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Commit ca244224 authored by Sébastien Luttringer's avatar Sébastien Luttringer
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upgpkg: 2.0.7-1

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01-fix-FS#48318.patch deleted 100644 → 0
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View file @ 6c42556b
From 1f70d2ba45e2b067777d5386b8d3f2e09be9118b Mon Sep 17 00:00:00 2001
From: Hironobu Ishii <ishii.hironobu@jp.fujitsu.com>
Date: Tue, 2 Feb 2016 23:01:41 +0900
Subject: ulogd: restructures signal handling by self-pipe trick
ulogd had a critical bug that is calling Async-Signal-Unsafe functions
in signal hander context.
- Most of libc functions like fopen(), malloc() are Async-Signal-Unsafe.
So you should not call these functions in signal handler context.
- Calling pluginstances in signal handler context is danger.
For implementer of pluginstances, it is very hard to recognize their
functions are called in signal handler context.
To solve the issue, I restructured signal handling by self-pipe trick.
For more detail on self-pipe trick, please see the following.
https://lwn.net/Articles/177897/
This patch will solve various symptoms like following.
- Deadlock
- Segmentation fault caused by libc management data corruption,
- Other unpredictable behavior.
Deadlock example
================
This bug was already filed at:
https://bugzilla.netfilter.org/show_bug.cgi?id=1030
I also hit this bug. The backtrace of this issue is following.
In this case, main thread was calling ctime(),
and signal handler called localtime_r().
That caused the dead lock while getting tzset_lock in __tz_convert().
Because vsyslog() is Async-Signal-Unsafe function, we cannot call
this function in signal handler context.
(gdb) bt
#0 __lll_lock_wait_private () at ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:95
#1 0x00007f3c3fc7e4ac in _L_lock_2462 () at tzset.c:621
#2 0x00007f3c3fc7e2e7 in __tz_convert (timer=0x7f3c3ff8bf00 <tzset_lock>,
timer@entry=0x7fffcfa923b8, use_localtime=use_localtime@entry=1,
tp=tp@entry=0x7fffcfa92400) at tzset.c:624
#3 0x00007f3c3fc7c28d in __localtime_r (t=t@entry=0x7fffcfa923b8,
tp=tp@entry=0x7fffcfa92400) at localtime.c:32
#4 0x00007f3c3fcbf1ba in __GI___vsyslog_chk (pri=<optimized out>, flag=1,
fmt=0x406fa8 "signal received, calling pluginstances\n", ap=0x7fffcfa924a0)
at ../misc/syslog.c:199
#5 0x00000000004037b5 in __ulogd_log ()
#6 0x00000000004047be in signal_handler ()
#7 <signal handler called>
#8 0x00007f3c3fcb62f5 in __GI___xstat (vers=<optimized out>,
name=0x7f3c3fd4b2c3 "/etc/localtime", buf=0x7fffcfa92c10)
at ../sysdeps/unix/sysv/linux/wordsize-64/xstat.c:37
#9 0x00007f3c3fc7e5f6 in __tzfile_read (file=file@entry=0x7f3c3fd4b2c3 "/etc/localtime",
extra=extra@entry=0, extrap=extrap@entry=0x0) at tzfile.c:170
#10 0x00007f3c3fc7d954 in tzset_internal (always=<optimized out>,
explicit=explicit@entry=1) at tzset.c:444
#11 0x00007f3c3fc7e303 in __tz_convert (timer=0x7fffcfa92d50,
use_localtime=use_localtime@entry=1, tp=tp@entry=0x7f3c3ff8ed80 <_tmbuf>)
at tzset.c:629
#12 0x00007f3c3fc7c2a1 in __GI_localtime (t=<optimized out>) at localtime.c:42
#13 0x00007f3c3fc7c1f9 in ctime (t=<optimized out>) at ctime.c:27
#14 0x00007f3c3e180ec2 in ?? ()
#15 0x0000000056a100c2 in ?? ()
#16 0xf8570f79d4fc4200 in ?? ()
#17 0x000000000209bec0 in ?? ()
#18 0x00007f3c4059f1f8 in ?? ()
#19 0x000000000000003c in ?? ()
#20 0x0000000000404952 in ulogd_propagate_results ()
#21 0x00007f3c3f9cc203 in ?? ()
#22 0x0000000000000000 in ?? ()
Segmentation fault in free()
============================
>From my experience, I think this was caused by some routine called
malloc()/free() in signal handler context.
