From 198256e2184897300e1cea4343437c3b7b6f74ad Mon Sep 17 00:00:00 2001 From: Joseph Sutton Date: Wed, 18 May 2022 16:06:31 +1200 Subject: CVE-2022-2031 gensec_krb5: Add helper function to check if client sent an initial ticket This will be used in the kpasswd service to ensure that the client has an initial ticket to kadmin/changepw, and not a service ticket. BUG: https://bugzilla.samba.org/show_bug.cgi?id=15047 BUG: https://bugzilla.samba.org/show_bug.cgi?id=15049 Signed-off-by: Joseph Sutton Reviewed-by: Andreas Schneider --- source4/auth/gensec/gensec_krb5.c | 20 +-------- source4/auth/gensec/gensec_krb5_helpers.c | 72 ++++++++++++++++++++++++++++++ source4/auth/gensec/gensec_krb5_helpers.h | 32 +++++++++++++ source4/auth/gensec/gensec_krb5_internal.h | 47 +++++++++++++++++++ source4/auth/gensec/wscript_build | 4 ++ 5 files changed, 157 insertions(+), 18 deletions(-) create mode 100644 source4/auth/gensec/gensec_krb5_helpers.c create mode 100644 source4/auth/gensec/gensec_krb5_helpers.h create mode 100644 source4/auth/gensec/gensec_krb5_internal.h diff --git a/source4/auth/gensec/gensec_krb5.c b/source4/auth/gensec/gensec_krb5.c index 7d87b3ac6b9..104e4639c44 100644 --- a/source4/auth/gensec/gensec_krb5.c +++ b/source4/auth/gensec/gensec_krb5.c @@ -44,27 +44,11 @@ #include "../lib/util/asn1.h" #include "auth/kerberos/pac_utils.h" #include "gensec_krb5.h" +#include "gensec_krb5_internal.h" +#include "gensec_krb5_helpers.h" _PUBLIC_ NTSTATUS gensec_krb5_init(TALLOC_CTX *); -enum GENSEC_KRB5_STATE { - GENSEC_KRB5_SERVER_START, - GENSEC_KRB5_CLIENT_START, - GENSEC_KRB5_CLIENT_MUTUAL_AUTH, - GENSEC_KRB5_DONE -}; - -struct gensec_krb5_state { - enum GENSEC_KRB5_STATE state_position; - struct smb_krb5_context *smb_krb5_context; - krb5_auth_context auth_context; - krb5_data enc_ticket; - krb5_keyblock *keyblock; - krb5_ticket *ticket; - bool gssapi; - krb5_flags ap_req_options; -}; - static int gensec_krb5_destroy(struct gensec_krb5_state *gensec_krb5_state) { if (!gensec_krb5_state->smb_krb5_context) { diff --git a/source4/auth/gensec/gensec_krb5_helpers.c b/source4/auth/gensec/gensec_krb5_helpers.c new file mode 100644 index 00000000000..21f2f1e884e --- /dev/null +++ b/source4/auth/gensec/gensec_krb5_helpers.c @@ -0,0 +1,72 @@ +/* + Unix SMB/CIFS implementation. + + Kerberos backend for GENSEC + + Copyright (C) Andrew Bartlett 2004 + Copyright (C) Andrew Tridgell 2001 + Copyright (C) Luke Howard 2002-2003 + Copyright (C) Stefan Metzmacher 2004-2005 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include "includes.h" +#include "auth/auth.h" +#include "auth/gensec/gensec.h" +#include "auth/gensec/gensec_internal.h" +#include "gensec_krb5_internal.h" +#include "gensec_krb5_helpers.h" +#include "system/kerberos.h" +#include "auth/kerberos/kerberos.h" + +static struct gensec_krb5_state *get_private_state(const struct gensec_security *gensec_security) +{ + struct gensec_krb5_state *gensec_krb5_state = NULL; + + if (strcmp(gensec_security->ops->name, "krb5") != 0) { + /* We require that the krb5 mechanism is being used. */ + return NULL; + } + + gensec_krb5_state = talloc_get_type(gensec_security->private_data, + struct gensec_krb5_state); + return