From patchwork Tue Jun 18 18:58:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: DJ Delorie X-Patchwork-Id: 33203 Received: (qmail 116385 invoked by alias); 18 Jun 2019 18:58:48 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 116375 invoked by uid 89); 18 Jun 2019 18:58:48 -0000 Authentication-Results: sourceware.org; auth=none X-Spam-SWARE-Status: No, score=-17.4 required=5.0 tests=AWL, BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_SHORT, SPF_HELO_PASS autolearn=ham version=3.3.1 spammy= X-HELO: mx1.redhat.com From: DJ Delorie To: "Carlos O'Donell" Cc: fweimer@redhat.com, schwab@suse.de, libc-alpha@sourceware.org Subject: [PATCH v5] Re: nss_db: protect against empty mappings In-Reply-To: (carlos@redhat.com) Date: Tue, 18 Jun 2019 14:58:38 -0400 Message-ID: MIME-Version: 1.0 "Carlos O'Donell" writes: > OK for master if you: > > - Use expected subject convention "[PATCH v3] ..." > - Fix test comment. > - Add block comments to the tests. > > Reviewed-by: Carlos O'Donell And a v5 to fix some build warnings... From 864952d782df68771590ff85a697504bb3174e8d Mon Sep 17 00:00:00 2001 From: DJ Delorie Date: Mon, 17 Jun 2019 15:33:27 -0400 Subject: nss_db: fix endent wrt NULL mappings [BZ #24695] [BZ #24696] nss_db allows for getpwent et al to be called without a set*ent, but it only works once. After the last get*ent a set*ent is required to restart, because the end*ent did not properly reset the module. Resetting it to NULL allows for a proper restart. If the database doesn't exist, however, end*ent erroniously called munmap which set errno. The test case runs "makedb" inside the testroot, so needs selinux DSOs installed. Reviewed-by: Carlos O'Donell diff --git a/ChangeLog b/ChangeLog index 2f5dac5190..ae49367cdb 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,19 @@ +2019-06-17 DJ Delorie + Sergei Trofimovich + + [BZ #24696] + [BZ #24695] + * nss/nss_db/db-open.c (internal_endent): Protect against NULL + mappings. + * nss/tst-nss-db-endgrent.c: New. + * nss/tst-nss-db-endgrent.root: New. + * nss/tst-nss-db-endpwent.c: New. + * nss/tst-nss-db-endpwent.root: New. + * nss/Makefile: Add new tests. + * support/links-dso-program-c.c: Add selinux dependency. + * support/links-dso-program.cc: Add selinux dependency. + * support/Makefile: Build those with -lselinux if enabled. + 2019-06-17 Adhemerval Zanella * sysdeps/unix/sysv/linux/m68k/Makefile (sysdep_routines, diff --git a/nss/Makefile b/nss/Makefile index 95081bddc5..a15c3b7d90 100644 --- a/nss/Makefile +++ b/nss/Makefile @@ -61,7 +61,9 @@ xtests = bug-erange tests-container = \ tst-nss-test3 \ - tst-nss-files-hosts-long + tst-nss-files-hosts-long \ + tst-nss-db-endpwent \ + tst-nss-db-endgrent # Tests which need libdl ifeq (yes,$(build-shared)) diff --git a/nss/nss_db/db-open.c b/nss/nss_db/db-open.c index 8a83d6b930..3fa11e9ab0 100644 --- a/nss/nss_db/db-open.c +++ b/nss/nss_db/db-open.c @@ -63,5 +63,9 @@ internal_setent (const char *file, struct nss_db_map *mapping) void internal_endent (struct nss_db_map *mapping) { - munmap (mapping->header, mapping->len); + if (mapping->header != NULL) + { + munmap (mapping->header, mapping->len); + mapping->header = NULL; + } } diff --git a/nss/tst-nss-db-endgrent.c b/nss/tst-nss-db-endgrent.c new file mode 100644 index 0000000000..367cc6c901 --- /dev/null +++ b/nss/tst-nss-db-endgrent.c @@ -0,0 +1,54 @@ +/* Test for endgrent changing errno for BZ #24696 + Copyright (C) 2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include + +#include +#include + +/* The following test verifies that if the db NSS Service is initialized + with no database (getgrent), that a subsequent closure (endgrent) does + not set errno. In the case of the db service it is not an error to close + the service and so it should not set errno. */ + +static int +do_test (void) +{ + /* Just make sure it's not there, although usually it won't be. */ + unlink ("/var/db/group.db"); + + /* This, in conjunction with the testroot's nsswitch.conf, causes + the nss_db module to be "connected" and initialized - but the + testroot has no group.db, so no mapping will be created. */ + getgrent (); + + errno = 0; + + /* Before the fix, this would call munmap (NULL) and set errno. */ + endgrent (); + + if (errno != 0) + FAIL_EXIT1 ("endgrent set errno to %d\n", errno); + + return 0; +} +#include diff --git a/nss/tst-nss-db-endgrent.root/etc/nsswitch.conf b/nss/tst-nss-db-endgrent.root/etc/nsswitch.conf new file mode 100644 index 0000000000..21471df94f --- /dev/null +++ b/nss/tst-nss-db-endgrent.root/etc/nsswitch.conf @@ -0,0 +1 @@ +group : db files diff --git a/nss/tst-nss-db-endpwent.c b/nss/tst-nss-db-endpwent.c new file mode 100644 index 0000000000..0a8b3184b0 --- /dev/null +++ b/nss/tst-nss-db-endpwent.c @@ -0,0 +1,70 @@ +/* Test for endpwent->getpwent crash for BZ #24695 + Copyright (C) 2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include + +#include +#include + +/* It is entirely allowed to start with a getpwent call without + resetting the state of the service via a call to setpwent. + You can also call getpwent more times than you have entries in + the service, and it should not fail. This test iteratates the + database once, gets to the end, and then attempts a second + iteration to look for crashes. */ + +static void +try_it (void) +{ + struct passwd *pw; + + /* setpwent is intentionally omitted here. The first call to + getpwent detects that it's first and initializes. The second + time try_it is called, this "first call" was not detected before + the fix, and getpwent would crash. */ + + while ((pw = getpwent ()) != NULL) + ; + + /* We only care if this segfaults or not. */ + endpwent (); +} + +static int +do_test (void) +{ + char *cmd; + const char *rest; + + rest = "/makedb -o /var/db/passwd.db /var/db/passwd.in"; + cmd = (char *) xmalloc (strlen (support_bindir_prefix) + + strlen (rest) + 1); + strcpy (cmd, support_bindir_prefix); + strcat (cmd, rest); + + system (cmd); + + try_it (); + try_it (); + + return 0; +} +#include diff --git a/nss/tst-nss-db-endpwent.root/etc/nsswitch.conf b/nss/tst-nss-db-endpwent.root/etc/nsswitch.conf new file mode 100644 index 0000000000..593ffc564a --- /dev/null +++ b/nss/tst-nss-db-endpwent.root/etc/nsswitch.conf @@ -0,0 +1 @@ +passwd: db diff --git a/nss/tst-nss-db-endpwent.root/var/db/passwd.in b/nss/tst-nss-db-endpwent.root/var/db/passwd.in new file mode 100644 index 0000000000..98f39126ef --- /dev/null +++ b/nss/tst-nss-db-endpwent.root/var/db/passwd.in @@ -0,0 +1,4 @@ +.root root:x:0:0:root:/root:/bin/bash +=0 root:x:0:0:root:/root:/bin/bash +.bin bin:x:1:1:bin:/bin:/sbin/nologin +=1 bin:x:1:1:bin:/bin:/sbin/nologin diff --git a/support/Makefile b/support/Makefile index 56c1ed43bb..ab66913a02 100644 --- a/support/Makefile +++ b/support/Makefile @@ -191,6 +191,11 @@ LINKS_DSO_PROGRAM = links-dso-program LDLIBS-links-dso-program = -lstdc++ -lgcc -lgcc_s $(libunwind) endif +ifeq (yes,$(have-selinux)) +LDLIBS-$(LINKS_DSO_PROGRAM) += -lselinux +endif + + LDLIBS-test-container = $(libsupport) others += test-container diff --git a/support/links-dso-program-c.c b/support/links-dso-program-c.c index d28a28a0d0..e8b64c12ab 100644 --- a/support/links-dso-program-c.c +++ b/support/links-dso-program-c.c @@ -1,9 +1,19 @@ #include +/* makedb needs selinux dso's. */ +#ifdef HAVE_SELINUX +# include +int sel; +#endif + int main (int argc, char **argv) { /* Complexity to keep gcc from optimizing this away. */ printf ("This is a test %s.\n", argc > 1 ? argv[1] : "null"); +#ifdef HAVE_SELINUX + /* We only care about the dependency on selinux, not the result. */ + sel = is_selinux_enabled (); +#endif return 0; } diff --git a/support/links-dso-program.cc b/support/links-dso-program.cc index dba6976c06..87bbc2f46b 100644 --- a/support/links-dso-program.cc +++ b/support/links-dso-program.cc @@ -1,5 +1,11 @@ #include +/* makedb needs selinux dso's. */ +#ifdef HAVE_SELINUX +# include +int sel; +#endif + using namespace std; int @@ -7,5 +13,9 @@ main (int argc, char **argv) { /* Complexity to keep gcc from optimizing this away. */ cout << (argc > 1 ? argv[1] : "null"); +#ifdef HAVE_SELINUX + /* We only care about the dependency on selinux, not the result. */ + sel = is_selinux_enabled (); +#endif return 0; }