OpenBSD安全性建议xlock(1)鉴定

/ns/ld/unix/data/20010303061811.htm

发布日期：2000-12-22
类别：xlock(1)鉴定
摘要:
这是预防性的建议. xlock(1)的鉴定配置改变为通过早期交叉的进程管道进行验证.
虽然在目前使用的xlock(1)鉴定配置中还没有已知的漏洞, 但是相信新的配置加入了更多的安全性
并提供了可用的补丁.

解决方案:
OpenBSD的基础系统并不包括xlock(1). 如果你安装了OpenBSD的X11数据包，
你应该对你的OpenBSD 2.8 X11源目录使用下面的补丁. 该补丁也可以在http://www.openbsd.org/errata.html (014)找到.
或者, 你可以从上面相同的地址中下载新的xlock(1)程序: http://www.openbsd.org/errata.html (014).

涉及:
安全及勘误表,

http://www.openbsd.org/security.html
http://www.openbsd.org/errata.html

OPENBSD 2.8补丁:
执行:
cd /usr/X11
patch -p0<014_xlock.patch

Then rebuild the xlock binary:
cd xc/programs/xlockmore
xmkmf; make Makefiles; make; make install

--- xc/programs/xlockmore/iconfig.h 2000/10/07 17:36:06 1.12
+++ xc/programs/xlockmore/iconfig.h 2000/12/19 20:21:41 1.13
@@ -313,6 +313,10 @@

XCOMM *** END DEBUG CHECK SECTION ***

+XCOMM *** DEFINE THIS TO USE A SEPARATE PROCESS (SAFER) ***
+XCOMM *** TO VALIDATE PASSWORDS ***
+PIPEDEF = -DUSE_A_DAMN_PIPE
+
#ifndef __QNX__
#ifndef MathLibrary
#define MathLibrary -lm
@@ -522,7 +526,7 @@
XCOMM OPTDEF += -DSTAFF_NETGROUP=\"/etc/xlock.netgroup\"

DEFINES = -DDEF_FILESEARCHPATH=\"$(LIBDIR)/%T/%N%S\" \
-$(SYSTEMDEF) $(EDITRESDEF) $(SLEEPDEF) $(OPTDEF) $(RANDDEF) \
+$(PIPEDEF) $(SYSTEMDEF) $(EDITRESDEF) $(SLEEPDEF) $(OPTDEF) $(RANDDEF) \
$(MODULEDEF) $(CHECKDEF) $(UNSTABLEDEF) $(PASSWDDEF) $(XMINC) $(XAWINC) \
$(CPPDEF) $(XPMDEF) $(GLDEF) $(DTSAVERDEF) $(DPMSDEF) \
$(SOUNDDEF) $(PASSWDINC) $(XPMINC) $(GLINC) $(DTSAVERINC) $(DPMSINC) \
--- xc/programs/xlockmore/modes/Imakefile 2000/04/15 09:45:59 1.6
+++ xc/programs/xlockmore/modes/Imakefile 2000/12/19 19:20:23 1.7
@@ -80,7 +80,7 @@
$(DOU)util$(OU)logout$(OU)mode$(OU)ras$(OU)xbm$(O)$(S)\
$(DOU)vis$(OU)color$(OU)random$(OU)iostuff$(OU)automata$(O)$(S)\
$(DOU)spline$(OU)erase$(OU)sound$(O)$(S)\
-$(DOU)vtlock$(OU)vtlock_proc$(O)
+$(DOU)vtlock$(OU)vtlock_proc$(OU)atomicio$(O)
#ifdef Check
XLOCKCHECKOBJS = $(S)memcheck$(O)
#endif
@@ -162,7 +162,7 @@
XLOCKUTILSRCS = $(DU)xlock$(CU)passwd$(CU)resource$(CU)parsecmd$(C) \
$(DU)vis$(CU)color$(CU)random$(CU)iostuff$(CU)automata$(C) \
$(DU)spline$(CU)sound$(CU)erase$(C) \
-$(DU)vtlock$(CU)vtlock_proc$(C)
+$(DU)vtlock$(CU)vtlock_proc$(CU)atomicio$(C)
XLOCKCHECKSRCS = $(DU)memcheck$(C)
XLOCKMODESRCS = $(DM)ant$(CM)ball$(CM)bat$(CM)blot$(C) \
$(DM)bouboule$(CM)bounce$(CM)braid$(CM)bubble$(CM)bug$(C) \
--- xc/programs/xlockmore/xlock/Imakefile 1999/12/05 16:37:06 1.5
+++ xc/programs/xlockmore/xlock/Imakefile 2000/12/19 19:20:24 1.6
@@ -19,7 +19,7 @@
$(DOU)util$(OU)logout$(OU)mode$(OU)ras$(OU)xbm$(O)$(S)\
$(DOU)vis$(OU)color$(OU)random$(OU)iostuff$(OU)automata$(O)$(S)\
$(DOU)spline$(OU)sound$(OU)erase$(O)$(S)\
-$(DOU)vtlock$(OU)vtlock_proc$(O)
+$(DOU)vtlock$(OU)vtlock_proc$(OU)atomicio$(O)
#ifdef Check
XLOCKCHECKOBJS = $(S)memcheck$(O)
#endif
@@ -30,7 +30,7 @@
$(DU)util$(CU)logout$(CU)mode$(CU)ras$(CU)xbm$(C) \
$(DU)vis$(CU)color$(CU)random$(CU)iostuff$(CU)automata$(C) \
$(DU)spline$(CU)sound$(CU)erase$(C) \
-$(DU)vtlock$(CU)vtlock_proc$(C)
+$(DU)vtlock$(CU)vtlock_proc$(CU)atomicio$(C)
XLOCKCHECKSRCS = $(DU)memcheck$(C)

