From: Florian Weimer Date: Thu, 31 Jan 2019 17:49:58 +0000 (+0100) Subject: nss_files: Fix /etc/aliases null pointer dereference [BZ #24059] X-Git-Tag: upstream/2.30~415 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2bac7daa58da1a313bd452369b0508b31e146637;p=external%2Fglibc.git nss_files: Fix /etc/aliases null pointer dereference [BZ #24059] If /etc/aliases ends with a continuation line (a line that starts with whitespace) which does not have a trailing newline character, the file parser would crash due to a null pointer dereference. Reviewed-by: Carlos O'Donell --- diff --git a/ChangeLog b/ChangeLog index 32579d7..05e13e6 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,19 @@ +2019-01-31 Florian Weimer + + [BZ #24059] + * nss/nss_files/files-alias.c (get_next_alias): Handle + continuation line without newline at the end. + * nss/tst-nss-files-alias-truncated.c: New file. + * nss/Makefile [$(build-shared)] (tests): Add + tst-nss-files-alias-truncated. + (tst-nss-files-alias-truncated): Link with libnss_files.so. + * support/namespace.h (struct support_chroot_configuration): Add + aliases member. + (struct support_chroot): Add path_aliases member. + * support/support_chroot.c (support_chroot_create): Handle + aliases. + (support_chroot_free): Free path_aliases. + 2019-01-31 Siddhesh Poyarekar * version.h (RELEASE): Set to "development". diff --git a/nss/Makefile b/nss/Makefile index 0fa28f0..e66e01d 100644 --- a/nss/Makefile +++ b/nss/Makefile @@ -68,6 +68,7 @@ tests += tst-nss-files-hosts-erange tests += tst-nss-files-hosts-multi tests += tst-nss-files-hosts-getent tests += tst-nss-files-alias-leak +tests += tst-nss-files-alias-truncated endif # If we have a thread library then we can test cancellation against @@ -176,3 +177,4 @@ $(objpfx)tst-nss-files-hosts-multi: $(libdl) $(objpfx)tst-nss-files-hosts-getent: $(libdl) $(objpfx)tst-nss-files-alias-leak: $(libdl) $(objpfx)tst-nss-files-alias-leak.out: $(objpfx)/libnss_files.so +$(objpfx)tst-nss-files-alias-truncated: $(objpfx)/libnss_files.so diff --git a/nss/nss_files/files-alias.c b/nss/nss_files/files-alias.c index 540eb9c..34d7aa8 100644 --- a/nss/nss_files/files-alias.c +++ b/nss/nss_files/files-alias.c @@ -333,6 +333,16 @@ get_next_alias (FILE *stream, const char *match, struct aliasent *result, can be ignored. */ first_unused[room_left - 1] = '\xff'; line = fgets_unlocked (first_unused, room_left, stream); + if (line == NULL) + { + /* Continuation line without any data and + without a newline at the end. Treat it as an + empty line and retry, reaching EOF once + more. */ + line = first_unused; + *line = '\0'; + continue; + } if (first_unused[room_left - 1] != '\xff') goto no_more_room; cp = strpbrk (line, "#\n"); diff --git a/nss/tst-nss-files-alias-truncated.c b/nss/tst-nss-files-alias-truncated.c new file mode 100644 index 0000000..2d6aba3 --- /dev/null +++ b/nss/tst-nss-files-alias-truncated.c @@ -0,0 +1,66 @@ +/* Check handling of missing end-of-line at end of /etc/aliases (bug 24059). + 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 + +static void +in_chroot (void *closure) +{ + struct support_chroot *chroot_env = closure; + xchroot (chroot_env->path_chroot); + + struct aliasent *e = getaliasbyname ("user1"); + TEST_VERIFY_EXIT (e != NULL); + TEST_COMPARE_STRING (e->alias_name, "user1"); + TEST_COMPARE (e->alias_members_len, 1); + TEST_VERIFY_EXIT (e->alias_members != NULL); + TEST_COMPARE_STRING (e->alias_members[0], "alias1"); + TEST_VERIFY (e->alias_local); +} + +static int +do_test (void) +{ + /* nss_files has already been loaded via DT_NEEDED, outside the + chroot. */ + __nss_configure_lookup ("aliases", "files"); + + support_become_root (); + if (!support_can_chroot ()) + return EXIT_UNSUPPORTED; + + struct support_chroot *chroot_env = support_chroot_create + ((struct support_chroot_configuration) + { + .aliases = "user1: alias1,\n" + " " /* Continuation line, but no \n. */ + }); + + support_isolate_in_subprocess (in_chroot, chroot_env); + + support_chroot_free (chroot_env); + return 0; +} + +#include diff --git a/support/namespace.h b/support/namespace.h index f937549..4770cf9 100644 --- a/support/namespace.h +++ b/support/namespace.h @@ -74,6 +74,7 @@ struct support_chroot_configuration const char *resolv_conf; /* /etc/resolv.conf. */ const char *hosts; /* /etc/hosts. */ const char *host_conf; /* /etc/host.conf. */ + const char *aliases; /* /etc/aliases. */ }; /* The result of the creation of a chroot. */ @@ -90,6 +91,7 @@ struct support_chroot char *path_resolv_conf; /* /etc/resolv.conf. */ char *path_hosts; /* /etc/hosts. */ char *path_host_conf; /* /etc/host.conf. */ + char *path_aliases; /* /etc/aliases. */ }; /* Create a chroot environment. The returned data should be freed diff --git a/support/support_chroot.c b/support/support_chroot.c index b866b89..412ec33 100644 --- a/support/support_chroot.c +++ b/support/support_chroot.c @@ -56,6 +56,7 @@ support_chroot_create (struct support_chroot_configuration conf) &chroot->path_resolv_conf); write_file (path_etc, "hosts", conf.hosts, &chroot->path_hosts); write_file (path_etc, "host.conf", conf.host_conf, &chroot->path_host_conf); + write_file (path_etc, "aliases", conf.aliases, &chroot->path_aliases); free (path_etc); @@ -77,5 +78,6 @@ support_chroot_free (struct support_chroot *chroot) free (chroot->path_resolv_conf); free (chroot->path_hosts); free (chroot->path_host_conf); + free (chroot->path_aliases); free (chroot); }