dnsmasq: fix a race condition possibly leading to lockup
SVN-Revision: 42225
This commit is contained in:
Steven Barth
parent
f66a0912f7
commit
0f49b1940e
2 changed files with 278 additions and 1 deletions
|
|
@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
|
|||
|
||||
PKG_NAME:=dnsmasq
|
||||
PKG_VERSION:=2.71
|
||||
PKG_RELEASE:=3
|
||||
PKG_RELEASE:=4
|
||||
|
||||
PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
|
||||
PKG_SOURCE_URL:=http://thekelleys.org.uk/dnsmasq
|
||||
|
|
|
|||
|
|
@ -0,0 +1,277 @@
|
|||
From a0358e5ddbc1ef3dec791f11f95f5dbe56087a5e Mon Sep 17 00:00:00 2001
|
||||
From: Simon Kelley <simon@thekelleys.org.uk>
|
||||
Date: Sat, 7 Jun 2014 13:38:48 +0100
|
||||
Subject: [PATCH] Handle async notification of address changes using the event
|
||||
system.
|
||||
|
||||
---
|
||||
CHANGELOG | 4 ++++
|
||||
src/bpf.c | 6 +++---
|
||||
src/dhcp6.c | 10 ----------
|
||||
src/dnsmasq.c | 13 +++++++++++--
|
||||
src/dnsmasq.h | 6 ++++--
|
||||
src/netlink.c | 39 ++++++++++-----------------------------
|
||||
src/network.c | 11 +++--------
|
||||
7 files changed, 35 insertions(+), 54 deletions(-)
|
||||
|
||||
--- a/CHANGELOG
|
||||
+++ b/CHANGELOG
|
||||
@@ -15,6 +15,10 @@ version 2.71
|
||||
regression introduced in 2.69. Thanks to James Hunt and
|
||||
the Ubuntu crowd for assistance in fixing this.
|
||||
|
||||
+ Fix race condition which could lock up dnsmasq when an
|
||||
+ interface goes down and up rapidly. Thanks to Conrad
|
||||
+ Kostecki for helping to chase this down.
|
||||
+
|
||||
|
||||
version 2.70
|
||||
Fix crash, introduced in 2.69, on TCP request when dnsmasq
|
||||
--- a/src/bpf.c
|
||||
+++ b/src/bpf.c
|
||||
@@ -376,7 +376,7 @@ void route_init(void)
|
||||
die(_("cannot create PF_ROUTE socket: %s"), NULL, EC_BADNET);
|
||||
}
|
||||
|
||||
-void route_sock(time_t now)
|
||||
+void route_sock(void)
|
||||
{
|
||||
struct if_msghdr *msg;
|
||||
int rc = recv(daemon->routefd, daemon->packet, daemon->packet_buff_sz, 0);
|
||||
@@ -401,7 +401,7 @@ void route_sock(time_t now)
|
||||
else if (msg->ifm_type == RTM_NEWADDR)
|
||||
{
|
||||
del_family = 0;
|
||||
- newaddress(now);
|
||||
+ send_newaddr();
|
||||
}
|
||||
else if (msg->ifm_type == RTM_DELADDR)
|
||||
{
|
||||
@@ -439,7 +439,7 @@ void route_sock(time_t now)
|
||||
of += sizeof(long) - (diff & (sizeof(long) - 1));
|
||||
}
|
||||
|
||||
- newaddress(now);
|
||||
+ send_newaddr();
|
||||
}
|
||||
}
|
||||
|
||||
--- a/src/dnsmasq.c
|
||||
+++ b/src/dnsmasq.c
|
||||
@@ -917,10 +917,10 @@ int main (int argc, char **argv)
|
||||
|
||||
#if defined(HAVE_LINUX_NETWORK)
|
||||
if (FD_ISSET(daemon->netlinkfd, &rset))
|
||||
- netlink_multicast(now);
|
||||
+ netlink_multicast();
|
||||
#elif defined(HAVE_BSD_NETWORK)
|
||||
if (FD_ISSET(daemon->routefd, &rset))
|
||||
- route_sock(now);
|
||||
+ route_sock();
|
||||
#endif
|
||||
|
||||
/* Check for changes to resolv files once per second max. */
|
||||
@@ -1037,6 +1037,11 @@ void send_alarm(time_t event, time_t now
|
||||
}
|
||||
}
|
||||
|
||||