By that, malloc() management data became inconsistent.
As a result, free() made a wrong dereference.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 __GI___libc_free (mem=0x7f430f011000) at malloc.c:2903
2903 if (chunk_is_mmapped(p)) /* release mmapped memory. */
(gdb) bt
#0 __GI___libc_free (mem=0x7f430f011000) at malloc.c:2903
#1 0x00007f430e68affa in __GI__IO_free_backup_area (fp=fp@entry=0x742500)
at genops.c:210
#2 0x00007f430e68a795 in _IO_new_file_overflow (f=0x742500, ch=-1) at fileops.c:849
#3 0x00007f430e689511 in _IO_new_file_xsputn (f=0x742500, data=<optimized out>, n=15)
at fileops.c:1372
#4 0x00007f430e65aa4d in _IO_vfprintf_internal (s=s@entry=0x742500,
format=<optimized out>, format@entry=0x7f430cbc4008 "%.15s %s %s",
ap=ap@entry=0x7fff456ece38) at vfprintf.c:1635
#5 0x00007f430e71d615 in ___fprintf_chk (fp=0x742500, flag=flag@entry=1,
format=format@entry=0x7f430cbc4008 "%.15s %s %s") at fprintf_chk.c:36
#6 0x00007f430cbc3f04 in fprintf (__fmt=0x7f430cbc4008 "%.15s %s %s",
__stream=<optimized out>) at /usr/include/bits/stdio2.h:97
#7 _output_logemu (upi=0x74e5a0) at ulogd_output_LOGEMU.c:102
#8 0x0000000000404952 in ulogd_propagate_results ()
#9 0x00007f430e40f203 in interp_packet (ldata=0x7fff456ed060, pf_family=2 '\002',
upi=0x74a6b0) at ulogd_inppkt_NFLOG.c:400
#10 msg_cb (gh=<optimized out>, nfmsg=0x7f430efe2020, nfa=0x7fff456ed060, data=0x74a6b0)
at ulogd_inppkt_NFLOG.c:483
#11 0x00007f430e20a307 in __nflog_rcv_pkt (nlh=<optimized out>, nfa=<optimized out>,
data=<optimized out>) at libnetfilter_log.c:160
#12 0x00007f430e0056b7 in __nfnl_handle_msg (len=268, nlh=0x7f430efe2010, h=0x74e8e0)
at libnfnetlink.c:1236
#13 nfnl_handle_packet (h=0x74e8e0, buf=0x7f430efe2010 "\f\001", len=<optimized out>)
at libnfnetlink.c:1256
#14 0x00007f430e20a508 in nflog_handle_packet (h=<optimized out>, buf=<optimized out>,
len=<optimized out>) at libnetfilter_log.c:323
#15 0x00007f430e40eaed in nful_read_cb (fd=<optimized out>, what=<optimized out>,
param=0x74a6b0) at ulogd_inppkt_NFLOG.c:463
#16 0x0000000000404ee0 in ulogd_select_main ()
#17 0x0000000000402b17 in main ()
Signed-off-by: Hironobu Ishii <ishii.hironobu@jp.fujitsu.com>
---
src/ulogd.c | 132 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 125 insertions(+), 7 deletions(-)
diff --git a/src/ulogd.c b/src/ulogd.c
index 958c30a..c8d9376 100644
--- a/src/ulogd.c
+++ b/src/ulogd.c
@@ -90,6 +90,29 @@ static int info_mode = 0;
static int verbose = 0;
static int created_pidfile = 0;
+/*
+ * Using self-pipe trick to handle signals safely.
+ * (To avoid calling Async-Signal-Unsafe functions in signal handler.)
