From 862b60c249c8a51095315062b22c0702a6500d80 Mon Sep 17 00:00:00 2001
From: Simo Sorce <simo@redhat.com>
Date: Tue, 11 Apr 2017 18:31:46 -0400
Subject: [PATCH 1/3] Drop unused parameter from gssapi_spnego_ssf()
Signed-off-by: Simo Sorce <simo@redhat.com>
---
plugins/gssapi.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/plugins/gssapi.c b/plugins/gssapi.c
index 010c236..3050962 100644
--- a/plugins/gssapi.c
+++ b/plugins/gssapi.c
@@ -652,7 +652,7 @@ static void gssapi_common_mech_free(void *global_context __attribute__((unused))
* flags negotiated by GSSAPI to determine If confidentiality or integrity are
* used. These flags are stored in text->qop transalated as layers by the
* caller */
-static int gssapi_spnego_ssf(context_t *text, const sasl_utils_t *utils,
+static int gssapi_spnego_ssf(context_t *text,
sasl_security_properties_t *props,
sasl_out_params_t *oparams)
{
@@ -1019,7 +1019,7 @@ gssapi_server_mech_authneg(context_t *text,
text->state = SASL_GSSAPI_STATE_AUTHENTICATED;
ret = SASL_OK;
} else if (text->mech_type && text->mech_type == &gss_spnego_oid) {
- ret = gssapi_spnego_ssf(text, params->utils, ¶ms->props, oparams);
+ ret = gssapi_spnego_ssf(text, ¶ms->props, oparams);
} else {
/* Switch to ssf negotiation */
text->state = SASL_GSSAPI_STATE_SSFCAP;
@@ -1825,8 +1825,7 @@ static int gssapi_client_mech_step(void *conn_context,
return SASL_OK;
} else if (text->mech_type && text->mech_type == &gss_spnego_oid) {
oparams->doneflag = 1;
- return gssapi_spnego_ssf(text, params->utils, ¶ms->props,
- oparams);
+ return gssapi_spnego_ssf(text, ¶ms->props, oparams);
}
/* Switch to ssf negotiation */
From 72181257d77bda09afa7d0d640d322c4472f4833 Mon Sep 17 00:00:00 2001
From: Simo Sorce <simo@redhat.com>
Date: Mon, 10 Apr 2017 18:35:10 -0400
Subject: [PATCH 2/3] Check return error from gss_wrap_size_limit()
The return error of this function is ignored and potentially
uninitialized values returned by this function are used.
Fix this by moving the function into a proper helper as it is used in an
identical way in 3 different places.
Signed-off-by: Simo Sorce <simo@redhat.com>
---
plugins/gssapi.c | 104 +++++++++++++++++++++++++++----------------------------
1 file changed, 51 insertions(+), 53 deletions(-)
diff --git a/plugins/gssapi.c b/plugins/gssapi.c
index 3050962..348debe 100644
--- a/plugins/gssapi.c
+++ b/plugins/gssapi.c
@@ -648,6 +648,32 @@ static void gssapi_common_mech_free(void *global_context __attribute__((unused))
#endif
}
+static int gssapi_wrap_sizes(context_t *text, sasl_out_params_t *oparams)
+{
+ OM_uint32 maj_stat = 0, min_stat = 0;
+ OM_uint32 max_input = 0;
+
+ maj_stat = gss_wrap_size_limit(&min_stat,
+ text->gss_ctx,
+ 1,
+ GSS_C_QOP_DEFAULT,
+ (OM_uint32)oparams->maxoutbuf,
+ &max_input);
+ if (maj_stat != GSS_S_COMPLETE) {
+ return SASL_FAIL;
+ }
+
+ if (max_input > oparams->maxoutbuf) {
+ /* Heimdal appears to get this wrong */
+ oparams->maxoutbuf -= (max_input - oparams->maxoutbuf);
+ } else {
+ /* This code is actually correct */
+ oparams->maxoutbuf = max_input;
+ }
+
+ return SASL_OK;
+}
+
/* The GSS-SPNEGO mechanism does not do SSF negotiation, instead it uses the
* flags negotiated by GSSAPI to determine If confidentiality or integrity are
* used. These flags are stored in text->qop transalated as layers by the
