From b3c987234d02d603369d337ae02261b6acc25075 Mon Sep 17 00:00:00 2001
From: Ben Kibbey <bjk@luxsci.net>
Date: Sat, 22 Dec 2012 18:35:48 -0500
Subject: [PATCH] Fix crash when/if gpg-agent dies.

---
 src/agent.c    | 10 ++++------
 src/commands.c | 32 ++++++++++++++++++++++++++------
 src/crypto.c   |  1 +
 src/pwmd.c     |  6 +++---
 4 files changed, 34 insertions(+), 15 deletions(-)

diff --git a/src/agent.c b/src/agent.c
index 83483f6f..96c0a979 100644
--- a/src/agent.c
+++ b/src/agent.c
@@ -132,7 +132,7 @@ static gpg_error_t
 launch_agent (struct agent_s *agent)
 {
   gpg_error_t rc;
-  assuan_context_t ctx;
+  assuan_context_t ctx = NULL;
   const char *t = NULL;
   static struct assuan_malloc_hooks mhooks = { xmalloc, xrealloc, xfree };
   char *s, buf[LINE_MAX];
@@ -182,7 +182,8 @@ launch_agent (struct agent_s *agent)
   strv_free (fields);
   if (rc)
     {
-      assuan_release (ctx);
+      if (ctx)
+	assuan_release (ctx);
       return rc;
     }
 
@@ -269,10 +270,7 @@ cleanup_agent (struct agent_s *agent)
     return;
 
   pinentry_free_opts (&agent->pinentry_opts);
-
-  if (agent->ctx)
-    agent_disconnect (agent);
-
+  agent_disconnect (agent);
   xfree (agent);
 }
 
diff --git a/src/commands.c b/src/commands.c
index 00e686cb..19c9b906 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -74,6 +74,22 @@
 #define OPT_DATA		0x0400
 #define OPT_NO_AGENT            0x0800
 
+#ifdef WITH_AGENT
+/* The GETCONFIG command, for example, may fail because pwmd lost the
+ * gpg-agent connection. Update the recovered agent ctx. */
+#define UPDATE_AGENT_CTX(client, crypto)	do {			\
+    if (crypto && crypto->agent && client->crypto && client->crypto->agent \
+	&& client->crypto->agent->ctx &&				\
+	crypto->agent->ctx != client->crypto->agent->ctx)		\
+      {									\
+	client->crypto->agent->ctx = crypto->agent->ctx;		\
+	crypto->agent->ctx = NULL;					\
+      }									\
+  }  while (0)
+#else
+#define UPDATE_AGENT_CTX(client, crypto)
+#endif
+
 struct command_table_s
 {
   const char *name;
@@ -216,7 +232,7 @@ cleanup_client (struct client_s *client)
 #ifdef WITH_AGENT
   struct pinentry_option_s agent_pin_opts;
 
-  if (crypto->agent)
+  if (crypto && crypto->agent)
     memcpy (&agent_pin_opts, &crypto->agent->pinentry_opts,
 	    sizeof(struct pinentry_option_s));
 #endif
@@ -232,8 +248,9 @@ cleanup_client (struct client_s *client)
   memcpy (&client->pinentry_opts, &pin_opts, sizeof(struct pinentry_option_s));
   client->flags |= no_pinentry ? FLAG_NO_PINENTRY : 0;
 #ifdef WITH_AGENT
-  memcpy (&crypto->agent->pinentry_opts, &agent_pin_opts,
-	  sizeof(struct pinentry_option_s));
+  if (crypto && crypto->agent)
+    memcpy (&crypto->agent->pinentry_opts, &agent_pin_opts,
+	    sizeof(struct pinentry_option_s));
 #endif
 }
 
@@ -2380,7 +2397,7 @@ getconfig_command (assuan_context_t ctx, char *line)
   paramp = str_down (paramp);
   if (!strcmp (paramp, "cipher") && fp)
     {
-      struct crypto_s *crypto;
+      struct crypto_s *crypto = NULL;
 
       rc = init_client_crypto (&crypto);
       if (!rc)
@@ -2399,6 +2416,7 @@ getconfig_command (assuan_context_t ctx, char *line)
 	    }
 	}
 
+      UPDATE_AGENT_CTX (client, crypto);
       cleanup_crypto (&crypto);
       if (rc && gpg_err_code (rc) != GPG_ERR_ENOENT)
 	return send_error (ctx, rc);
@@ -2408,7 +2426,7 @@ getconfig_command (assuan_context_t ctx, char *line)
     }
   else if (!strcmp (paramp, "cipher_iterations") && fp)
     {
-      struct crypto_s *crypto;
+      struct crypto_s *crypto = NULL;
 
       rc = init_client_crypto (&crypto);
       if (!rc)
@@ -2424,6 +2442,7 @@ getconfig_command (assuan_context_t ctx, char *line)
 	    }
 	}
 
+      UPDATE_AGENT_CTX (client, crypto);
       cleanup_crypto (&crypto);
       if (rc && gpg_err_code (rc) != GPG_ERR_ENOENT)
 	return send_error (ctx, rc);
@@ -3980,7 +3999,7 @@ keygrip_command (assuan_context_t ctx, char *line)
 {
   struct client_s *client = assuan_get_pointer (ctx);
   gpg_error_t rc;
-  struct crypto_s *crypto;
+  struct crypto_s *crypto = NULL;
   struct argv_s *args[] = {
     &(struct argv_s) {"sign", OPTION_TYPE_NOARG, parse_keygrip_opt_sign},
     NULL
@@ -4028,6 +4047,7 @@ keygrip_command (assuan_context_t ctx, char *line)
       xfree (hexgrip);
     }
 
+  UPDATE_AGENT_CTX (client, crypto);
   cleanup_crypto (&crypto);
   return send_error (ctx, rc);
 }
diff --git a/src/crypto.c b/src/crypto.c
index 50851034..8a62f590 100644
--- a/src/crypto.c
+++ b/src/crypto.c
@@ -679,6 +679,7 @@ init_client_crypto (struct crypto_s **crypto)
 
       if (rc)
 	{
+	  cleanup_agent (new->agent);
 	  xfree (new);
 	  return rc;
 	}
diff --git a/src/pwmd.c b/src/pwmd.c
index 18815e88..ce881ef8 100644
--- a/src/pwmd.c
+++ b/src/pwmd.c
@@ -148,7 +148,7 @@ catch_thread_signal (int sig, siginfo_t *info, void *ctx)
 static void
 cache_push_from_rcfile ()
 {
-  struct crypto_s *crypto;
+  struct crypto_s *crypto = NULL;
   char **cache_push;
   gpg_error_t rc = init_client_crypto (&crypto);
 
@@ -1059,7 +1059,7 @@ xml_import (const char *filename, const char *outfile,
   xmlChar *xmlbuf;
   xmlChar *xml;
   gpg_error_t rc;
-  struct crypto_s *crypto;
+  struct crypto_s *crypto = NULL;
   void *key = NULL;
   size_t keylen = 0;
   int algo = cipher ? cipher_string_to_gcrypt ((char *) cipher) :
@@ -2675,7 +2675,7 @@ main (int argc, char *argv[])
    */
   if (cache_push)
     {
-      struct crypto_s *crypto;
+      struct crypto_s *crypto = NULL;
       gpg_error_t rc = init_client_crypto (&crypto);
 
       if (rc)
-- 
2.11.4.GIT