+ *
+ * cf. https://lwn.net/Articles/177897/
+ *
+ * Capacity of pipe(2) buffer is >= 4096.
+ */
+static int signal_channel[2] = { -1, -1 }; /* initialize with invalid fd */
+#define SIGNAL_RX_FD (signal_channel[0]) /* main thread select() this fd */
+#define SIGNAL_TX_FD (signal_channel[1]) /* signal handler writes to this fd */
+
+static void signal_handler(int signal);
+static void sigterm_handler_task(int signal);
+static void signal_handler_task(int signal);
+
+static int signal_channel_callback(int fd, unsigned int what, void *data);
+static struct ulogd_fd signal_channel_ulogfd = {
+ .when = ULOGD_FD_READ,
+ .cb = &signal_channel_callback,
+ .data = &signal_channel_ulogfd,
+};
+
/* linked list for all registered plugins */
static LLIST_HEAD(ulogd_plugins);
/* linked list for all plugins handle */
@@ -387,6 +410,80 @@ void ulogd_register_plugin(struct ulogd_plugin *me)
}
/***********************************************************************
+ * UTILITY FUNCTIONS FOR SIGNAL HANDLING
+ ***********************************************************************/
+static void call_signal_handler_tasks(int sig)
+{
+ /* Deliver signals */
+ switch (sig) {
+ case SIGTERM:
+ case SIGINT:
+ sigterm_handler_task(sig);
+ break;
+ case SIGHUP:
+ case SIGALRM:
+ case SIGUSR1:
+ case SIGUSR2:
+ signal_handler_task(sig);
+ break;
+ default:
+ break;
+ }
+}
+
+static int signal_channel_callback(int fd, unsigned int what, void *data)
+{
+ int ret;
+ unsigned char c;
+
+ while ((ret = read(fd, &c, 1)) > 0) {
+ call_signal_handler_tasks((int)c);
+ }
+ return 0;
+}
+
+static int create_signal_channel(void)
+{
+ int ret;
+ long flags;
+
+ if ((ret = pipe(signal_channel)) < 0)
+ return ret;
+
+ /* SIGNAL_RX_FD, channel[0] */
+ if ((flags = fcntl(SIGNAL_RX_FD, F_GETFL)) < 0)
+ goto err_exit;
+ flags |= O_NONBLOCK;
+ if ( fcntl(SIGNAL_RX_FD, F_SETFL, flags) < 0 )
+ goto err_exit;
+
+ /* SIGNAL_TX_FD, channel[1] */
+ if ((flags = fcntl(SIGNAL_TX_FD, F_GETFL)) < 0)
+ goto err_exit;
+ flags |= O_NONBLOCK;
+ if ( fcntl(SIGNAL_TX_FD, F_SETFL, flags) < 0 )
+ goto err_exit;
+
+ /* register SIGNAL_RX_FD to ulogd */
+ signal_channel_ulogfd.fd = SIGNAL_RX_FD;
+ ulogd_register_fd(&signal_channel_ulogfd);
+
+ return 0;
+
+err_exit:
+ if (SIGNAL_RX_FD >= 0) {
+ (void)close(SIGNAL_RX_FD);
+ SIGNAL_RX_FD = -1;
+ }
+ if (SIGNAL_TX_FD >= 0) {
+ (void)close(SIGNAL_TX_FD);
+ SIGNAL_TX_FD = -1;
+ }
+ return -1;
+}
+
+
+/***********************************************************************
* MAIN PROGRAM
***********************************************************************/
@@ -925,7 +1022,6 @@ static void ulogd_main_loop(void)
struct timeval *next = NULL;
while (1) {
- /* XXX: signal blocking? */
if (next != NULL && !timerisset(next))
next = ulogd_do_timer_run(&next_alarm);
else
@@ -1225,7 +1321,19 @@ static void stop_stack()
}
-static void sigterm_handler(int signal)
+/* This is a real SIGTERM, SIGINT, SIGHUP, SIGALRM, SIGUSR1, SIGUSR2 handler */
+static void signal_handler(int signal)
+{
+ unsigned char c = (unsigned char)signal;
+
+ (void)write(SIGNAL_TX_FD, &c, 1);
+}
+
+/* This is NOT a real signal handler.