@@ -656,8 +682,7 @@ static int gssapi_spnego_ssf(context_t *text,
sasl_security_properties_t *props,
sasl_out_params_t *oparams)
{
- OM_uint32 maj_stat = 0, min_stat = 0;
- OM_uint32 max_input;
+ int ret;
if (text->qop & LAYER_CONFIDENTIALITY) {
oparams->encode = &gssapi_privacy_encode;
@@ -674,20 +699,10 @@ static int gssapi_spnego_ssf(context_t *text,
}
if (oparams->mech_ssf) {
- maj_stat = gss_wrap_size_limit(&min_stat,
- text->gss_ctx,
- 1,
- GSS_C_QOP_DEFAULT,
- (OM_uint32)oparams->maxoutbuf,
- &max_input);
-
- if (max_input > oparams->maxoutbuf) {
- /* Heimdal appears to get this wrong */
- oparams->maxoutbuf -= (max_input - oparams->maxoutbuf);
- } else {
- /* This code is actually correct */
- oparams->maxoutbuf = max_input;
- }
+ ret = gssapi_wrap_sizes(text, oparams);
+ if (ret != SASL_OK) {
+ return ret;
+ }
}
text->state = SASL_GSSAPI_STATE_AUTHENTICATED;
@@ -1208,7 +1223,6 @@ gssapi_server_mech_ssfreq(context_t *text,
gss_buffer_t input_token, output_token;
gss_buffer_desc real_input_token, real_output_token;
OM_uint32 maj_stat = 0, min_stat = 0;
- OM_uint32 max_input;
int layerchoice;
input_token = &real_input_token;
@@ -1297,27 +1311,20 @@ gssapi_server_mech_ssfreq(context_t *text,
(((unsigned char *) output_token->value)[2] << 8) |
(((unsigned char *) output_token->value)[3] << 0);
- if (oparams->mech_ssf) {
- maj_stat = gss_wrap_size_limit( &min_stat,
- text->gss_ctx,
- 1,
- GSS_C_QOP_DEFAULT,
- (OM_uint32) oparams->maxoutbuf,
- &max_input);
-
- if(max_input > oparams->maxoutbuf) {
- /* Heimdal appears to get this wrong */
- oparams->maxoutbuf -= (max_input - oparams->maxoutbuf);
- } else {
- /* This code is actually correct */
- oparams->maxoutbuf = max_input;
- }
- }
-
GSS_LOCK_MUTEX_CTX(params->utils, text);
gss_release_buffer(&min_stat, output_token);
GSS_UNLOCK_MUTEX_CTX(params->utils, text);
+ if (oparams->mech_ssf) {
+ int ret;
+
+ ret = gssapi_wrap_sizes(text, oparams);
+ if (ret != SASL_OK) {
+ sasl_gss_free_context_contents(text);
+ return ret;
+ }
+ }
+
text->state = SASL_GSSAPI_STATE_AUTHENTICATED;
/* used by layers */
@@ -1569,7 +1576,6 @@ static int gssapi_client_mech_step(void *conn_context,
gss_buffer_t input_token, output_token;
gss_buffer_desc real_input_token, real_output_token;
OM_uint32 maj_stat = 0, min_stat = 0;
- OM_uint32 max_input;
gss_buffer_desc name_token;
int ret;
OM_uint32 req_flags = 0, out_req_flags = 0;
@@ -1952,27 +1958,19 @@ static int gssapi_client_mech_step(void *conn_context,
(((unsigned char *) output_token->value)[2] << 8) |
(((unsigned char *) output_token->value)[3] << 0);
- if (oparams->mech_ssf) {
- maj_stat = gss_wrap_size_limit( &min_stat,
- text->gss_ctx,
- 1,
- GSS_C_QOP_DEFAULT,
- (OM_uint32) oparams->maxoutbuf,
- &max_input);
-
- if (max_input > oparams->maxoutbuf) {
- /* Heimdal appears to get this wrong */
- oparams->maxoutbuf -= (max_input - oparams->maxoutbuf);
- } else {
- /* This code is actually correct */
- oparams->maxoutbuf = max_input;
- }
- }
-
GSS_LOCK_MUTEX_CTX(params->utils, text);
gss_release_buffer(&min_stat, output_token);
GSS_UNLOCK_MUTEX_CTX(params->utils, text);
-
+
+ if (oparams->mech_ssf) {
+ int ret;
+
+ ret = gssapi_wrap_sizes(text, oparams);
+ if (ret != SASL_OK) {
+ sasl_gss_free_context_contents(text);
+ return ret;
+ }
+ }
/* oparams->user is always set, due to canon_user requirements.
