oss-sec mailing list archives
Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability)
From: christos () zoulas com (Christos Zoulas)
Date: Fri, 26 Sep 2014 10:13:22 -0400
On Sep 26, 1:47pm, john.haxby () oracle com (John Haxby) wrote: -- Subject: Re: [oss-security] Re: CVE-2014-6271: remote code execution throu | It's not so much the known attacks -- redefining ls, unset, command, | typeset, declare, etc -- it's the future parser bugs that we don't yet | know about. | | A friend of mine said this could be a vulnerability gift that keeps on | giving. I think that at this point the conservative approach is best, so until the bash author figures what the best solution is, the feature is disabled by default for NetBSD. It is not wise to expose bash's parser to the internet and then debug it live while being attacked. christos $NetBSD: patch-shell.c,v 1.1 2014/09/25 20:28:32 christos Exp $ Add flag to disable importing of function unless explicitly enabled --- shell.c.christos 2014-01-14 08:04:32.000000000 -0500 +++ shell.c 2014-09-25 16:11:51.000000000 -0400 @@ -229,6 +229,7 @@ #else int posixly_correct = 0; /* Non-zero means posix.2 superset. */ #endif +int import_functions = 0; /* Import functions from environment */ /* Some long-winded argument names. These are obviously new. */ #define Int 1 @@ -248,6 +249,7 @@ { "help", Int, &want_initial_help, (char **)0x0 }, { "init-file", Charp, (int *)0x0, &bashrc_file }, { "login", Int, &make_login_shell, (char **)0x0 }, + { "import-functions", Int, &import_functions, (char **)0x0 }, { "noediting", Int, &no_line_editing, (char **)0x0 }, { "noprofile", Int, &no_profile, (char **)0x0 }, { "norc", Int, &no_rc, (char **)0x0 }, $NetBSD: patch-variables.c,v 1.1 2014/09/25 20:28:32 christos Exp $ Only read functions from environment if flag is set. --- variables.c.christos 2014-09-25 16:09:41.000000000 -0400 +++ variables.c 2014-09-25 16:12:10.000000000 -0400 @@ -105,6 +105,7 @@ extern int assigning_in_environment; extern int executing_builtin; extern int funcnest_max; +extern int import_functions; #if defined (READLINE) extern int no_line_editing; @@ -349,7 +350,7 @@ /* If exported function, define it now. Don't import functions from the environment in privileged mode. */ - if (privmode == 0 && read_but_dont_execute == 0 && STREQN ("() {", string, 4)) + if (import_functions && privmode == 0 && read_but_dont_execute == 0 && STREQN ("() {", string, 4)) { string_length = strlen (string); temp_string = (char *)xmalloc (3 + string_length + char_index);
Current thread:
- Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Mark R Bannister (Sep 26)
- <Possible follow-ups>
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Hanno Böck (Sep 26)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Florian Weimer (Sep 26)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) John Haxby (Sep 26)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Bernhard Hermann (Sep 26)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Christos Zoulas (Sep 26)
- Re: Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Bryan Drewery (Sep 26)
- Re: Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Bryan Drewery (Sep 28)
- Re: Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Loganaden Velvindron (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Giles Coochey (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Michal Zalewski (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Michal Zalewski (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Osmond Sun (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Chet Ramey (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Kobrin, Eric (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) Chet Ramey (Sep 29)
- Re: Re: CVE-2014-6271: remote code execution through bash (3rd vulnerability) John Haxby (Sep 26)