This commit was manufactured by cvs2svn to create branch

'GNUPG-1-9-BRANCH'.

1 files changed, 314 insertions, 0 deletions

diff --git a/agent/cache.c b/agent/cache.c
new file mode 100644
index 000000000..b6ab55085
--- /dev/null
+++ b/agent/cache.c
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+/* cache.c - keep a cache of passphrases
+ *	Copyright (C) 2002 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <assert.h>
+
+#include "agent.h"
+
+struct secret_data_s {
+  int  totallen; /* this includes the padding */
+  int  datalen;  /* actual data length */
+  char data[1];
+};
+
+typedef struct cache_item_s *ITEM;
+struct cache_item_s {
+  ITEM next;
+  time_t created;
+  time_t accessed;
+  int  ttl;  /* max. lifetime given in seonds */
+  int lockcount;
+  struct secret_data_s *pw;
+  char key[1];
+};
+
+
+static ITEM thecache;
+
+
+static void
+release_data (struct secret_data_s *data)
+{
+   xfree (data);
+}
+
+static struct secret_data_s *
+new_data (const void *data, size_t length)
+{
+  struct secret_data_s *d;
+  int total;
+
+  /* we pad the data to 32 bytes so that it get more complicated
+     finding something out by watching allocation patterns.  This is
+     usally not possible but we better assume nothing about our
+     secure storage provider*/
+  total = length + 32 - (length % 32);
+
+  d = gcry_malloc_secure (sizeof *d + total - 1);
+  if (d)
+    {
+      d->totallen = total;
+      d->datalen  = length;
+      memcpy (d->data, data, length);
+    }
+  return d;
+}
+
+
+/* check whether there are items to expire */
+static void
+housekeeping (void)
+{
+  ITEM r, rprev;
+  time_t current = gnupg_get_time ();
+
+  /* first expire the actual data */
+  for (r=thecache; r; r = r->next)
+    {
+      if (!r->lockcount && r->pw && r->accessed + r->ttl < current)
+        {
+          if (DBG_CACHE)
+            log_debug ("  expired `%s' (%ds after last access)\n",
+                       r->key, r->ttl);
+          release_data (r->pw);
+          r->pw = NULL;
+          r->accessed = current;
+        }
+    }
+
+  /* second, make sure that we also remove them based on the created stamp so
+     that the user has to enter it from time to time.  We do this every hour */
+  for (r=thecache; r; r = r->next)
+    {
+      if (!r->lockcount && r->pw && r->created + 60*60 < current)
+        {
+          if (DBG_CACHE)
+            log_debug ("  expired `%s' (1h after creation)\n", r->key);
+          release_data (r->pw);
+          r->pw = NULL;
+          r->accessed = current;
+        }
+    }
+
+  /* third, make sure that we don't have too many items in the list.
+     Expire old and unused entries after 30 minutes */
+  for (rprev=NULL, r=thecache; r; )
+    {
+      if (!r->pw && r->accessed + 60*30 < current)
+        {
+          if (r->lockcount)
+            {
+              log_error ("can't remove unused cache entry `%s' due to"
+                         " lockcount=%d\n",
+                         r->key, r->lockcount);
+              r->accessed += 60*10; /* next error message in 10 minutes */
+              rprev = r;
+              r = r->next;
+            }
+          else
+            {
+              ITEM r2 = r->next;
+              if (DBG_CACHE)
+                log_debug ("  removed `%s' (slot not used for 30m)\n", r->key);
+              xfree (r);
+              if (!rprev)
+                thecache = r2;
+              else
+                rprev->next = r2;
+              r = r2;
+            }
+        }
+      else
+        {
+          rprev = r;
+          r = r->next;
+        }
+    }
+}
+
+
+void
+agent_flush_cache (void)
+{
+  ITEM r;
+
+  if (DBG_CACHE)
+    log_debug ("agent_flush_cache\n");
+
+  for (r=thecache; r; r = r->next)
+    {
