Gitweb:
https://git.exim.org/exim.git/commitdiff/2b615f22d0ce78ba28a6d758d6a2a5c8cb33e10a
Commit: 2b615f22d0ce78ba28a6d758d6a2a5c8cb33e10a
Parent: 0299eb6ae2f923bd2a4ba8f82fc06e615b99c177
Author: Jeremy Harris <jgh146exb@???>
AuthorDate: Wed Jan 1 15:19:52 2020 +0000
Committer: Jeremy Harris <jgh146exb@???>
CommitDate: Wed Jan 1 15:27:41 2020 +0000
GSASL: provide $autnN for scram option expansions
---
doc/doc-docbook/spec.xfpt | 22 +++++++--
doc/doc-txt/ChangeLog | 3 ++
src/src/auths/gsasl_exim.c | 116 ++++++++++++++++++++++-----------------------
test/confs/3820 | 4 +-
4 files changed, 78 insertions(+), 67 deletions(-)
diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 560b720..4d02bdc 100644
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -27544,16 +27544,28 @@ This specifies the SASL realm that the server claims to be in.
Some mechanisms will use this data.
-.option server_scram_iter gsasl string&!! unset
+.option server_scram_iter gsasl string&!! 4096
This option provides data for the SCRAM family of mechanisms.
-&$auth1$& is not available at evaluation time.
-(This may change, as we receive feedback on use)
+.new
+The &$auth1$&, &$auth2$& and &$auth3$& variables are available for expansion.
+
+The result of expansion should be a decimal number,
+and represents both a lower-bound on the security, and
+a compute cost factor imposed on the client
+(if it does not cache results, or the server changes
+either the iteration count or the salt).
+A minimum value of 4096 is required by the standards
+for all current CRAM mechanism variants.
+.wen
.option server_scram_salt gsasl string&!! unset
This option provides data for the SCRAM family of mechanisms.
-&$auth1$& is not available at evaluation time.
-(This may change, as we receive feedback on use)
+.new
+The &$auth1$&, &$auth2$& and &$auth3$& variables are available for expansion.
+If unset or empty after expansion the library will provides a value for the
+protocol conversation.
+.wen
.option server_service gsasl string &`smtp`&
diff --git a/doc/doc-txt/ChangeLog b/doc/doc-txt/ChangeLog
index 491ff52..e1e1e3b 100644
--- a/doc/doc-txt/ChangeLog
+++ b/doc/doc-txt/ChangeLog
@@ -74,6 +74,9 @@ JH/17 Logging: when the deliver_time selector ise set, include the DT= field
on delivery deferred (==) and failed (**) lines (if a delivery was
attemtped). Previously it was only on completion (=>) lines.
+JH/18 Authentication: the gsasl driver not provides the $authN variables in time
+ for the expansion of the server_scram_iter and server_scram_salt options.
+
Exim version 4.93
-----------------
diff --git a/src/src/auths/gsasl_exim.c b/src/src/auths/gsasl_exim.c
index d1640f1..80ae354 100644
--- a/src/src/auths/gsasl_exim.c
+++ b/src/src/auths/gsasl_exim.c
@@ -500,6 +500,36 @@ switch (exim_rc)
return GSASL_AUTHENTICATION_ERROR;
}
+
+static void
+set_exim_authvar_from_prop(Gsasl_session * sctx, Gsasl_property prop)
+{
+uschar * propval = US gsasl_property_fast(sctx, prop);
+int i = expand_nmax, j = i + 1;
+propval = propval ? string_copy(propval) : US"";
+auth_vars[i] = expand_nstring[j] = propval;
+expand_nlength[j] = Ustrlen(propval);
+expand_nmax = j;
+}
+
+static void
+set_exim_authvars_from_a_az_r_props(Gsasl_session * sctx)
+{
+if (expand_nmax > 0 ) return;
+
+/* Asking for GSASL_AUTHZID calls back into us if we use
+gsasl_property_get(), thus the use of gsasl_property_fast().
