From daa0470f287c3849c5090ce47fc71ebfd8d0b219 Mon Sep 17 00:00:00 2001 From: cperciva Date: Fri, 23 Dec 2011 15:00:37 +0000 Subject: [PATCH] Fix a problem whereby a corrupt DNS record can cause named to crash. [11:06] Add an API for alerting internal libc routines to the presence of "unsafe" paths post-chroot, and use it in ftpd. [11:07] Fix a buffer overflow in telnetd. [11:08] Make pam_ssh ignore unpassphrased keys unless the "nullok" option is specified. [11:09] Add sanity checking of service names in pam_start. [11:10] Approved by: so (cperciva) Approved by: re (bz) Security: FreeBSD-SA-11:06.bind Security: FreeBSD-SA-11:07.chroot Security: FreeBSD-SA-11:08.telnetd Security: FreeBSD-SA-11:09.pam_ssh Security: FreeBSD-SA-11:10.pam git-svn-id: svn://svn.freebsd.org/base/releng/8.1@228843 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- UPDATING | 16 +++++ contrib/bind9/bin/named/query.c | 19 +++--- contrib/bind9/lib/dns/rbtdb.c | 7 ++- contrib/openpam/lib/openpam_configure.c | 7 +++ contrib/telnet/libtelnet/encrypt.c | 3 + .../heimdal/appl/telnet/libtelnet/encrypt.c | 3 + include/unistd.h | 1 + lib/libc/Versions.def | 6 +- lib/libc/gen/Makefile.inc | 1 + lib/libc/gen/Symbol.map | 4 ++ lib/libc/gen/libc_dlopen.c | 61 +++++++++++++++++++ lib/libc/include/libc_private.h | 11 ++++ lib/libc/net/nsdispatch.c | 4 +- lib/libpam/modules/pam_ssh/pam_ssh.c | 25 +++++--- libexec/ftpd/ftpd.c | 1 + libexec/ftpd/popen.c | 3 + sys/conf/newvers.sh | 2 +- 17 files changed, 150 insertions(+), 24 deletions(-) create mode 100644 lib/libc/gen/libc_dlopen.c diff --git a/UPDATING b/UPDATING index 4d8504f1..3ade2628 100644 --- a/UPDATING +++ b/UPDATING @@ -15,6 +15,22 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 8.x IS SLOW ON IA64 OR SUN4V: debugging tools present in HEAD were left in place because sun4v support still needs work to become production ready. +20111223: p7 FreeBSD-SA-11:06.bind, FreeBSD-SA-11:07.chroot + FreeBSD-SA-11:08.telnetd, FreeBSD-SA-11:09.pam_ssh + FreeBSD-SA-11:10.pam + Fix a problem whereby a corrupt DNS record can cause named to crash. + [11:06] + + Add an API for alerting internal libc routines to the presence of + "unsafe" paths post-chroot, and use it in ftpd. [11:07] + + Fix a buffer overflow in telnetd. [11:08] + + Make pam_ssh ignore unpassphrased keys unless the "nullok" option is + specified. [11:09] + + Add sanity checking of service names in pam_start. [11:10] + 20111004: p6 FreeBSD-SA-11:05.unix (revised) Fix a bug in UNIX socket handling in the linux emulator which was exposed by the security fix in FreeBSD-SA-11:05.unix. diff --git a/contrib/bind9/bin/named/query.c b/contrib/bind9/bin/named/query.c index cef6d7f7..a5237eb7 100644 --- a/contrib/bind9/bin/named/query.c +++ b/contrib/bind9/bin/named/query.c @@ -1282,11 +1282,9 @@ query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) { goto addname; if (result == DNS_R_NCACHENXRRSET) { dns_rdataset_disassociate(rdataset); - /* - * Negative cache entries don't have sigrdatasets. - */ - INSIST(sigrdataset == NULL || - ! dns_rdataset_isassociated(sigrdataset)); + if (sigrdataset != NULL && + dns_rdataset_isassociated(sigrdataset)) + dns_rdataset_disassociate(sigrdataset); } if (result == ISC_R_SUCCESS) { mname = NULL; @@ -1327,8 +1325,9 @@ query_addadditional(void *arg, dns_name_t *name, dns_rdatatype_t qtype) { goto addname; if (result == DNS_R_NCACHENXRRSET) { dns_rdataset_disassociate(rdataset); - INSIST(sigrdataset == NULL || - ! dns_rdataset_isassociated(sigrdataset)); + if (sigrdataset != NULL && + dns_rdataset_isassociated(sigrdataset)) + dns_rdataset_disassociate(sigrdataset); } if (result == ISC_R_SUCCESS) { mname = NULL; @@ -1777,10 +1776,8 @@ query_addadditional2(void *arg, dns_name_t *name, dns_rdatatype_t qtype) { goto setcache; if (result == DNS_R_NCACHENXRRSET) { dns_rdataset_disassociate(rdataset); - /* - * Negative cache entries don't have sigrdatasets. - */ - INSIST(! dns_rdataset_isassociated(sigrdataset)); + if (dns_rdataset_isassociated(sigrdataset)) + dns_rdataset_disassociate(sigrdataset); } if (result == ISC_R_SUCCESS) { /* Remember the result as a cache */ diff --git a/contrib/bind9/lib/dns/rbtdb.c b/contrib/bind9/lib/dns/rbtdb.c index df3a5f47..6ac02441 100644 --- a/contrib/bind9/lib/dns/rbtdb.c +++ b/contrib/bind9/lib/dns/rbtdb.c @@ -278,6 +278,7 @@ typedef ISC_LIST(dns_rbtnode_t) rbtnodelist_t; #define RDATASET_ATTR_RESIGN 0x0020 #define RDATASET_ATTR_STATCOUNT 0x0040 #define RDATASET_ATTR_OPTOUT 0x0080 +#define RDATASET_ATTR_NEGATIVE 0x0100 typedef struct acache_cbarg { dns_rdatasetadditional_t type; @@ -316,6 +317,8 @@ struct acachectl { (((header)->attributes & RDATASET_ATTR_RESIGN) != 0) #define OPTOUT(header) \ (((header)->attributes & RDATASET_ATTR_OPTOUT) != 0) +#define NEGATIVE(header) \ + (((header)->attributes & RDATASET_ATTR_NEGATIVE) != 0) #define DEFAULT_NODE_LOCK_COUNT 7 /*%< Should be prime. */ @@ -4618,7 +4621,7 @@ cache_find(dns_db_t *db, dns_name_t *name, dns_dbversion_t *version, rdataset); if (need_headerupdate(found, search.now)) update = found; - if (foundsig != NULL) { + if (!NEGATIVE(found) && foundsig != NULL) { bind_rdataset(search.rbtdb, node, foundsig, search.now, sigrdataset); if (need_headerupdate(foundsig, search.now)) @@ -5245,7 +5248,7 @@ cache_findrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version, } if (found != NULL) { bind_rdataset(rbtdb, rbtnode, found, now, rdataset); - if (foundsig != NULL) + if (!NEGATIVE(found) && foundsig != NULL) bind_rdataset(rbtdb, rbtnode, foundsig, now, sigrdataset); } diff --git a/contrib/openpam/lib/openpam_configure.c b/contrib/openpam/lib/openpam_configure.c index f9197adc..688b2acc 100644 --- a/contrib/openpam/lib/openpam_configure.c +++ b/contrib/openpam/lib/openpam_configure.c @@ -285,6 +285,13 @@ openpam_load_chain(pam_handle_t *pamh, size_t len; int r; + /* don't allow to escape from policy_path */ + if (strchr(service, '/')) { + openpam_log(PAM_LOG_ERROR, "invalid service name: %s", + service); + return (-PAM_SYSTEM_ERR); + } + for (path = openpam_policy_path; *path != NULL; ++path) { len = strlen(*path); if ((*path)[len - 1] == '/') { diff --git a/contrib/telnet/libtelnet/encrypt.c b/contrib/telnet/libtelnet/encrypt.c index 8bdf672a..f8e91941 100644 --- a/contrib/telnet/libtelnet/encrypt.c +++ b/contrib/telnet/libtelnet/encrypt.c @@ -721,6 +721,9 @@ encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len) int dir = kp->dir; int ret = 0; + if (len > MAXKEYLEN) + len = MAXKEYLEN; + if (!(ep = (*kp->getcrypt)(*kp->modep))) { if (len == 0) return; diff --git a/crypto/heimdal/appl/telnet/libtelnet/encrypt.c b/crypto/heimdal/appl/telnet/libtelnet/encrypt.c index 04dbe83d..a4669d23 100644 --- a/crypto/heimdal/appl/telnet/libtelnet/encrypt.c +++ b/crypto/heimdal/appl/telnet/libtelnet/encrypt.c @@ -736,6 +736,9 @@ encrypt_keyid(struct key_info *kp, unsigned char *keyid, int len) int dir = kp->dir; int ret = 0; + if (len > MAXKEYLEN) + len = MAXKEYLEN; + if (!