* Make sure the client actually requested it though, by checking
* if our context was set.
From ff9f9caeb6db6d7513128fff9321f9bd445f58b7 Mon Sep 17 00:00:00 2001
From: Simo Sorce <simo@redhat.com>
Date: Mon, 10 Apr 2017 19:54:19 -0400
Subject: [PATCH 3/3] Add support for retrieving the mech_ssf
In the latest MIT Kerberos implementation it is possible to extract
the calculated SSF wich is based on the encryption type that has been
used to establish the GSSAPI security context.
Use this method if available or fall back to the old "DES" value.
Signed-off-by: Simo Sorce <simo@redhat.com>
---
m4/sasl2.m4 | 20 +++++++++++
plugins/gssapi.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++------
2 files changed, 111 insertions(+), 11 deletions(-)
diff --git a/cmulocal/sasl2.m4 b/cmulocal/sasl2.m4
index 66b291b..686c4bc 100644
--- a/cmulocal/sasl2.m4
+++ b/cmulocal/sasl2.m4
@@ -290,6 +290,26 @@ if test "$gssapi" != no; then
cmu_save_LIBS="$LIBS"
LIBS="$LIBS $GSSAPIBASE_LIBS"
+ AC_CHECK_FUNCS(gss_inquire_sec_context_by_oid)
+ if test "$ac_cv_func_gss_inquire_sec_context_by_oid" = no ; then
+ if test "$ac_cv_header_gssapi_gssapi_ext_h" = "yes"; then
+ AC_CHECK_DECL(gss_inquire_sec_context_by_oid,
+ [AC_DEFINE(HAVE_GSS_INQUIRE_SEC_CONTEXT_BY_OID,1,
+ [Define if your GSSAPI implementation defines gss_inquire_sec_context_by_oid])],,
+ [
+ AC_INCLUDES_DEFAULT
+ #include <gssapi/gssapi_ext.h>
+ ])
+ fi
+ fi
+ if test "$ac_cv_header_gssapi_gssapi_ext_h" = "yes"; then
+ AC_EGREP_HEADER(GSS_C_SEC_CONTEXT_SASL_SSF, gssapi/gssapi_ext.h,
+ [AC_DEFINE(HAVE_GSS_C_SEC_CONTEXT_SASL_SSF,,
+ [Define if your GSSAPI implementation defines GSS_C_SEC_CONTEXT_SASL_SSF])])
+ fi
+ cmu_save_LIBS="$LIBS"
+ LIBS="$LIBS $GSSAPIBASE_LIBS"
+
AC_MSG_CHECKING([for SPNEGO support in GSSAPI libraries])
AC_TRY_RUN([
#ifdef HAVE_GSSAPI_H
diff --git a/plugins/gssapi.c b/plugins/gssapi.c
index 348debe..5f554ce 100644
--- a/plugins/gssapi.c
+++ b/plugins/gssapi.c
@@ -51,7 +51,12 @@
#include <gssapi/gssapi.h>
#endif
+#ifdef HAVE_GSSAPI_GSSAPI_KRB5_H
#include <gssapi/gssapi_krb5.h>
+#endif
+#ifdef HAVE_GSSAPI_GSSAPI_EXT_H
+#include <gssapi/gssapi_ext.h>
+#endif
#ifdef WIN32
# include <winsock2.h>
@@ -98,18 +103,25 @@ extern gss_OID gss_nt_service_name;
/* Check if CyberSafe flag is defined */
#ifdef CSF_GSS_C_DES3_FLAG
#define K5_MAX_SSF 112
+#define K5_MIN_SSF 112
#endif
/* Heimdal and MIT use the following */
#ifdef GSS_KRB5_CONF_C_QOP_DES3_KD
#define K5_MAX_SSF 112
+#define K5_MIN_SSF 112
#endif
#endif
#ifndef K5_MAX_SSF
+/* All modern Kerberos implementations support AES */
+#define K5_MAX_SSF 256
