From: Tomas Mraz <tomas@openssl.org>
Date: Wed, 18 Jan 2023 08:27:53 +0000 (+0100)
Subject: pk7_doit.c: Check return of BIO_set_md() calls
X-Git-Tag: openssl-3.2.0-alpha1~1327
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6eebe6c0238178356114a96a7858f36b24172847;p=thirdparty%2Fopenssl.git

pk7_doit.c: Check return of BIO_set_md() calls

These calls invoke EVP_DigestInit() which can fail for digests
with implicit fetches. Subsequent EVP_DigestUpdate() from BIO_write()
or EVP_DigestFinal() from BIO_read() will segfault on NULL
dereference. This can be triggered by an attacker providing
PKCS7 data digested with MD4 for example if the legacy provider
is not loaded.

If BIO_set_md() fails the md BIO cannot be used.

CVE-2023-0401

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
---

diff --git a/crypto/pkcs7/pk7_doit.c b/crypto/pkcs7/pk7_doit.c
index 148cbc4f9d4..e39821a205d 100644
--- a/crypto/pkcs7/pk7_doit.c
+++ b/crypto/pkcs7/pk7_doit.c
@@ -84,7 +84,11 @@ static int pkcs7_bio_add_digest(BIO **pbio, X509_ALGOR *alg,
     }
     (void)ERR_pop_to_mark();
 
-    BIO_set_md(btmp, md);
+    if (BIO_set_md(btmp, md) <= 0) {
+        ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
+        EVP_MD_free(fetched);
+        goto err;
+    }
     EVP_MD_free(fetched);
     if (*pbio == NULL)
         *pbio = btmp;
@@ -523,7 +527,11 @@ BIO *PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert)
             }
             (void)ERR_pop_to_mark();
 
-            BIO_set_md(btmp, md);
+            if (BIO_set_md(btmp, md) <= 0) {
+                EVP_MD_free(evp_md);
+                ERR_raise(ERR_LIB_PKCS7, ERR_R_BIO_LIB);
+                goto err;
+            }
             EVP_MD_free(evp_md);
             if (out == NULL)
                 out = btmp;