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Add clarifications ("comments") to three places where it wasn't

obvious why it is implemented this way.  The whole idea of constraints
is to isolate them as much as possible, in a semi-paranoid way.
OK rzalamena@
OPENBSD_6_1
reyk 8 years ago
parent
commit
5ec8dcba4c
1 changed files with 19 additions and 2 deletions
  1. +19
    -2
      src/usr.sbin/ntpd/constraint.c

+ 19
- 2
src/usr.sbin/ntpd/constraint.c View File

@ -1,4 +1,4 @@
/* $OpenBSD: constraint.c,v 1.30 2016/07/13 16:35:47 jsing Exp $ */
/* $OpenBSD: constraint.c,v 1.31 2016/09/14 09:26:10 reyk Exp $ */
/*
* Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@ -320,7 +320,12 @@ priv_constraint_child(struct constraint *cstr, struct ntp_addr_msg *am,
if (pledge("stdio inet", NULL) == -1)
fatal("pledge");
/* Get name and set process title */
/*
* Get the IP address as name and set the process title accordingly.
* This only converts an address into a string and does not trigger
* any DNS operation, so it is safe to be called without the dns
* pledge.
*/
if (getnameinfo((struct sockaddr *)&cstr->addr->ss,
SA_LEN((struct sockaddr *)&cstr->addr->ss),
addr, sizeof(addr), NULL, 0,
@ -339,6 +344,12 @@ priv_constraint_child(struct constraint *cstr, struct ntp_addr_msg *am,
close(pipes[1]);
(void)closefrom(CONSTRAINT_PASSFD + 1);
/*
* Set the close-on-exec flag to prevent leaking the communication
* channel to any exec'ed child. In theory this could never happen,
* constraints don't exec children and pledge() prevents it,
* but we keep it as a safety belt; especially for portability.
*/
if (fcntl(CONSTRAINT_PASSFD, F_SETFD, FD_CLOEXEC) == -1)
fatal("%s fcntl F_SETFD", __func__);
@ -864,6 +875,12 @@ httpsdate_request(struct httpsdate *httpsdate, struct timeval *when)
if (tls_configure(httpsdate->tls_ctx, httpsdate->tls_config) == -1)
goto fail;
/*
* libtls expects an address string, which can also be a DNS name,
* but we pass a pre-resolved IP address string in tls_addr so it
* does not trigger any DNS operation and is safe to be called
* without the dns pledge.
*/
if (tls_connect_servername(httpsdate->tls_ctx, httpsdate->tls_addr,
httpsdate->tls_port, httpsdate->tls_hostname) == -1) {
log_debug("tls connect failed: %s (%s): %s",


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