openssl(1) pkcs7 avoid crash on malformed files

When printing certificates or CRLs, check signed and signedAndEnveloped
before dereferencing them. Prevents crash on inspecting malformed PKCS7
files.

ok jsing

1 files changed, 9 insertions, 5 deletions

diff --git a/src/usr.bin/openssl/pkcs7.c b/src/usr.bin/openssl/pkcs7.c
index 4f0c529424..b0acf3fd98 100644
--- a/src/usr.bin/openssl/pkcs7.c
+++ b/src/usr.bin/openssl/pkcs7.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pkcs7.c,v 1.12 2022/11/11 17:07:39 joshua Exp $ */
+/* $OpenBSD: pkcs7.c,v 1.13 2023/02/08 07:59:24 tb Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -216,12 +216,16 @@ pkcs7_main(int argc, char **argv)
                 i = OBJ_obj2nid(p7->type);
                 switch (i) {
                 case NID_pkcs7_signed:
-                        certs = p7->d.sign->cert;
-                        crls = p7->d.sign->crl;
+                        if (p7->d.sign != NULL) {
+                                certs = p7->d.sign->cert;
+                                crls = p7->d.sign->crl;
+                        }
                         break;
                 case NID_pkcs7_signedAndEnveloped:
-                        certs = p7->d.signed_and_enveloped->cert;
-                        crls = p7->d.signed_and_enveloped->crl;
+                        if (p7->d.signed_and_enveloped != NULL) {
+                                certs = p7->d.signed_and_enveloped->cert;
+                                crls = p7->d.signed_and_enveloped->crl;
+                        }
                         break;
                 default:
                         break;