+#endif
+
/* All Kerberos implementations support DES */
-#define K5_MAX_SSF 56
+#ifndef K5_MIN_SSF
+#define K5_MIN_SSF 56
#endif
/* GSSAPI SASL Mechanism by Leif Johansson <leifj@matematik.su.se>
@@ -674,6 +686,47 @@ static int gssapi_wrap_sizes(context_t *text, sasl_out_params_t *oparams)
return SASL_OK;
}
+#if !defined(HAVE_GSS_C_SEC_CONTEXT_SASL_SSF)
+gss_OID_desc gss_sasl_ssf = {
+ 11, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02\x05\x0f"
+};
+gss_OID GSS_C_SEC_CONTEXT_SASL_SSF = &gss_sasl_ssf;
+#endif
+
+static int gssapi_get_ssf(context_t *text, sasl_ssf_t *mech_ssf)
+{
+#ifdef HAVE_GSS_INQUIRE_SEC_CONTEXT_BY_OID
+ OM_uint32 maj_stat = 0, min_stat = 0;
+ gss_buffer_set_t bufset = GSS_C_NO_BUFFER_SET;
+ gss_OID ssf_oid = GSS_C_SEC_CONTEXT_SASL_SSF;
+ uint32_t ssf;
+
+ maj_stat = gss_inquire_sec_context_by_oid(&min_stat, text->gss_ctx,
+ ssf_oid, &bufset);
+ switch (maj_stat) {
+ case GSS_S_UNAVAILABLE:
+ /* Not supported by the library, fallback to default */
+ goto fallback;
+ case GSS_S_COMPLETE:
+ if ((bufset->count != 1) || (bufset->elements[0].length != 4)) {
+ /* Malformed bufset, fail */
+ (void)gss_release_buffer_set(&min_stat, &bufset);
+ return SASL_FAIL;
+ }
+ memcpy(&ssf, bufset->elements[0].value, 4);
+ (void)gss_release_buffer_set(&min_stat, &bufset);
+ *mech_ssf = ntohl(ssf);
+ return SASL_OK;
+ default:
+ return SASL_FAIL;
+ }
+
+fallback:
+#endif
+ *mech_ssf = K5_MIN_SSF;
+ return SASL_OK;
+}
+
/* The GSS-SPNEGO mechanism does not do SSF negotiation, instead it uses the
* flags negotiated by GSSAPI to determine If confidentiality or integrity are
* used. These flags are stored in text->qop transalated as layers by the
@@ -687,7 +740,10 @@ static int gssapi_spnego_ssf(context_t *text,
if (text->qop & LAYER_CONFIDENTIALITY) {
oparams->encode = &gssapi_privacy_encode;
oparams->decode = &gssapi_decode;
- oparams->mech_ssf = K5_MAX_SSF;
+ ret = gssapi_get_ssf(text, &oparams->mech_ssf);
+ if (ret != SASL_OK) {
+ return ret;
+ }
} else if (text->qop & LAYER_INTEGRITY) {
oparams->encode = &gssapi_integrity_encode;
oparams->decode = &gssapi_decode;
@@ -1089,6 +1145,7 @@ gssapi_server_mech_ssfcap(context_t *text,
gss_buffer_desc real_input_token, real_output_token;
OM_uint32 maj_stat = 0, min_stat = 0;
unsigned char sasldata[4];
+ sasl_ssf_t mech_ssf;
int ret;
input_token = &real_input_token;
@@ -1149,9 +1206,14 @@ gssapi_server_mech_ssfcap(context_t *text,
params->props.maxbufsize) {
sasldata[0] |= LAYER_INTEGRITY;
}
+ ret = gssapi_get_ssf(text, &mech_ssf);
+ if (ret != SASL_OK) {
+ sasl_gss_free_context_contents(text);
