[gmime-devel] [PATCH 6/5 :P] Avoid trying to replay the session key unless we have gpg >= 2.1.16

[Daniel Kahn Gillmor <dkg fifthhorseman net>]

---
 tests/test-pgpmime.c | 20 +++++++++++------
 tests/testsuite.c    | 63 +++++++++++++++++++++++++++++++++++++++++++---------
 tests/testsuite.h    |  1 +
 3 files changed, 66 insertions(+), 18 deletions(-)

diff --git a/tests/test-pgpmime.c b/tests/test-pgpmime.c
index c671c9b..e3ca614 100644
--- a/tests/test-pgpmime.c
+++ b/tests/test-pgpmime.c
@@ -443,7 +443,7 @@ int main (int argc, char *argv[])
        char *key;
        int i;
        GMimeStream *stream = NULL, *cleartext = NULL;
-       char *session_key;
+       char *session_key = NULL;
        
        g_mime_init (0);
        
@@ -496,13 +496,16 @@ int main (int argc, char *argv[])
        try {
                _construct_example (ctx, FALSE, &cleartext, &stream);
                session_key = test_multipart_encrypted (ctx, FALSE, cleartext, stream, NULL);
-               g_free (test_multipart_encrypted (ctx, FALSE, cleartext, stream, session_key));
+               if (testsuite_can_safely_override_session_key ())
+                       g_free (test_multipart_encrypted (ctx, FALSE, cleartext, stream, session_key));
                testsuite_check_passed ();
        } catch (ex) {
                testsuite_check_failed ("multipart/encrypted failed: %s", ex->message);
        } finally;
-       g_object_unref (cleartext);
-       g_object_unref (stream);
+       if (cleartext)
+               g_object_unref (cleartext);
+       if (stream)
+               g_object_unref (stream);
        cleartext = stream = NULL;
        if (session_key) {
                memset (session_key, 0, strlen (session_key));
@@ -514,13 +517,16 @@ int main (int argc, char *argv[])
        try {
                _construct_example (ctx, TRUE, &cleartext, &stream);
                session_key = test_multipart_encrypted (ctx, TRUE, cleartext, stream, NULL);
-               g_free (test_multipart_encrypted (ctx, TRUE, cleartext, stream, session_key));
+               if (testsuite_can_safely_override_session_key ())
+                       g_free (test_multipart_encrypted (ctx, TRUE, cleartext, stream, session_key));
                testsuite_check_passed ();
        } catch (ex) {
                testsuite_check_failed ("multipart/encrypted+sign failed: %s", ex->message);
        } finally;
-       g_object_unref (cleartext);
-       g_object_unref (stream);
+       if (cleartext)
+               g_object_unref (cleartext);
+       if (stream)
+               g_object_unref (stream);
        cleartext = stream = NULL;
        if (session_key) {
                memset (session_key, 0, strlen (session_key));
diff --git a/tests/testsuite.c b/tests/testsuite.c
index 68f9522..6d6e6aa 100644
--- a/tests/testsuite.c
+++ b/tests/testsuite.c
@@ -350,39 +350,80 @@ g_throw (Exception *ex)
        longjmp (env->env, 1);
 }
 
-static int
-is_gpg_modern (void)
+static const char *
+get_gpg_version (void)
 {
+       static int found = 0;
+       static char version[1024];
        const char vheader[] = "gpg (GnuPG) ";
        char *vstring = NULL;
        size_t vlen = 0;
        FILE *vpipe;
        int ret;
+
+       if (found)
+               return version;
        
        if ((vpipe = popen ("gpg --version", "r")) == NULL)
-               return 0;
+               return NULL;
        
        if (getline (&vstring, &vlen, vpipe) == -1) {
                free (vstring);
                pclose (vpipe);
-               return 0;
+               return NULL;
        }
        
        pclose (vpipe);
        
        if (strncmp (vstring, vheader, sizeof (vheader) - 1)) {
                free (vstring);
-               return 0;
+               return NULL;
        }
-       
-       ret = (vstring[sizeof (vheader) - 1] > '2') ||
-               (vstring[sizeof (vheader) - 1] == '2' &&
-                vstring[sizeof (vheader)] == '.' &&
-                vstring[sizeof (vheader) + 1] >= '1');
+
+       strncpy (version, vstring + sizeof (vheader) - 1, sizeof (version) - 1);
+       version[sizeof (version) - 1] = '\0';
        
        free (vstring);
+
+       found = 1;
+       return version;
+}
+
+static int
+is_gpg_modern (void)
+{
+       const char *ver = get_gpg_version ();
+
+       if (!ver)
+               return 0;
+       
+       return (ver[0] > '2') ||
+               (ver[0] == '2' &&
+                ver[1] == '.' &&
+                ver[2] >= '1');
+}
+
+/* in versions of gpg before 2.1.16, the only mechanism to override
+   the session key was --override-session-key, which leaks its
+   argument to the process table.
+
+   in 2.1.16, gpg introduced --override-session-key-fd, which is what
+   gmime uses to be safe.
+*/
+
+int
+testsuite_can_safely_override_session_key (void)
+{
+       const char *ver = get_gpg_version ();
+
+       if (!ver)
+               return 0;
        
-       return ret;
+       return (ver[0] > '2') ||
+               ((ver[0] == '2' && ver[1] == '.' ) &&
+                ((ver[2] > '1') ||
+                 ((ver[2] == '1' && ver[3] == '.') &&
+                  (atoi(ver+4) >= 16))));
 }
 
 int
diff --git a/tests/testsuite.h b/tests/testsuite.h
index a5f9392..87d3126 100644
--- a/tests/testsuite.h
+++ b/tests/testsuite.h
@@ -48,6 +48,7 @@ int testsuite_total_errors (void);
 /* GnuPG test suite utility functions */
 int testsuite_setup_gpghome (void);
 int testsuite_destroy_gpghome (void);
+int testsuite_can_safely_override_session_key (void);
 
 /*#if __GNUC__ > 2 || (__GNUC__ == 2 && __GNUC_MINOR__ >= 96)
 #define G_GNUC_NORETURN __attribute__((noreturn))
-- 
2.10.2