XCOMM default target
--- xc/programs/xlockmore/xlock/passwd.c 2000/04/15 09:46:00 1.9
+++ xc/programs/xlockmore/xlock/passwd.c 2000/12/19 19:20:24 1.10
@@ -64,7 +64,14 @@
#include <sys/param.h>
#endif

+#ifdef USE_A_DAMN_PIPE
+#include <limits.h>

+int passwd_rpipe = -1;
+int passwd_wpipe = -1;
+pid_t passwd_pid;
+#endif
+
#if defined( __bsdi__ ) && _BSDI_VERSION >= 199608
#define BSD_AUTH
#endif
@@ -1193,6 +1200,9 @@
}
}
#endif
+#ifdef USE_A_DAMN_PIPE
+ done = passwd_do_check(buffer);
+#else
if (!done) {
done = (!strcmp((char *) crypt(buffer, userpass), userpass));
/* userpass is used */
@@ -1220,6 +1230,7 @@
syslog(SYSLOG_NOTICE, "%s: %s unlocked screen", ProgramName, ROOT);
#endif
}
+#endif /* !USE_A_DAMN_PIPE */
#endif /* !BSD_AUTH */
#endif /* !ultrix */
#endif /* !PAM */
@@ -1925,9 +1936,50 @@
else
gpass();
#else
+#ifdef USE_A_DAMN_PIPE
+ {
+ int pipes1[2];
+ int pipes2[2];
+
+ if (pipe(pipes1) == -1)
+ return;
+ if (pipe(pipes2) == -1) {
+ close(pipes1[0]);
+ close(pipes1[1]);
+ return;
+ }
+ passwd_pid = fork();
+ switch (passwd_pid) {
+ case -1:
+ close(pipes1[0]);
+ close(pipes1[1]);
+ close(pipes2[0]);
+ close(pipes2[1]);
+ return;
+ default:
+ /* parent */
+ close(pipes1[0]);
+ passwd_wpipe = pipes1[1];
+ close(pipes2[1]);
+ passwd_rpipe = pipes2[0];
+ return;
+
+ case 0:
+ /* child */
+ close(pipes1[1]);
+ passwd_rpipe = pipes1[0];
+ close(pipes2[0]);
+ passwd_wpipe = pipes2[1];
+
+ passwd_run_checks();
+ _exit(1);
+ }
+ }
+#else
getCryptedUserPasswd();
#endif
#endif
+#endif
if (allowroot)
getCryptedRootPasswd();
#endif /* !BSD_AUTH */
@@ -1937,3 +1989,53 @@
initDCE();
#endif
}
+
+#ifdef USE_A_DAMN_PIPE
+
+int
+passwd_do_check(user)
+ char *user;
+{
+ char buf[PIPE_BUF];
+
+ strlcpy(buf, user, sizeof buf);
+ if (atomicio(write, passwd_wpipe, buf, sizeof buf) != sizeof buf)
+ return 0; /* what to do? */
+ buf[0] = '\0';
+ read(passwd_rpipe, buf, 1);
+ if (buf[0])
+ return 1;
+ else
+ return 0;
+}
+
+passwd_run_checks()
+{
+ char buf[PIPE_BUF];
+ struct passwd *pw = NULL;
+ int off, len;
+ u_char ack;
+
+ while (1) {
+ memset(buf, 0, sizeof buf);
+ ack = 0;
+
+ if (atomicio(read, passwd_rpipe, buf, sizeof buf) != sizeof buf)
+ _exit(1);
+
+ buf[sizeof(buf)-1] = '\0';
+
+ pw = getpwnam(user);
+ if (pw && strcmp(crypt(buf, pw->pw_passwd), pw->pw_passwd) == 0)
+ ack = 1;
+ if (ack == 0) {
+ pw = getpwnam("root");
+ if (pw && strcmp(crypt(buf, pw->pw_passwd),
+ pw->pw_passwd) == 0)
+ ack = 1;
+ }
+ endpwent();
+ (void) write(passwd_wpipe, &ack, 1);
+ }
+}
+#endif
--- xc/programs/xlockmore/xlock/resource.c 2000/05/16 03:33:11 1.2
+++ xc/programs/xlockmore/xlock/resource.c 2000/12/19 19:20:24 1.3
@@ -155,8 +155,8 @@
#ifdef USE_MB
#define DEF_FONTSET DEF_FONT ## ",-*-24-*"
#endif
-#define DEF_BG "White"
-#define DEF_FG "Black"
+#define DEF_BG "Black"
+#define DEF_FG "White"
#ifdef FR
#define DEF_NAME "Nom: "
#define DEF_PASS "Mot de passe: "
--- /dev/null Fri Dec 22 01:30:03 2000
+++ xc/programs/xlockmore/xlock/atomicio.c Tue Dec 19 13:20:24 2000
@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 1999 Theo de Raadt
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/types.h>
+#include <errno.h>
+
+/*
+ * ensure all of data on socket comes through. f==read || f==write
+ */
+ssize_t
+atomicio(f, fd, _s, n)
+ ssize_t (*f) ();
+ int fd;
+ void *_s;
+ size_t n;
+{
+ char *s = _s;
+ ssize_t res, pos = 0;
+
+ while (n > pos) {
+ res = (f) (fd, s + pos, n - pos);
+ switch (res) {
+ case -1:
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ case 0:
+ return (res);
+ default:
+ pos += res;
+ }
+ }
+ return (pos);
+}