From dc3b2a2b22106fa4c0033a5557584f3b08c942e2 Mon Sep 17 00:00:00 2001

From: Marek Blaha <mblaha@redhat.com>

Date: Fri, 3 Jan 2020 12:35:33 +0100

Subject: [PATCH] Remove killGpgAgent function (RhBug:1781601)

Instead ensure that /run/user/$UID directory exists so gpgagent could

create its socket in it.

The solution with KILLAGENT caused race condition with gpgme_release()

call and that resulted in dnf being possibly terminated by SIGPIPE after

importing the first repository gpg key.

https://bugzilla.redhat.com/show_bug.cgi?id=1781601

---

 libdnf/repo/Repo.cpp | 56 +++++++++++++++++++++++---------------------

 1 file changed, 29 insertions(+), 27 deletions(-)

diff --git a/libdnf/repo/Repo.cpp b/libdnf/repo/Repo.cpp

index 850e5b4a8..c1891cce9 100644

--- a/libdnf/repo/Repo.cpp

+++ b/libdnf/repo/Repo.cpp

@@ -846,27 +846,35 @@ std::vector<Key> Repo::Impl::retrieve(const std::string & url)

     return keyInfos;

 }

-static void killGpgAgent(gpgme_ctx_t context, const std::string & gpgDir)

-{

+/*

+ * Creates the '/run/user/$UID' directory if it doesn't exist. If this

+ * directory exists, gpgagent will create its sockets under

+ * '/run/user/$UID/gnupg'.

+ *

+ * If this directory doesn't exist, gpgagent will create its sockets in gpg

+ * home directory, which is under '/var/cache/yum/metadata/' and this was

+ * causing trouble with container images, see [1].

+ *

+ * Previous solution was to send the agent a "KILLAGENT" message, but that

+ * would cause a race condition with calling gpgme_release(), see [2], [3],

+ * [4].

+ *

+ * Since the agent doesn't clean up its sockets properly, by creating this

+ * directory we make sure they are in a place that is not causing trouble with

+ * container images.

+ *

+ * [1] https://bugzilla.redhat.com/show_bug.cgi?id=1650266

+ * [2] https://bugzilla.redhat.com/show_bug.cgi?id=1769831

+ * [3] https://github.com/rpm-software-management/microdnf/issues/50

+ * [4] https://bugzilla.redhat.com/show_bug.cgi?id=1781601

+ */

+static void ensure_socket_dir_exists() {

     auto logger(Log::getLogger());

-

-    auto gpgErr = gpgme_set_protocol(context, GPGME_PROTOCOL_ASSUAN);

-    if (gpgErr != GPG_ERR_NO_ERROR) {

-        auto msg = tfm::format(_("%s: gpgme_set_protocol(): %s"), __func__, gpgme_strerror(gpgErr));

-        logger->warning(msg);

-        return;

-    }

-    std::string gpgAgentSock = gpgDir + "/S.gpg-agent";

-    gpgErr = gpgme_ctx_set_engine_info(context, GPGME_PROTOCOL_ASSUAN, gpgAgentSock.c_str(), gpgDir.c_str());

-    if (gpgErr != GPG_ERR_NO_ERROR) {

-        auto msg = tfm::format(_("%s: gpgme_ctx_set_engine_info(): %s"), __func__, gpgme_strerror(gpgErr));

-        logger->warning(msg);

-        return;

-    }

-    gpgErr = gpgme_op_assuan_transact_ext(context, "KILLAGENT", NULL, NULL, NULL, NULL, NULL, NULL, NULL);

-    if (gpgErr != GPG_ERR_NO_ERROR) {

-        auto msg = tfm::format(_("%s: gpgme_op_assuan_transact_ext(): %s"), __func__, gpgme_strerror(gpgErr));

-        logger->debug(msg);

+    std::string dirname = "/run/user/" + std::to_string(getuid());

+    int res = mkdir(dirname.c_str(), 0700);

+    if (res != 0 && errno != EEXIST) {

+        logger->debug(tfm::format("Failed to create directory \"%s\": %d - %s",

+                                  dirname, errno, strerror(errno)));

     }

 }

@@ -876,6 +884,7 @@ void Repo::Impl::importRepoKeys()

     auto gpgDir = getCachedir() + "/pubring";

     auto knownKeys = keyidsFromPubring(gpgDir);

+    ensure_socket_dir_exists();

     for (const auto & gpgkeyUrl : conf->gpgkey().getValue()) {

         auto keyInfos = retrieve(gpgkeyUrl);

         for (auto & keyInfo : keyInfos) {

@@ -908,13 +917,6 @@ void Repo::Impl::importRepoKeys()

             gpgImportKey(ctx, keyInfo.rawKey);

-            // Running gpg-agent kept opened sockets on the system.

-            // It tries to exit gpg-agent. Path to the communication socket is derived from homedir.

-            // The gpg-agent automaticaly removes all its socket before exit.

-            // Newer gpg-agent creates sockets under [/var]/run/user/{pid}/... if directory exists.

-            // In this case gpg-agent will not be exited.

-            killGpgAgent(ctx, gpgDir);

-

             logger->debug(tfm::format(_("repo %s: imported key 0x%s."), id, keyInfo.getId()));

         }