(ep = (*kp->getcrypt)(*kp->modep))) { if (len == 0) return; diff --git a/include/unistd.h b/include/unistd.h index b4b7516b..4782380a 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -513,6 +513,7 @@ int initgroups(const char *, gid_t); int iruserok(unsigned long, int, const char *, const char *); int iruserok_sa(const void *, int, int, const char *, const char *); int issetugid(void); +void __FreeBSD_libc_enter_restricted_mode(void); long lpathconf(const char *, int); #ifndef _MKDTEMP_DECLARED char *mkdtemp(char *); diff --git a/lib/libc/Versions.def b/lib/libc/Versions.def index da0ca6f8..bbd59a4e 100644 --- a/lib/libc/Versions.def +++ b/lib/libc/Versions.def @@ -19,6 +19,10 @@ FBSD_1.1 { FBSD_1.2 { } FBSD_1.1; +# This version was first added to 10.0-current. +FBSD_1.3 { +} FBSD_1.2; + # This is our private namespace. Any global interfaces that are # strictly for use only by other FreeBSD applications and libraries # are listed here. We use a separate namespace so we can write @@ -26,4 +30,4 @@ FBSD_1.2 { # # Please do NOT increment the version of this namespace. FBSDprivate_1.0 { -} FBSD_1.2; +} FBSD_1.3; diff --git a/lib/libc/gen/Makefile.inc b/lib/libc/gen/Makefile.inc index d04dd750..ed61bd58 100644 --- a/lib/libc/gen/Makefile.inc +++ b/lib/libc/gen/Makefile.inc @@ -20,6 +20,7 @@ SRCS+= __getosreldate.c __xuname.c \ getpeereid.c getprogname.c getpwent.c getttyent.c \ getusershell.c getvfsbyname.c glob.c \ initgroups.c isatty.c isinf.c isnan.c jrand48.c lcong48.c \ + libc_dlopen.c \ lockf.c lrand48.c mrand48.c nftw.c nice.c \ nlist.c nrand48.c opendir.c \ pause.c pmadvise.c popen.c posix_spawn.c \ diff --git a/lib/libc/gen/Symbol.map b/lib/libc/gen/Symbol.map index 4c19a3de..03edd607 100644 --- a/lib/libc/gen/Symbol.map +++ b/lib/libc/gen/Symbol.map @@ -369,6 +369,10 @@ FBSD_1.2 { getpagesizes; }; +FBSD_1.3 { + __FreeBSD_libc_enter_restricted_mode; +}; + FBSDprivate_1.0 { /* needed by thread libraries */ __thr_jtable; diff --git a/lib/libc/gen/libc_dlopen.c b/lib/libc/gen/libc_dlopen.c new file mode 100644 index 00000000..2b1aa9e9 --- /dev/null +++ b/lib/libc/gen/libc_dlopen.c @@ -0,0 +1,61 @@ +/*- + * Copyright (c) 2011 Xin Li + * 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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. + * + * $FreeBSD$ + */ + +#include +__FBSDID("$FreeBSD$"); + +#include +#include +#include + +#include "libc_private.h" + +/* + * Whether we want to restrict dlopen()s. + */ +static int __libc_restricted_mode = 0; + +void * +libc_dlopen(const char *path, int mode) +{ + + if (__libc_restricted_mode) { + _rtld_error("Service unavailable -- libc in restricted mode"); + return (NULL); + } else + return (dlopen(path, mode)); +} + +void +__FreeBSD_libc_enter_restricted_mode(void) +{ + + __libc_restricted_mode = 1; + return; +} + diff --git a/lib/libc/include/libc_private.h b/lib/libc/include/libc_private.h index 052eb130..d5f4212f 100644 --- a/lib/libc/include/libc_private.h +++ b/lib/libc/include/libc_private.h @@ -43,6 +43,17 @@ */ extern int __isthreaded; +/* + * libc should use libc_dlopen internally, which respects a global + * flag where loading of new shared objects can be restricted. + */ +void *libc_dlopen(const char *, int); + +/* + * For dynamic linker. + */ +void _rtld_error(const char *fmt, ...); + /* * File lock contention is difficult to diagnose without knowing * where locks were set. Allow a debug library to be built which diff --git a/lib/libc/net/nsdispatch.c b/lib/libc/net/nsdispatch.c index 162d592a..08a0d183 100644 --- a/lib/libc/net/nsdispatch.c +++ b/lib/libc/net/nsdispatch.c @@ -384,7 +384,7 @@ nss_configure(void) confmod = statbuf.st_mtime; #ifdef NS_CACHING - handle = dlopen(NULL, RTLD_LAZY | RTLD_GLOBAL); + handle = libc_dlopen(NULL, RTLD_LAZY | RTLD_GLOBAL); if (handle != NULL) { nss_cache_cycle_prevention_func = dlsym(handle, "_nss_cache_cycle_prevention_function"); @@ -497,7 +497,7 @@ nss_load_module(const char *source, nss_module_register_fn reg_fn) if (snprintf(buf, sizeof(buf), "nss_%s.so.