gensec_krb5_state; +} + +/* + * Returns 1 if our ticket has the initial flag set, 0 if not, and -1 in case of + * error. + */ +int gensec_krb5_initial_ticket(const struct gensec_security *gensec_security) +{ + struct gensec_krb5_state *gensec_krb5_state = NULL; + + gensec_krb5_state = get_private_state(gensec_security); + if (gensec_krb5_state == NULL) { + return -1; + } + + if (gensec_krb5_state->ticket == NULL) { + /* We don't have a ticket */ + return -1; + } + +#ifdef SAMBA4_USES_HEIMDAL + return gensec_krb5_state->ticket->ticket.flags.initial; +#else /* MIT KERBEROS */ + return (gensec_krb5_state->ticket->enc_part2->flags & TKT_FLG_INITIAL) ? 1 : 0; +#endif /* SAMBA4_USES_HEIMDAL */ +} diff --git a/source4/auth/gensec/gensec_krb5_helpers.h b/source4/auth/gensec/gensec_krb5_helpers.h new file mode 100644 index 00000000000..d7b694dad0c --- /dev/null +++ b/source4/auth/gensec/gensec_krb5_helpers.h @@ -0,0 +1,32 @@ +/* + Unix SMB/CIFS implementation. + + Kerberos backend for GENSEC + + Copyright (C) Andrew Bartlett 2004 + Copyright (C) Andrew Tridgell 2001 + Copyright (C) Luke Howard 2002-2003 + Copyright (C) Stefan Metzmacher 2004-2005 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +struct gensec_security; + +/* + * Returns 1 if our ticket has the initial flag set, 0 if not, and -1 in case of + * error. + */ +int gensec_krb5_initial_ticket(const struct gensec_security *gensec_security); diff --git a/source4/auth/gensec/gensec_krb5_internal.h b/source4/auth/gensec/gensec_krb5_internal.h new file mode 100644 index 00000000000..0bb796f1b2a --- /dev/null +++ b/source4/auth/gensec/gensec_krb5_internal.h @@ -0,0 +1,47 @@ +/* + Unix SMB/CIFS implementation. + + Kerberos backend for GENSEC + + Copyright (C) Andrew Bartlett 2004 + Copyright (C) Andrew Tridgell 2001 + Copyright (C) Luke Howard 2002-2003 + Copyright (C) Stefan Metzmacher 2004-2005 + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program 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 General Public License for more details. + + + You should have received a copy of the GNU General Public License + along with this program. If not, see . +*/ + +#include "includes.h" +#include "auth/gensec/gensec.h" +#include "system/kerberos.h" +#include "auth/kerberos/kerberos.h" + +enum GENSEC_KRB5_STATE { + GENSEC_KRB5_SERVER_START, + GENSEC_KRB5_CLIENT_START, + GENSEC_KRB5_CLIENT_MUTUAL_AUTH, + GENSEC_KRB5_DONE +}; + +struct gensec_krb5_state { + enum GENSEC_KRB5_STATE state_position; + struct smb_krb5_context *smb_krb5_context; + krb5_auth_context auth_context; + krb5_data enc_ticket; + krb5_keyblock *keyblock; + krb5_ticket *ticket; + bool gssapi; + krb5_flags ap_req_options; +}; diff --git a/source4/auth/gensec/wscript_build b/source4/auth/gensec/wscript_build index d14a50ff273..20271f1665b 100644 --- a/source4/auth/gensec/wscript_build +++ b/source4/auth/gensec/wscript_build @@ -18,6 +18,10 @@ bld.SAMBA_MODULE('gensec_krb5', enabled=bld.AD_DC_BUILD_IS_ENABLED() ) +bld.SAMBA_SUBSYSTEM('gensec_krb5_helpers', + source='gensec_krb5_helpers.c', + deps='gensec_krb5', + enabled=bld.AD_DC_BUILD_IS_ENABLED()) bld.SAMBA_MODULE('gensec_gssapi', source='gensec_gssapi.c', -- cgit v1.2.1