+void send_newaddr(void)
|
||||
+{
|
||||
+ send_event(pipewrite, EVENT_NEWADDR, 0, NULL);
|
||||
+}
|
||||
+
|
||||
void send_event(int fd, int event, int data, char *msg)
|
||||
{
|
||||
struct event_desc ev;
|
||||
@@ -1230,6 +1235,10 @@ static void async_event(int pipe, time_t
|
||||
if (daemon->log_file != NULL)
|
||||
log_reopen(daemon->log_file);
|
||||
break;
|
||||
+
|
||||
+ case EVENT_NEWADDR:
|
||||
+ newaddress(now);
|
||||
+ break;
|
||||
|
||||
case EVENT_TERM:
|
||||
/* Knock all our children on the head. */
|
||||
--- a/src/dnsmasq.h
|
||||
+++ b/src/dnsmasq.h
|
||||
@@ -165,6 +165,7 @@ struct event_desc {
|
||||
#define EVENT_LUA_ERR 19
|
||||
#define EVENT_TFTP_ERR 20
|
||||
#define EVENT_INIT 21
|
||||
+#define EVENT_NEWADDR 22
|
||||
|
||||
/* Exit codes. */
|
||||
#define EC_GOOD 0
|
||||
@@ -1289,6 +1290,7 @@ unsigned char *extended_hwaddr(int hwtyp
|
||||
int make_icmp_sock(void);
|
||||
int icmp_ping(struct in_addr addr);
|
||||
#endif
|
||||
+void send_newaddr(void);
|
||||
void send_alarm(time_t event, time_t now);
|
||||
void send_event(int fd, int event, int data, char *msg);
|
||||
void clear_cache_and_reload(time_t now);
|
||||
@@ -1297,7 +1299,7 @@ void poll_resolv(int force, int do_reloa
|
||||
/* netlink.c */
|
||||
#ifdef HAVE_LINUX_NETWORK
|
||||
void netlink_init(void);
|
||||
-void netlink_multicast(time_t now);
|
||||
+void netlink_multicast(void);
|
||||
#endif
|
||||
|
||||
/* bpf.c */
|
||||
@@ -1306,7 +1308,7 @@ void init_bpf(void);
|
||||
void send_via_bpf(struct dhcp_packet *mess, size_t len,
|
||||
struct in_addr iface_addr, struct ifreq *ifr);
|
||||
void route_init(void);
|
||||
-void route_sock(time_t now);
|
||||
+void route_sock(void);
|
||||
#endif
|
||||
|
||||
/* bpf.c or netlink.c */
|
||||
--- a/src/netlink.c
|
||||
+++ b/src/netlink.c
|
||||
@@ -38,7 +38,7 @@
|
||||
static struct iovec iov;
|
||||
static u32 netlink_pid;
|
||||
|
||||
-static int nl_async(struct nlmsghdr *h);
|
||||
+static void nl_async(struct nlmsghdr *h);
|
||||
|
||||
void netlink_init(void)
|
||||
{
|
||||
@@ -142,7 +142,7 @@ int iface_enumerate(int family, void *pa
|
||||
struct nlmsghdr *h;
|
||||
ssize_t len;
|
||||
static unsigned int seq = 0;
|
||||
- int callback_ok = 1, newaddr = 0;
|
||||
+ int callback_ok = 1;
|
||||
|
||||
struct {
|
||||
struct nlmsghdr nlh;
|
||||
@@ -191,21 +191,10 @@ int iface_enumerate(int family, void *pa
|
||||
if (h->nlmsg_seq != seq || h->nlmsg_pid != netlink_pid || h->nlmsg_type == NLMSG_ERROR)
|
||||
{
|
||||
/* May be multicast arriving async */
|
||||
- if (nl_async(h))
|
||||
- {
|
||||
- newaddr = 1;
|
||||
- enumerate_interfaces(1); /* reset */
|
||||
- }
|
||||
+ nl_async(h);
|
||||
}
|
||||
else if (h->nlmsg_type == NLMSG_DONE)
|
||||
- {
|
||||
- /* handle async new interface address arrivals, these have to be done
|
||||
- after we complete as we're not re-entrant */
|
||||
- if (newaddr)
|
||||
- newaddress(dnsmasq_time());
|
||||
-
|
||||
- return callback_ok;
|
||||
- }
|
||||
+ return callback_ok;
|
||||