+      if (!r->lockcount && r->pw)
+        {
+          if (DBG_CACHE)
+            log_debug ("  flushing `%s'\n", r->key);
+          release_data (r->pw);
+          r->pw = NULL;
+          r->accessed = 0;
+        }
+      else if (r->lockcount && r->pw)
+        {
+          if (DBG_CACHE)
+            log_debug ("    marked `%s' for flushing\n", r->key);
+          r->accessed = 0;
+          r->ttl = 0;
+        }
+    }
+}
+
+
+
+/* Store DATA of length DATALEN in the cache under KEY and mark it
+   with a maximum lifetime of TTL seconds.  If there is already data
+   under this key, it will be replaced.  Using a DATA of NULL deletes
+   the entry */
+int
+agent_put_cache (const char *key, const char *data, int ttl)
+{
+  ITEM r;
+
+  if (DBG_CACHE)
+    log_debug ("agent_put_cache `%s'\n", key);
+  housekeeping ();
+
+  if (ttl < 1)
+    ttl = opt.def_cache_ttl;
+  if (!ttl)
+    return 0;
+
+  for (r=thecache; r; r = r->next)
+    {
+      if (!r->lockcount && !strcmp (r->key, key))
+        break;
+    }
+  if (r)
+    { /* replace */
+      if (r->pw)
+        {
+          release_data (r->pw);
+          r->pw = NULL;
+        }
+      if (data)
+        {
+          r->created = r->accessed = gnupg_get_time (); 
+          r->ttl = ttl;
+          r->pw = new_data (data, strlen (data)+1);
+          if (!r->pw)
+            log_error ("out of core while allocating new cache item\n");
+        }
+    }
+  else if (data)
+    { /* simply insert */
+      r = xtrycalloc (1, sizeof *r + strlen (key));
+      if (!r)
+        log_error ("out of core while allocating new cache control\n");
+      else
+        {
+          strcpy (r->key, key);
+          r->created = r->accessed = gnupg_get_time (); 
+          r->ttl = ttl;
+          r->pw = new_data (data, strlen (data)+1);
+          if (!r->pw)
+            {
+              log_error ("out of core while allocating new cache item\n");
+              xfree (r);
+            }
+          else
+            {
+              r->next = thecache;
+              thecache = r;
+            }
+        }
+    }
+  return 0;
+}
+
+
+/* Try to find an item in the cache */
+const char *
+agent_get_cache (const char *key, void **cache_id)
+{
+  ITEM r;
+
+  if (DBG_CACHE)
+    log_debug ("agent_get_cache `%s'...\n", key);
+  housekeeping ();
+
+  /* first try to find one with no locks - this is an updated cache
+     entry: We might have entries with a lockcount and without a
+     lockcount. */
+  for (r=thecache; r; r = r->next)
+    {
+      if (!r->lockcount && r->pw && !strcmp (r->key, key))
+        {
+          /* put_cache does only put strings into the cache, so we
+             don't need the lengths */
+          r->accessed = gnupg_get_time ();
+          if (DBG_CACHE)
+            log_debug ("... hit\n");
+          r->lockcount++;
+          *cache_id = r;
+          return r->pw->data;
+        }
+    }
+  /* again, but this time get even one with a lockcount set */
+  for (r=thecache; r; r = r->next)
+    {
+      if (r->pw && !strcmp (r->key, key))
+        {
+          r->accessed = gnupg_get_time ();
+          if (DBG_CACHE)
+            log_debug ("... hit (locked)\n");
+          r->lockcount++;
+          *cache_id = r;
+          return r->pw->data;
+        }
+    }
+  if (DBG_CACHE)
+    log_debug ("... miss\n");
+
+  *cache_id = NULL;
+  return NULL;
+}
+
+
+void
+agent_unlock_cache_entry (void **cache_id)
+{
+  ITEM r;
+
+  for (r=thecache; r; r = r->next)
+    {
+      if (r == *cache_id)
+        {
+          if (!r->lockcount)
+            log_error ("trying to unlock non-locked cache entry `%s'\n",
+                       r->key);
+          else
+            r->lockcount--;
+          return;
+        }
+    }
+}