Tolerate a zero length ticket nonce #3957
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TLSv1.3 draft-21 requires the ticket nonce to be at least 1 byte in length. However NSS sends a zero length nonce. This is actually ok because the next draft will allow zero length nonces anyway, so we should tolerate this.
richsalz
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Jul 18, 2017
levitte
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Jul 18, 2017
TLSv1.3 draft-21 requires the ticket nonce to be at least 1 byte in length. However NSS sends a zero length nonce. This is actually ok because the next draft will allow zero length nonces anyway, so we should tolerate this. Reviewed-by: Rich Salz <rsalz@openssl.org> (Merged from #3957)
kaduk
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Jul 18, 2017
| @@ -2422,7 +2422,6 @@ MSG_PROCESS_RETURN tls_process_new_session_ticket(SSL *s, PACKET *pkt) | |||
| || (SSL_IS_TLS13(s) | |||
| && (!PACKET_get_net_4(pkt, &age_add) | |||
| || !PACKET_get_length_prefixed_1(pkt, &nonce) | |||
| || PACKET_remaining(&nonce) == 0 | |||
| || !PACKET_memdup(&nonce, &s->session->ext.tick_nonce, | |||
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(PACKET_memdup() does not write to the data or length output parameters when PACKET_remaining(pkt) is zero. This is vaguely tolerable here because the session's extensions block is initialized to zero, but is vaguely disquieting.)
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Hmm. Maybe it should?
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Whoops, I was reading too fast and only looked at the body of the "length == 1" conditional -- *data and *len are initialized unconditionally in PACKET_memdup(), so there's nothing to do.
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I already pushed this before @kaduk's comment, so closing. If there are any follow on actions it will have to be a different PR. |
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TLSv1.3 draft-21 requires the ticket nonce to be at least 1 byte in length.
However NSS sends a zero length nonce. This is actually ok because the next
draft will allow zero length nonces anyway, so we should tolerate this.