else if (h->nlmsg_type == RTM_NEWADDR && family != AF_UNSPEC && family != AF_LOCAL)
|
||||
{
|
||||
struct ifaddrmsg *ifa = NLMSG_DATA(h);
|
||||
@@ -330,11 +319,11 @@ int iface_enumerate(int family, void *pa
|
||||
}
|
||||
}
|
||||
|
||||
-void netlink_multicast(time_t now)
|
||||
+void netlink_multicast(void)
|
||||
{
|
||||
ssize_t len;
|
||||
struct nlmsghdr *h;
|
||||
- int flags, newaddr = 0;
|
||||
+ int flags;
|
||||
|
||||
/* don't risk blocking reading netlink messages here. */
|
||||
if ((flags = fcntl(daemon->netlinkfd, F_GETFL)) == -1 ||
|
||||
@@ -343,24 +332,19 @@ void netlink_multicast(time_t now)
|
||||
|
||||
if ((len = netlink_recv()) != -1)
|
||||
for (h = (struct nlmsghdr *)iov.iov_base; NLMSG_OK(h, (size_t)len); h = NLMSG_NEXT(h, len))
|
||||
- if (nl_async(h))
|
||||
- newaddr = 1;
|
||||
+ nl_async(h);
|
||||
|
||||
/* restore non-blocking status */
|
||||
fcntl(daemon->netlinkfd, F_SETFL, flags);
|
||||
-
|
||||
- if (newaddr)
|
||||
- newaddress(now);
|
||||
}
|
||||
|
||||
-static int nl_async(struct nlmsghdr *h)
|
||||
+static void nl_async(struct nlmsghdr *h)
|
||||
{
|
||||
if (h->nlmsg_type == NLMSG_ERROR)
|
||||
{
|
||||
struct nlmsgerr *err = NLMSG_DATA(h);
|
||||
if (err->error != 0)
|
||||
my_syslog(LOG_ERR, _("netlink returns error: %s"), strerror(-(err->error)));
|
||||
- return 0;
|
||||
}
|
||||
else if (h->nlmsg_pid == 0 && h->nlmsg_type == RTM_NEWROUTE)
|
||||
{
|
||||
@@ -385,18 +369,15 @@ static int nl_async(struct nlmsghdr *h)
|
||||
else if (daemon->rfd_save && daemon->rfd_save->refcount != 0)
|
||||
fd = daemon->rfd_save->fd;
|
||||
else
|
||||
- return 0;
|
||||
+ return;
|
||||
|
||||
while(sendto(fd, daemon->packet, daemon->packet_len, 0,
|
||||
&daemon->srv_save->addr.sa, sa_len(&daemon->srv_save->addr)) == -1 && retry_send());
|
||||
}
|
||||
}
|
||||
- return 0;
|
||||
}
|
||||
else if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR)
|
||||
- return 1; /* clever bind mode - rescan */
|
||||
-
|
||||
- return 0;
|
||||
+ send_newaddr();
|
||||
}
|
||||
#endif
|
||||
|
||||
--- a/src/network.c
|
||||
+++ b/src/network.c
|
||||
@@ -551,7 +551,7 @@ static int iface_allowed_v4(struct in_ad
|
||||
int enumerate_interfaces(int reset)
|
||||
{
|
||||
static struct addrlist *spare = NULL;
|
||||
- static int done = 0, active = 0;
|
||||
+ static int done = 0;
|
||||
struct iface_param param;
|
||||
int errsave, ret = 1;
|
||||
struct addrlist *addr, *tmp;
|
||||
@@ -570,14 +570,11 @@ int enumerate_interfaces(int reset)
|
||||
return 1;
|
||||
}
|
||||
|
||||
- if (done || active)
|
||||
+ if (done)
|
||||
return 1;
|
||||
|
||||
done = 1;
|
||||
|
||||
- /* protect against recusive calls from iface_enumerate(); */
|
||||
- active = 1;
|
||||
-
|
||||
if ((param.fd = socket(PF_INET, SOCK_DGRAM, 0)) == -1)
|
||||
return 0;
|
||||
|
||||
@@ -677,10 +674,8 @@ int enumerate_interfaces(int reset)
|
||||
}
|
||||
|
||||
errno = errsave;
|
||||
-
|
||||
spare = param.spare;
|
||||
- active = 0;
|
||||
-
|
||||
+
|
||||
return ret;
|
||||
}
|
||||
|
||||
Loading…
Reference in a new issue