pkcs7: Prevent NULL pointer dereference, since sinfo is not always set.

commit 68a1fdbbf8bd3378325e45c19e167a165f9ffc3a upstream.

The ASN.1 parser does not necessarily set the sinfo field,
this patch prevents a NULL pointer dereference on broken
input.

Fixes: 99db44350672 ("PKCS#7: Appropriately restrict authenticated attributes and content type")
Signed-off-by: Eric Sesterhenn <eric.sesterhenn@x41-dsec.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c
index 8f3056cd03991ddf820c3d8442d35daf3db7ee84..2516e97c58f1b5d98efb0d88692bfe167baaae97 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_parser.c
+++ b/crypto/asymmetric_keys/pkcs7_parser.c
@@ -90,6 +90,9 @@ static int pkcs7_check_authattrs(struct pkcs7_message *msg)
        bool want;
 
        sinfo = msg->signed_infos;
+       if (!sinfo)
+               goto inconsistent;
+
        if (sinfo->authattrs) {
                want = true;
                msg->have_authattrs = true;