From 51721282ae021e57888b38720a4acd69e88a8f4f Mon Sep 17 00:00:00 2001

From: Robbie Harwood <rharwood@redhat.com>

Date: Mon, 20 Nov 2017 14:09:04 -0500

Subject: [PATCH] Properly locate credentials in collection caches in mechglue

Previously, we would just put the credentials in the default cache for

a collection type, which lead to some mysterious failures.

Signed-off-by: Robbie Harwood <rharwood@redhat.com>

Reviewed-by: Simo Sorce <simo@redhat.com>

Merges: #221

(cherry picked from commit 670240a6cd4d5e2ecf13e481621098693cdbaa89)

---

 proxy/src/mechglue/gpp_creds.c  | 81 +++++++++++++++++++++++++++++------------

 proxy/src/mechglue/gss_plugin.h |  2 +-

 2 files changed, 59 insertions(+), 24 deletions(-)

diff --git a/proxy/src/mechglue/gpp_creds.c b/proxy/src/mechglue/gpp_creds.c

index 3ebd726..187ada7 100644

--- a/proxy/src/mechglue/gpp_creds.c

+++ b/proxy/src/mechglue/gpp_creds.c

@@ -170,7 +170,16 @@ static krb5_error_code gpp_construct_cred(gssx_cred *creds, krb5_context ctx,

     return 0;

 }

-uint32_t gpp_store_remote_creds(uint32_t *min, bool default_creds,

+/* Store creds from remote in a local ccache, updating where possible.

+ *

+ * If store_as_default_cred is true, the cred is made default for its

+ * collection, if there is one.  Note that if the ccache is not of a

+ * collection type, the creds will overwrite the ccache.

+ *

+ * If no "ccache" entry is specified in cred_store, the default ccache for a

+ * new context will be used.

+ */

+uint32_t gpp_store_remote_creds(uint32_t *min, bool store_as_default_cred,

                                 gss_const_key_value_set_t cred_store,

                                 gssx_cred *creds)

 {

@@ -179,7 +188,7 @@ uint32_t gpp_store_remote_creds(uint32_t *min, bool default_creds,

     krb5_creds cred;

     krb5_error_code ret;

     char cred_name[creds->desired_name.display_name.octet_string_len + 1];

-    const char *cc_type;

+    const char *cc_name;

     *min = 0;

@@ -191,38 +200,64 @@ uint32_t gpp_store_remote_creds(uint32_t *min, bool default_creds,

         goto done;

     }

-    if (cred_store) {

-        for (unsigned i = 0; i < cred_store->count; i++) {

-            if (strcmp(cred_store->elements[i].key, "ccache") == 0) {

-                ret = krb5_cc_resolve(ctx, cred_store->elements[i].value,

-                                      &ccache);

-                if (ret) goto done;

-                break;

-            }

+    for (unsigned i = 0; cred_store && i < cred_store->count; i++) {

+        if (strcmp(cred_store->elements[i].key, "ccache") == 0) {

+            /* krb5 creates new ccaches based off the default name. */

+            ret = krb5_cc_set_default_name(ctx,

+                                           cred_store->elements[i].value);

+            if (ret)

+                goto done;

+

+            break;

         }

     }

-    if (!ccache) {

-        if (!default_creds) {

-            ret = ENOMEDIUM;

-            goto done;

-        }

-        ret = krb5_cc_default(ctx, &ccache);

-        if (ret) goto done;

-    }

-    cc_type = krb5_cc_get_type(ctx, ccache);

-    if (strcmp(cc_type, "FILE") == 0) {

+    cc_name = krb5_cc_default_name(ctx);

+    if (strncmp(cc_name, "FILE:", 5) == 0 || !strchr(cc_name, ':')) {

         /* FILE ccaches don't handle updates properly: if they have the same

          * principal name, they are blackholed.  We either have to change the

          * name (at which point the file grows forever) or flash the cache on

          * every update. */

-        ret = krb5_cc_initialize(ctx, ccache, cred.client);

-        if (ret != 0) {

+        ret = krb5_cc_default(ctx, &ccache);

+        if (ret)

             goto done;

-        }

+

+        ret = krb5_cc_initialize(ctx, ccache, cred.client);

+        if (ret != 0)

+            goto done;

+

+        ret = krb5_cc_store_cred(ctx, ccache, &cred);

+        goto done;

     }

+    ret = krb5_cc_cache_match(ctx, cred.client, &ccache);

+    if (ret == KRB5_CC_NOTFOUND) {

+        /* A new ccache within the collection whose name is based off the

+         * default_name for the context.  krb5_cc_new_unique only accepts the

+         * leading component of a name as a type. */

+        char *cc_type;

+        const char *p;

+

+        p = strchr(cc_name, ':'); /* can't be FILE here */

+        cc_type = strndup(cc_name, p - cc_name);

+        if (!cc_type) {

+            ret = ENOMEM;

+            goto done;

+        }

+

+        ret = krb5_cc_new_unique(ctx, cc_type, NULL, &ccache);

+        free(cc_type);

+    }

+    if (ret)

+        goto done;

+

     ret = krb5_cc_store_cred(ctx, ccache, &cred);

+    if (ret)

+        goto done;

+

+    if (store_as_default_cred) {

+        ret = krb5_cc_switch(ctx, ccache);

+    }

 done:

     if (ctx) {

diff --git a/proxy/src/mechglue/gss_plugin.h b/proxy/src/mechglue/gss_plugin.h

index 333d63c..c0e8870 100644

--- a/proxy/src/mechglue/gss_plugin.h

+++ b/proxy/src/mechglue/gss_plugin.h

@@ -76,7 +76,7 @@ uint32_t gpp_cred_handle_init(uint32_t *min, bool defcred, const char *ccache,

                               struct gpp_cred_handle **out_handle);

 uint32_t gpp_cred_handle_free(uint32_t *min, struct gpp_cred_handle *handle);

 bool gpp_creds_are_equal(gssx_cred *a, gssx_cred *b);

-uint32_t gpp_store_remote_creds(uint32_t *min, bool default_creds,

+uint32_t gpp_store_remote_creds(uint32_t *min, bool store_as_default_cred,

                                 gss_const_key_value_set_t cred_store,

                                 gssx_cred *creds);