+Do we really want to hardcode limits per mechanism? What happens when
+a new mechanism is added to the library. It *shouldn't* result in us
+needing to add more glue, since avoiding that is a large part of the
+point of SASL. */
+
+set_exim_authvar_from_prop(sctx, GSASL_AUTHID);
+set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
+set_exim_authvar_from_prop(sctx, GSASL_REALM);
+}
+
+
static int
server_callback(Gsasl *ctx, Gsasl_session *sctx, Gsasl_property prop,
auth_instance *ablock)
@@ -522,15 +552,9 @@ switch (prop)
case GSASL_VALIDATE_SIMPLE:
HDEBUG(D_auth) debug_printf(" VALIDATE_SIMPLE\n");
/* GSASL_AUTHID, GSASL_AUTHZID, and GSASL_PASSWORD */
- propval = US gsasl_property_fast(sctx, GSASL_AUTHID);
- auth_vars[0] = expand_nstring[1] = propval ? string_copy(propval) : US"";
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
- auth_vars[1] = expand_nstring[2] = propval ? string_copy(propval) : US"";
- propval = US gsasl_property_fast(sctx, GSASL_PASSWORD);
- auth_vars[2] = expand_nstring[3] = propval ? string_copy(propval) : US"";
- expand_nmax = 3;
- for (int i = 1; i <= 3; ++i)
- expand_nlength[i] = Ustrlen(expand_nstring[i]);
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHID);
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
+ set_exim_authvar_from_prop(sctx, GSASL_PASSWORD);
cbrc = condition_check(ablock, US"server_condition", ablock->server_condition);
checked_server_condition = TRUE;
@@ -544,12 +568,7 @@ switch (prop)
cbrc = GSASL_AUTHENTICATION_ERROR;
break;
}
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
-
- /* We always set $auth1, even if only to empty string. */
- auth_vars[0] = expand_nstring[1] = propval ? string_copy(propval) : US"";
- expand_nlength[1] = Ustrlen(expand_nstring[1]);
- expand_nmax = 1;
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
cbrc = condition_check(ablock,
US"server_condition (EXTERNAL)", ablock->server_condition);
@@ -564,13 +583,7 @@ switch (prop)
cbrc = GSASL_AUTHENTICATION_ERROR;
break;
}
- propval = US gsasl_property_fast(sctx, GSASL_ANONYMOUS_TOKEN);
-
- /* We always set $auth1, even if only to empty string. */
-
- auth_vars[0] = expand_nstring[1] = propval ? string_copy(propval) : US"";
- expand_nlength[1] = Ustrlen(expand_nstring[1]);
- expand_nmax = 1;
+ set_exim_authvar_from_prop(sctx, GSASL_ANONYMOUS_TOKEN);
cbrc = condition_check(ablock,
US"server_condition (ANONYMOUS)", ablock->server_condition);
@@ -588,13 +601,8 @@ switch (prop)
to the first release of Exim with this authenticator, they've been
switched to match the ordering of GSASL_VALIDATE_SIMPLE. */
- propval = US gsasl_property_fast(sctx, GSASL_GSSAPI_DISPLAY_NAME);
- auth_vars[0] = expand_nstring[1] = propval ? string_copy(propval) : US"";
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
- auth_vars[1] = expand_nstring[2] = propval ? string_copy(propval) : US"";
- expand_nmax = 2;
- for (int i = 1; i <= 2; ++i)
- expand_nlength[i] = Ustrlen(expand_nstring[i]);
+ set_exim_authvar_from_prop(sctx, GSASL_GSSAPI_DISPLAY_NAME);
+ set_exim_authvar_from_prop(sctx, GSASL_AUTHZID);
/* In this one case, it perhaps makes sense to default back open?
