explicitly cast from int to size_t.

Fixes: 45a845e40b ("Add EVP_DigestSign/EVP_DigestVerify support for DSA")
Signed-off-by: Jiasheng Jiang <jiasheng@purdue.edu>

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/23948)
---

diff --git a/providers/implementations/signature/dsa_sig.c b/providers/implementations/signature/dsa_sig.c
index b89a0f6836b..12cbdb4356d 100644
--- a/providers/implementations/signature/dsa_sig.c
+++ b/providers/implementations/signature/dsa_sig.c
@@ -93,8 +93,14 @@ typedef struct {
 
 static size_t dsa_get_md_size(const PROV_DSA_CTX *pdsactx)
 {
-    if (pdsactx->md != NULL)
-        return EVP_MD_get_size(pdsactx->md);
+    int md_size;
+
+    if (pdsactx->md != NULL) {
+        md_size = EVP_MD_get_size(pdsactx->md);
+        if (md_size <= 0)
+            return 0;
+        return (size_t)md_size;
+    }
     return 0;
 }