chrony/chrony-select-timeout.patch

95 lines
3.1 KiB
Diff

commit d0b24860363a3704e28569ce9a6987717834edea
Author: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue Dec 5 11:08:24 2017 +0100
client: don't call select() with invalid timeout
If the system clock was stepped forward after chronyc sent a request and
before it read the clock in order to calculate the receive timeout,
select() could be called with a negative timeout, which resulted in an
infinite loop waiting for select() to succeed.
Fix the submit_request() function to not call select() with a negative
timeout. Also, return immediately on any error of select().
diff --git a/client.c b/client.c
index 5c3a99e..4e23158 100644
--- a/client.c
+++ b/client.c
@@ -1394,9 +1394,16 @@ submit_request(CMD_Request *request, CMD_Reply *reply)
timeout = initial_timeout / 1000.0 * (1U << (n_attempts - 1)) -
UTI_DiffTimespecsToDouble(&ts_now, &ts_start);
- UTI_DoubleToTimeval(timeout, &tv);
DEBUG_LOG("Timeout %f seconds", timeout);
+ /* Avoid calling select() with an invalid timeout */
+ if (timeout <= 0.0) {
+ new_attempt = 1;
+ continue;
+ }
+
+ UTI_DoubleToTimeval(timeout, &tv);
+
FD_ZERO(&rdfd);
FD_ZERO(&wrfd);
FD_ZERO(&exfd);
@@ -1410,6 +1417,7 @@ submit_request(CMD_Request *request, CMD_Reply *reply)
if (select_status < 0) {
DEBUG_LOG("select failed : %s", strerror(errno));
+ return 0;
} else if (select_status == 0) {
/* Timeout must have elapsed, try a resend? */
new_attempt = 1;
commit 6863e43269fe27ce2744eb643295f31c00ec176d
Author: Miroslav Lichvar <mlichvar@redhat.com>
Date: Tue Dec 12 11:03:04 2017 +0100
client: avoid reading clock after sending request
If chronyc sent a request which caused chronyd to step the clock (e.g.
makestep, settime) and the second reading of the clock before calling
select() to wait for a response happened after the clock was stepped, a
new request could be sent immediately and chronyd would process the same
command twice. If the second request failed (e.g. a settime request too
close to the first request), chronyc would report an error.
Change the submit_request() function to read the clock only once per
select() to wait for the first response even when the clock was stepped.
diff --git a/client.c b/client.c
index a04dcb8..7d1e346 100644
--- a/client.c
+++ b/client.c
@@ -1347,15 +1347,15 @@ submit_request(CMD_Request *request, CMD_Reply *reply)
new_attempt = 1;
do {
+ if (gettimeofday(&tv, NULL))
+ return 0;
+
if (new_attempt) {
new_attempt = 0;
if (n_attempts > max_retries)
return 0;
- if (gettimeofday(&tv, NULL))
- return 0;
-
UTI_TimevalToTimespec(&tv, &ts_start);
UTI_GetRandomBytes(&request->sequence, sizeof (request->sequence));
@@ -1383,9 +1383,6 @@ submit_request(CMD_Request *request, CMD_Reply *reply)
DEBUG_LOG("Sent %d bytes", command_length);
}
- if (gettimeofday(&tv, NULL))
- return 0;
-
UTI_TimevalToTimespec(&tv, &ts_now);
/* Check if the clock wasn't stepped back */