But for consistency, let's just mandate server_condition here too. */
@@ -608,66 +616,54 @@ switch (prop)
HDEBUG(D_auth) debug_printf(" SCRAM_ITER\n");
if (ob->server_scram_iter)
{
+ set_exim_authvars_from_a_az_r_props(sctx);
tmps = CS expand_string(ob->server_scram_iter);
+ HDEBUG(D_auth) debug_printf(" '%s'\n", tmps);
gsasl_property_set(sctx, GSASL_SCRAM_ITER, tmps);
cbrc = GSASL_OK;
}
+ else
+ HDEBUG(D_auth) debug_printf(" option not set\n");
break;
case GSASL_SCRAM_SALT:
HDEBUG(D_auth) debug_printf(" SCRAM_SALT\n");
- if (ob->server_scram_iter)
+ if (ob->server_scram_salt)
{
+ set_exim_authvars_from_a_az_r_props(sctx);
tmps = CS expand_string(ob->server_scram_salt);
- gsasl_property_set(sctx, GSASL_SCRAM_SALT, tmps);
+ HDEBUG(D_auth) debug_printf(" '%s'\n", tmps);
+ if (*tmps)
+ gsasl_property_set(sctx, GSASL_SCRAM_SALT, tmps);
cbrc = GSASL_OK;
}
+ else
+ HDEBUG(D_auth) debug_printf(" option not set\n");
break;
case GSASL_PASSWORD:
HDEBUG(D_auth) debug_printf(" PASSWORD\n");
- /* DIGEST-MD5: GSASL_AUTHID, GSASL_AUTHZID and GSASL_REALM
+ /* SCRAM-SHA-1: GSASL_AUTHID, GSASL_AUTHZID and GSASL_REALM
+ DIGEST-MD5: GSASL_AUTHID, GSASL_AUTHZID and GSASL_REALM
CRAM-MD5: GSASL_AUTHID
PLAIN: GSASL_AUTHID and GSASL_AUTHZID
LOGIN: GSASL_AUTHID
*/
- if (ob->server_scram_iter)
- {
- tmps = CS expand_string(ob->server_scram_iter);
- gsasl_property_set(sctx, GSASL_SCRAM_ITER, tmps);
- }
- if (ob->server_scram_salt)
- {
- tmps = CS expand_string(ob->server_scram_salt);
- gsasl_property_set(sctx, GSASL_SCRAM_SALT, tmps);
- }
-
- /* Asking for GSASL_AUTHZID calls back into us if we use
- gsasl_property_get(), thus the use of gsasl_property_fast().
- Do we really want to hardcode limits per mechanism? What happens when
- a new mechanism is added to the library. It *shouldn't* result in us
- needing to add more glue, since avoiding that is a large part of the
- point of SASL. */
-
- propval = US gsasl_property_fast(sctx, GSASL_AUTHID);
- auth_vars[0] = expand_nstring[1] = propval ? string_copy(propval) : US"";
- propval = US gsasl_property_fast(sctx, GSASL_AUTHZID);
- auth_vars[1] = expand_nstring[2] = propval ? string_copy(propval) : US"";
- propval = US gsasl_property_fast(sctx, GSASL_REALM);
- auth_vars[2] = expand_nstring[3] = propval ? string_copy(propval) : US"";
- expand_nmax = 3;
- for (int i = 1; i <= 3; ++i)
- expand_nlength[i] = Ustrlen(expand_nstring[i]);
+ set_exim_authvars_from_a_az_r_props(sctx);
if (!ob->server_password)
+ {
+ HDEBUG(D_auth) debug_printf("option not set\n");
break;
+ }
if (!(tmps = CS expand_string(ob->server_password)))
{
- sasl_error_should_defer = f.expand_string_forcedfail ? FALSE : TRUE;
+ sasl_error_should_defer = !f.expand_string_forcedfail;
HDEBUG(D_auth) debug_printf("server_password expansion failed, so "
"can't tell GNU SASL library the password for %s\n", auth_vars[0]);
return GSASL_AUTHENTICATION_ERROR;
}
+ HDEBUG(D_auth) debug_printf(" set\n");
gsasl_property_set(sctx, GSASL_PASSWORD, tmps);
/* This is inadequate; don't think Exim's store stacks are geared
diff --git a/test/confs/3820 b/test/confs/3820
index b60e467..c80d4d4 100644
--- a/test/confs/3820
+++ b/test/confs/3820
@@ -77,8 +77,8 @@ sasl3:
# a GSASL_SCRAM_SALTED_PASSWORD - but that is only documented for client mode.
# unclear if the salt is given in binary or base64 to the library
- server_scram_salt = QSXCR+Q6sek8bf92
- server_password = pencil
+ server_scram_salt = ${if eq {$auth1}{ph10} {QSXCR+Q6sek8bf92}}
+ server_password = ${if eq {$auth1}{ph10} {pencil}{unset_password}}
server_condition = true
server_set_id = $auth1
