From: Lennart Poettering <lennart@poettering.net>
Date: Wed, 22 Jan 2020 16:52:10 +0100
Subject: polkit: on async pk requests, re-validate action/details

When we do an async pk request, let's store which action/details we used
for the original request, and when we are called for the second time,
let's compare. If the action/details changed, let's not allow the access
to go through.

(cherry picked from commit 7f56982289275ce84e20f0554475864953e6aaab)
(cherry picked from commit 0697d0d972c8d91395eb539a8e87e4aec8b37b75)
(cherry picked from commit 54791aff01aa93a8b621808d80ab506b54f245c8)
(cherry picked from commit 70d0f5ea5952a0cedd84c352070613df4ba5fc8f)
---
 src/shared/bus-polkit.c | 30 +++++++++++++++++++++++++++---
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/src/shared/bus-polkit.c b/src/shared/bus-polkit.c
index 81193b8..6343dd6 100644
--- a/src/shared/bus-polkit.c
+++ b/src/shared/bus-polkit.c
@@ -155,6 +155,9 @@ int bus_test_polkit(
 #if ENABLE_POLKIT
 
 typedef struct AsyncPolkitQuery {
+        char *action;
+        char **details;
+
         sd_bus_message *request, *reply;
         sd_bus_message_handler_t callback;
         void *userdata;
@@ -175,6 +178,9 @@ static void async_polkit_query_free(AsyncPolkitQuery *q) {
         sd_bus_message_unref(q->request);
         sd_bus_message_unref(q->reply);
 
+        free(q->action);
+        strv_free(q->details);
+
         free(q);
 }
 
@@ -239,11 +245,17 @@ int bus_verify_polkit_async(
         if (q) {
                 int authorized, challenge;
 
-                /* This is the second invocation of this function, and
-                 * there's already a response from polkit, let's
-                 * process it */
+                /* This is the second invocation of this function, and there's already a response from
+                 * polkit, let's process it */
                 assert(q->reply);
 
+                /* If the operation we want to authenticate changed between the first and the second time,
+                 * let's not use this authentication, it might be out of date as the object and context we
+                 * operate on might have changed. */
+                if (!streq(q->action, action) ||
+                    !strv_equal(q->details, (char**) details))
+                        return -ESTALE;
+
                 if (sd_bus_message_is_method_error(q->reply, NULL)) {
                         const sd_bus_error *e;
 
@@ -339,6 +351,18 @@ int bus_verify_polkit_async(
         q->callback = callback;
         q->userdata = userdata;
 
+        q->action = strdup(action);
+        if (!q->action) {
+                async_polkit_query_free(q);
+                return -ENOMEM;
+        }
+
+        q->details = strv_copy((char**) details);
+        if (!q->details) {
+                async_polkit_query_free(q);
+                return -ENOMEM;
+        }
+
         r = hashmap_put(*registry, call, q);
         if (r < 0) {
                 async_polkit_query_free(q);