pkcs7: fix check for self-signed certificate

pkcs7_validate_trust_one() used 'x509->next == x509' to identify a
self-signed certificate.  That's wrong; ->next is simply the link in the
linked list of certificates in the PKCS#7 message.  It should be
checking ->signer instead.  Fix it.

Fortunately this didn't actually matter because when we re-visited
'x509' on the next iteration via 'x509->signer', it was already seen and
not verified, so we returned -ENOKEY anyway.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>

diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index f6a009d88a33fb550654b11d2cfc4460c733a049..1f4e25f10049c2645c2a421b07bb21fdaf1c0857 100644 (file)
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -69,7 +69,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
                 /* Self-signed certificates form roots of their own, and if we
                  * don't know them, then we can't accept them.
                  */
-               if (x509->next == x509) {
+               if (x509->signer == x509) {
                        kleave(" = -ENOKEY [unknown self-signed]");
                        return -ENOKEY;
                }