+ * It is called in ulogd_main_loop() to avoid
+ * calling Async-Signal-UnSafe functions in signal handler.
+ */
+static void sigterm_handler_task(int signal)
{
ulogd_log(ULOGD_NOTICE, "Terminal signal received, exiting\n");
@@ -1255,7 +1363,12 @@ static void sigterm_handler(int signal)
exit(0);
}
-static void signal_handler(int signal)
+
+/* This is NOT a real signal handler.
+ * It is called in ulogd_main_loop() to avoid
+ * calling Async-Signal-UnSafe functions in signal handler.
+ */
+static void signal_handler_task(int signal)
{
ulogd_log(ULOGD_NOTICE, "signal received, calling pluginstances\n");
@@ -1269,7 +1382,7 @@ static void signal_handler(int signal)
fprintf(stderr,
"ERROR: can't open logfile %s: %s\n",
ulogd_logfile, strerror(errno));
- sigterm_handler(signal);
+ sigterm_handler_task(signal);
}
}
@@ -1464,8 +1577,13 @@ int main(int argc, char* argv[])
}
}
- signal(SIGTERM, &sigterm_handler);
- signal(SIGINT, &sigterm_handler);
+ if (create_signal_channel() < 0) {
+ ulogd_log(ULOGD_FATAL, "can't create signal channel\n");
+ warn_and_exit(daemonize);
+ }
+
+ signal(SIGTERM, &signal_handler);
+ signal(SIGINT, &signal_handler);
signal(SIGHUP, &signal_handler);
signal(SIGALRM, &signal_handler);
signal(SIGUSR1, &signal_handler);
@@ -1477,6 +1595,6 @@ int main(int argc, char* argv[])
ulogd_main_loop();
/* hackish, but result is the same */
- sigterm_handler(SIGTERM);
+ sigterm_handler_task(SIGTERM);
return(0);
}
--
cgit v0.11.2
PKGBUILD
+ 7
− 10
View file @ ca244224
......@@ -3,8 +3,8 @@
# Contributor: Dale Blount <dale@archlinux.org>
pkgname=ulogd
pkgver=2.0.5
pkgrel=8
pkgver=2.0.7
pkgrel=1
pkgdesc='Userspace Packet Logging for netfilter'
arch=('x86_64')
url='https://www.netfilter.org/projects/ulogd/'
......@@ -27,19 +27,16 @@ optdepends=('libmariadbclient: MySQL databases support'
'libdbi: DBI abstraction databases support'
'libpcap: PCAP output support'
'jansson: JSON output support')
validpgpkeys=('57FF5E9C9AA67A860B557AF7A4111F89BB5F58CC') # Netfilter Core Team
# 2016-11-03: https sources download is broken with curl
source=("http://www.netfilter.org/projects/ulogd/files/$pkgname-$pkgver.tar.bz2"{,.sig}
validpgpkeys=('C09DB2063F1D7034BA6152ADAB4655A126D292E4') # Netfilter Core Team
source=("https://www.netfilter.org/projects/ulogd/files/$pkgname-$pkgver.tar.bz2"{,.sig}
"$pkgname.logrotate"
"$pkgname.conf"
"$pkgname.service"
'01-fix-FS#48318.patch')
md5sums=('f0f8fe1371fa28b5e06cb16aaa0111dd'
"$pkgname.service")
md5sums=('2bb2868cf51acbb90c35763c9f995f31'
'SKIP'
'50c392d3668ee9c69281f05f55430d0f'
'2c8cbedb2fb455cba220ca35186ad846'
'23a13ee4c118cb40b086bdb23d25eac2'
'9b6b3791a1da9433e1779aa5155fdc4a')
'23a13ee4c118cb40b086bdb23d25eac2')
prepare() {
cd $pkgname-$pkgver
......
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