Date: Thu, 10 Dec 1998 22:56:24 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: "Jordan K. Hubbard" <jkh@zippy.cdrom.com> Cc: Archie Cobbs <archie@whistle.com>, jwd@unx.sas.com (John W. DeBoskey), freebsd-current@FreeBSD.ORG Subject: Re: inetd: realloc/free bug Message-ID: <199812110656.WAA35034@apollo.backplane.com> References: <3244.913357673@zippy.cdrom.com>
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I think we can get this fixed pretty quickly, there really isn't much to
it. A couple of minor race conditions in select() as Archie pointed out,
but there is so little left that can go wrong I expect we'll cover all
our bases in short order.
My current proposed diff is included below. This is off the top of my
head and barely tested (yet), but ...
-Matt
:
:> Ick. character flags through a pipe? Ick. Ick. Let me fix this
:> thing, guys, I'm getting tired of all the arguing and non-action for
:> such a simple bug.
:
:You won't get any argument from me. :-)
:
:- Jordan
:
Matthew Dillon Engineering, HiWay Technologies, Inc. & BEST Internet
Communications & God knows what else.
<dillon@backplane.com> (Please include original email in any response)
Index: inetd.c
===================================================================
RCS file: /home/ncvs/src/usr.sbin/inetd/inetd.c,v
retrieving revision 1.41
diff -c -r1.41 inetd.c
*** inetd.c 1998/11/04 19:39:46 1.41
--- inetd.c 1998/12/11 06:54:48
***************
*** 431,449 ****
(void)setenv("inetd_dummy", dummy, 1);
}
for (;;) {
int n, ctrl;
fd_set readable;
if (nsock == 0) {
- (void) sigblock(SIGBLOCK);
while (nsock == 0)
sigpause(0L);
- (void) sigsetmask(0L);
}
readable = allsock;
! if ((n = select(maxsock + 1, &readable, (fd_set *)0,
! (fd_set *)0, (struct timeval *)0)) <= 0) {
if (n < 0 && errno != EINTR) {
syslog(LOG_WARNING, "select: %m");
sleep(1);
--- 431,467 ----
(void)setenv("inetd_dummy", dummy, 1);
}
+ (void) sigblock(SIGBLOCK);
+
for (;;) {
int n, ctrl;
fd_set readable;
+ struct timeval tv = { 5, 0 };
+
+
+ /*
+ * Handle signal masking and select. Signals are unmasked and
+ * we pause if we have no active descriptors. If we do have
+ * active descriptors, leave signals unmasked through the select()
+ * call.
+ *
+ * Signals are masked at all other times.
+ */
if (nsock == 0) {
while (nsock == 0)
sigpause(0L);
}
+
+ (void) sigsetmask(0L);
+
+
readable = allsock;
! n = select(maxsock + 1, &readable, NULL, NULL, &tv);
!
! (void) sigblock(SIGBLOCK);
!
! if (n <= 0) {
if (n < 0 && errno != EINTR) {
syslog(LOG_WARNING, "select: %m");
sleep(1);
***************
*** 490,496 ****
}
} else
ctrl = sep->se_fd;
! (void) sigblock(SIGBLOCK);
pid = 0;
dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
if (dofork) {
--- 508,514 ----
}
} else
ctrl = sep->se_fd;
! /* (void) sigblock(SIGBLOCK); */
pid = 0;
dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
if (dofork) {
***************
*** 509,515 ****
"%s/%s server failing (looping), service terminated",
sep->se_service, sep->se_proto);
close_sep(sep);
! sigsetmask(0L);
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
--- 527,533 ----
"%s/%s server failing (looping), service terminated",
sep->se_service, sep->se_proto);
close_sep(sep);
! /* sigsetmask(0L); */
if (!timingout) {
timingout = 1;
alarm(RETRYTIME);
***************
*** 524,536 ****
if (sep->se_accept &&
sep->se_socktype == SOCK_STREAM)
close(ctrl);
! sigsetmask(0L);
sleep(1);
continue;
}
if (pid)
addchild(sep, pid);
! sigsetmask(0L);
if (pid == 0) {
if (dofork) {
if (debug)
--- 542,554 ----
if (sep->se_accept &&
sep->se_socktype == SOCK_STREAM)
close(ctrl);
! /* sigsetmask(0L); */
sleep(1);
continue;
}
if (pid)
addchild(sep, pid);
! /* sigsetmask(0L); */
if (pid == 0) {
if (dofork) {
if (debug)
***************
*** 713,719 ****
int signo;
{
struct servtab *sep, *new, **sepp;
! long omask;
if (!setconfig()) {
syslog(LOG_ERR, "%s: %m", CONFIG);
--- 731,737 ----
int signo;
{
struct servtab *sep, *new, **sepp;
! /* long omask; */
if (!setconfig()) {
syslog(LOG_ERR, "%s: %m", CONFIG);
***************
*** 751,757 ****
int i;
#define SWAP(a, b) { typeof(a) c = a; a = b; b = c; }
! omask = sigblock(SIGBLOCK);
/* copy over outstanding child pids */
if (sep->se_maxchild && new->se_maxchild) {
new->se_numchild = sep->se_numchild;
--- 769,775 ----
int i;
#define SWAP(a, b) { typeof(a) c = a; a = b; b = c; }
! /* omask = sigblock(SIGBLOCK); */
/* copy over outstanding child pids */
if (sep->se_maxchild && new->se_maxchild) {
new->se_numchild = sep->se_numchild;
***************
*** 784,790 ****
SWAP(sep->se_server, new->se_server);
for (i = 0; i < MAXARGV; i++)
SWAP(sep->se_argv[i], new->se_argv[i]);
! sigsetmask(omask);
freeconfig(new);
if (debug)
print_service("REDO", sep);
--- 802,808 ----
SWAP(sep->se_server, new->se_server);
for (i = 0; i < MAXARGV; i++)
SWAP(sep->se_argv[i], new->se_argv[i]);
! /* sigsetmask(omask); */
freeconfig(new);
if (debug)
print_service("REDO", sep);
***************
*** 839,845 ****
/*
* Purge anything not looked at above.