+ return ret;
+ }
if ((text->qop & LAYER_CONFIDENTIALITY) &&
- text->requiressf <= K5_MAX_SSF &&
- text->limitssf >= K5_MAX_SSF &&
+ text->requiressf <= mech_ssf &&
+ text->limitssf >= mech_ssf &&
params->props.maxbufsize) {
sasldata[0] |= LAYER_CONFIDENTIALITY;
}
@@ -1271,10 +1333,18 @@ gssapi_server_mech_ssfreq(context_t *text,
/* For compatibility with broken clients setting both bits */
layerchoice == (LAYER_CONFIDENTIALITY|LAYER_INTEGRITY)) &&
(text->qop & LAYER_CONFIDENTIALITY)) { /* privacy */
+ int ret;
oparams->encode = &gssapi_privacy_encode;
oparams->decode = &gssapi_decode;
- /* FIX ME: Need to extract the proper value here */
- oparams->mech_ssf = K5_MAX_SSF;
+
+ ret = gssapi_get_ssf(text, &oparams->mech_ssf);
+ if (ret != SASL_OK) {
+ GSS_LOCK_MUTEX_CTX(params->utils, text);
+ gss_release_buffer(&min_stat, output_token);
+ GSS_UNLOCK_MUTEX_CTX(params->utils, text);
+ sasl_gss_free_context_contents(text);
+ return ret;
+ }
} else {
/* not a supported encryption layer */
SETERROR(text->utils,
@@ -1845,6 +1915,8 @@ static int gssapi_client_mech_step(void *conn_context,
unsigned int alen, external = params->external_ssf;
sasl_ssf_t need, allowed;
char serverhas, mychoice;
+ sasl_ssf_t mech_ssf;
+ int ret;
real_input_token.value = (void *) serverin;
real_input_token.length = serverinlen;
@@ -1879,8 +1951,17 @@ static int gssapi_client_mech_step(void *conn_context,
return SASL_FAIL;
}
+ ret = gssapi_get_ssf(text, &mech_ssf);
+ if (ret != SASL_OK) {
+ GSS_LOCK_MUTEX_CTX(params->utils, text);
+ gss_release_buffer(&min_stat, output_token);
+ GSS_UNLOCK_MUTEX_CTX(params->utils, text);
+ sasl_gss_free_context_contents(text);
+ return SASL_FAIL;
+ }
+
/* taken from kerberos.c */
- if (secprops->min_ssf > (K5_MAX_SSF + external)) {
+ if (secprops->min_ssf > (mech_ssf + external)) {
return SASL_TOOWEAK;
} else if (secprops->min_ssf > secprops->max_ssf) {
return SASL_BADPARAM;
@@ -1904,8 +1985,8 @@ static int gssapi_client_mech_step(void *conn_context,
/* use the strongest layer available */
if ((text->qop & LAYER_CONFIDENTIALITY) &&
- allowed >= K5_MAX_SSF &&
- need <= K5_MAX_SSF &&
+ allowed >= mech_ssf &&
+ need <= mech_ssf &&
(serverhas & LAYER_CONFIDENTIALITY)) {
const char *ad_compat;
@@ -1913,8 +1994,7 @@ static int gssapi_client_mech_step(void *conn_context,
/* encryption */
oparams->encode = &gssapi_privacy_encode;
oparams->decode = &gssapi_decode;
- /* FIX ME: Need to extract the proper value here */
- oparams->mech_ssf = K5_MAX_SSF;
+ oparams->mech_ssf = mech_ssf;
mychoice = LAYER_CONFIDENTIALITY;
if (serverhas & LAYER_INTEGRITY) {