%d", mod.name, NSS_MODULE_INTERFACE_VERSION) >= (int)sizeof(buf)) goto fin; - mod.handle = dlopen(buf, RTLD_LOCAL|RTLD_LAZY); + mod.handle = libc_dlopen(buf, RTLD_LOCAL|RTLD_LAZY); if (mod.handle == NULL) { #ifdef _NSS_DEBUG /* This gets pretty annoying since the built-in diff --git a/lib/libpam/modules/pam_ssh/pam_ssh.c b/lib/libpam/modules/pam_ssh/pam_ssh.c index 9d89045a..4eeabe18 100644 --- a/lib/libpam/modules/pam_ssh/pam_ssh.c +++ b/lib/libpam/modules/pam_ssh/pam_ssh.c @@ -91,7 +91,8 @@ static char *const pam_ssh_agent_envp[] = { NULL }; * struct pam_ssh_key containing the key and its comment. */ static struct pam_ssh_key * -pam_ssh_load_key(const char *dir, const char *kfn, const char *passphrase) +pam_ssh_load_key(const char *dir, const char *kfn, const char *passphrase, + int nullok) { struct pam_ssh_key *psk; char fn[PATH_MAX]; @@ -101,7 +102,21 @@ pam_ssh_load_key(const char *dir, const char *kfn, const char *passphrase) if (snprintf(fn, sizeof(fn), "%s/%s", dir, kfn) > (int)sizeof(fn)) return (NULL); comment = NULL; - key = key_load_private(fn, passphrase, &comment); + /* + * If the key is unencrypted, OpenSSL ignores the passphrase, so + * it will seem like the user typed in the right one. This allows + * a user to circumvent nullok by providing a dummy passphrase. + * Verify that the key really *is* encrypted by trying to load it + * with an empty passphrase, and if the key is not encrypted, + * accept only an empty passphrase. + */ + key = key_load_private(fn, NULL, &comment); + if (key != NULL && !(*passphrase == '\0' && nullok)) { + key_free(key); + return (NULL); + } + if (key == NULL) + key = key_load_private(fn, passphrase, &comment); if (key == NULL) { openpam_log(PAM_LOG_DEBUG, "failed to load key from %s\n", fn); return (NULL); @@ -168,9 +183,6 @@ pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, if (pam_err != PAM_SUCCESS) return (pam_err); - if (*passphrase == '\0' && !nullok) - goto skip_keys; - /* switch to user credentials */ pam_err = openpam_borrow_cred(pamh, pwd); if (pam_err != PAM_SUCCESS) @@ -178,7 +190,7 @@ pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, /* try to load keys from all keyfiles we know of */ for (kfn = pam_ssh_keyfiles; *kfn != NULL; ++kfn) { - psk = pam_ssh_load_key(pwd->pw_dir, *kfn, passphrase); + psk = pam_ssh_load_key(pwd->pw_dir, *kfn, passphrase, nullok); if (psk != NULL) { pam_set_data(pamh, *kfn, psk, pam_ssh_free_key); ++nkeys; @@ -188,7 +200,6 @@ pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, /* switch back to arbitrator credentials */ openpam_restore_cred(pamh); - skip_keys: /* * If we tried an old token and didn't get anything, and * try_first_pass was specified, try again after prompting the diff --git a/libexec/ftpd/ftpd.c b/libexec/ftpd/ftpd.c index 32c15f8d..64485168 100644 --- a/libexec/ftpd/ftpd.c +++ b/libexec/ftpd/ftpd.c @@ -1543,6 +1543,7 @@ skip: reply(550, "Can't change root."); goto bad; } + __FreeBSD_libc_enter_restricted_mode(); } else /* real user w/o chroot */ homedir = pw->pw_dir; /* diff --git a/libexec/ftpd/popen.c b/libexec/ftpd/popen.c index 8a739dc2..9f80507a 100644 --- a/libexec/ftpd/popen.c +++ b/libexec/ftpd/popen.c @@ -143,6 +143,9 @@ ftpd_popen(char *program, char *type) } (void)close(pdes[1]); } + /* Drop privileges before proceeding */ + if (getuid() != geteuid() && setuid(geteuid()) < 0) + _exit(1); if (strcmp(gargv[0], _PATH_LS) == 0) { /* Reset getopt for ls_main() */ optreset = optind = optopt = 1; diff --git a/sys/conf/newvers.sh b/sys/conf/newvers.sh index fc406f69..2ddb0b98 100644 --- a/sys/conf/newvers.sh +++ b/sys/conf/newvers.sh @@ -32,7 +32,7 @@ TYPE="FreeBSD" REVISION="8.1" -BRANCH="RELEASE-p6" +BRANCH="RELEASE-p7" if [ "X${BRANCH_OVERRIDE}" != "X" ]; then BRANCH=${BRANCH_OVERRIDE} fi -- 2.42.0