*/
! omask = sigblock(SIGBLOCK);
sepp = &servtab;
while ((sep = *sepp)) {
if (sep->se_checked) {
--- 857,863 ----
/*
* Purge anything not looked at above.
*/
! /* omask = sigblock(SIGBLOCK); */
sepp = &servtab;
while ((sep = *sepp)) {
if (sep->se_checked) {
***************
*** 856,862 ****
freeconfig(sep);
free((char *)sep);
}
! (void) sigsetmask(omask);
}
void
--- 874,880 ----
freeconfig(sep);
free((char *)sep);
}
! /* (void) sigsetmask(omask); */
}
void
***************
*** 865,873 ****
{
int i;
struct servtab *sepp;
! long omask;
! omask = sigblock(SIGBLOCK);
for (sepp = servtab; sepp; sepp = sepp->se_next) {
if (sepp == sep)
continue;
--- 883,891 ----
{
int i;
struct servtab *sepp;
! /* long omask; */
! /* omask = sigblock(SIGBLOCK); */
for (sepp = servtab; sepp; sepp = sepp->se_next) {
if (sepp == sep)
continue;
***************
*** 884,890 ****
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
! (void) sigsetmask(omask);
}
void
--- 902,908 ----
if (sep->se_fd != -1)
(void) close(sep->se_fd);
sep->se_fd = -1;
! /* (void) sigsetmask(omask); */
}
void
***************
*** 997,1003 ****
struct servtab *cp;
{
struct servtab *sep;
! long omask;
sep = (struct servtab *)malloc(sizeof (*sep));
if (sep == (struct servtab *)0) {
--- 1015,1021 ----
struct servtab *cp;
{
struct servtab *sep;
! /* long omask; */
sep = (struct servtab *)malloc(sizeof (*sep));
if (sep == (struct servtab *)0) {
***************
*** 1006,1015 ****
}
*sep = *cp;
sep->se_fd = -1;
! omask = sigblock(SIGBLOCK);
sep->se_next = servtab;
servtab = sep;
! sigsetmask(omask);
return (sep);
}
--- 1024,1033 ----
}
*sep = *cp;
sep->se_fd = -1;
! /* omask = sigblock(SIGBLOCK); */
sep->se_next = servtab;
servtab = sep;
! /* sigsetmask(omask); */
return (sep);
}
***************
*** 1783,1788 ****
--- 1801,1809 ----
/*
* Based on TCPMUX.C by Mark K. Lottor November 1988
* sri-nic::ps:<mkl>tcpmux.c
+ *
+ * signals are masked on call, we have to unmask SIGALRM for the
+ * duration of the read.
*/
***************
*** 1794,1812 ****
{
int count = 0, n;
struct sigaction sa;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_DFL;
sigaction(SIGALRM, &sa, (struct sigaction *)0);
do {
alarm(10);
n = read(fd, buf, len-count);
alarm(0);
if (n == 0)
! return (count);
! if (n < 0)
! return (-1);
while (--n >= 0) {
if (*buf == '\r' || *buf == '\n' || *buf == '\0')
return (count);
--- 1815,1839 ----
{
int count = 0, n;
struct sigaction sa;
+ long omask;
sa.sa_flags = 0;
sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_DFL;
sigaction(SIGALRM, &sa, (struct sigaction *)0);
+
+ omask = sigsetmask(SIGBLOCK & ~sigmask(SIGALRM));
+
do {
alarm(10);
n = read(fd, buf, len-count);
alarm(0);
if (n == 0)
! break;
! if (n < 0) {
! count = -1;
! break;
! }
while (--n >= 0) {
if (*buf == '\r' || *buf == '\n' || *buf == '\0')
return (count);
***************
*** 1814,1819 ****
--- 1841,1848 ----
buf++;
}
} while (count < len);
+
+ sigsetmask(omask);
return (count);
}
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