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ntp: move authentication calls in transmit_packet()

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Move the calls resetting and generating authentication data out of the
loop checking for unique TX timestamp. This allows the timestamps to be
manipulated after the check.
This commit is contained in:
Miroslav Lichvar 2021-10-14 11:52:21 +02:00
parent 14b8df3702
commit 7a80647fb4
1 changed files with 17 additions and 17 deletions
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24
ntp_core.c
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@ -1054,10 +1054,10 @@ transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
UTI_ZeroNtp64(&message.receive_ts);
}
do {
if (!parse_packet(&message, NTP_HEADER_LENGTH, &info))
return 0;
do {
/* Prepare random bits which will be added to the transmit timestamp */
UTI_GetNtp64Fuzz(&ts_fuzz, precision);
@ -1072,6 +1072,17 @@ transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
UTI_TimespecToNtp64(interleaved ? &local_tx->ts : &local_transmit,
&message.transmit_ts, &ts_fuzz);
/* Do not send a packet with a non-zero transmit timestamp which is
equal to any of the following timestamps:
- receive (to allow reliable detection of the interleaved mode)
- originate (to prevent the packet from being its own valid response
in the symmetric mode)
- previous transmit (to invalidate responses to the previous packet)
(the precision must be at least -30 to prevent an infinite loop!) */
} while (!UTI_IsZeroNtp64(&message.transmit_ts) &&
UTI_IsEqualAnyNtp64(&message.transmit_ts, &message.receive_ts,
&message.originate_ts, local_ntp_tx));
/* Generate the authentication data */
if (auth) {
if (!NAU_GenerateRequestAuth(auth, &message, &info)) {
@ -1086,17 +1097,6 @@ transmit_packet(NTP_Mode my_mode, /* The mode this machine wants to be */
}
}
/* Do not send a packet with a non-zero transmit timestamp which is
equal to any of the following timestamps:
- receive (to allow reliable detection of the interleaved mode)
- originate (to prevent the packet from being its own valid response
in the symmetric mode)
- previous transmit (to invalidate responses to the previous packet)
(the precision must be at least -30 to prevent an infinite loop!) */
} while (!UTI_IsZeroNtp64(&message.transmit_ts) &&
UTI_IsEqualAnyNtp64(&message.transmit_ts, &message.receive_ts,
&message.originate_ts, local_ntp_tx));
if (request_info && request_info->length < info.length) {
DEBUG_LOG("Response longer than request req_len=%d res_len=%d",
request_info->length, info.length);