Add missing error checking in PKCS7

Check the return value of BIO_set_md(). Prompted by OpenSSL's fix for
CVE-2023-0401 (the crash in that bug is an OpenSSL 3-only problem due
to provider design).

ok beck jsing

diff --git a/lib/libcrypto/pkcs7/pk7_doit.c b/lib/libcrypto/pkcs7/pk7_doit.c
index 1fcc37a..d5edaed 100644 (file)
--- a/lib/libcrypto/pkcs7/pk7_doit.c
+++ b/lib/libcrypto/pkcs7/pk7_doit.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pk7_doit.c,v 1.51 2023/02/16 08:38:17 tb Exp $ */
+/* $OpenBSD: pk7_doit.c,v 1.52 2023/03/09 18:20:10 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -112,6 +112,7 @@ PKCS7_bio_add_digest(BIO **pbio, X509_ALGOR *alg)
 {
        BIO *btmp;
        const EVP_MD *md;
+
        if ((btmp = BIO_new(BIO_f_md())) == NULL) {
                PKCS7error(ERR_R_BIO_LIB);
                goto err;
@@ -123,7 +124,11 @@ PKCS7_bio_add_digest(BIO **pbio, X509_ALGOR *alg)
                goto err;
        }
 
-       BIO_set_md(btmp, md);
+       if (BIO_set_md(btmp, md) <= 0) {
+               PKCS7error(ERR_R_BIO_LIB);
+               goto err;
+       }
+
        if (*pbio == NULL)
                *pbio = btmp;
        else if (!BIO_push(*pbio, btmp)) {
@@ -497,7 +502,10 @@ PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert)
                                goto err;
                        }
 
-                       BIO_set_md(btmp, evp_md);
+                       if (BIO_set_md(btmp, evp_md) <= 0) {
+                               PKCS7error(ERR_R_BIO_LIB);
+                               goto err;
+                       }
                        if (out == NULL)
                                out = btmp;
                        else