Add /copykey command

2 files changed, 67 insertions, 2 deletions

diff --git a/README b/README
index f710e0f..5cab819 100644
--- a/README
+++ b/README
@@ -37,11 +37,11 @@ Commands
 
     Sets the encryption key for the nick or channel to password. The keys
     are stored in the configuration file in ~/.config/hexchat/blow.ini
-    
+
     Optionally, the block cipher mode for outgoing messages may be specified.
     If unspecified it will be ECB for backwards compatibility, but for
     greater security, please use CBC mode if possible.
-    
+
     For incoming messages, the block cipher mode is auto-detected, regardless
     of which mode was configured with this command.
 
@@ -51,6 +51,16 @@ Commands
     Sets the cipher mode to ECB or CBC. See /setkey.
 
 
+/copykey  from [to]
+
+    Copies the key from the given channel or nick. If no "to" nick or channel
+    is given, then it copies to the one which is currently open.
+
+    This command can be used to use an existing channel key when chatting
+    with a single user. To do so, open a dialog with the user and type
+    /copykey #nameofchannel
+
+
 /delkey  nick-or-#channel
 
     Deletes the given nick or channel from the configuration file.
diff --git a/plugin_xchat.c b/plugin_xchat.c
index 8e6197b..9f10a05 100644
--- a/plugin_xchat.c
+++ b/plugin_xchat.c
@@ -41,12 +41,14 @@
 #include "fish.h"
 #include "keystore.h"
 #include "irc.h"
+#include "misc.h"
 
 static const char plugin_name[] = "FiSHLiM";
 static const char plugin_desc[] = "Encryption plugin for the FiSH protocol. Less is More!";
 static const char plugin_version[] = "0.0.19";
 
 static const char usage_setkey[] = "Usage: SETKEY [<nick or #channel>] [<mode>:]<password>, sets the key for a channel or nick. Modes: ECB, CBC";
+static const char usage_copykey[] = "Usage: COPYKEY <from nick or #channel> [<to nick or #channel>], copies the key from another channel or nick.";
 static const char usage_ciphermode[] = "Usage: CIPHERMODE [<nick or #channel>] <mode>, sets the cipher mode for a channel or nick to ECB or CBC";
 static const char usage_delkey[] = "Usage: DELKEY <nick or #channel>, deletes the key for a channel or nick";
 
@@ -241,6 +243,58 @@ static int handle_setkey(char *word[], char *word_eol[], void *userdata) {
 }
 
 /**
+ * Command handler for /copykey
+ */
+static int handle_copykey(char *word[], char *word_eol[], void *userdata) {
+    const char *from, *to;
+    bool is_cbc;
+    
+    // Check syntax
+    if (*word[2] == '\0') {
+        hexchat_printf(ph, "%s\n", usage_copykey);
+        return HEXCHAT_EAT_HEXCHAT;
+    }
+    
+    if (*word[3] == '\0') {
+        // /copykey #from
+        from = word_eol[2];
+        to = hexchat_get_info(ph, "channel");
+    } else {
+        // /copykey #from #to
+        from = word[2];
+        to = word_eol[3];
+    }
+    
+    // Get the key of the old nick/channel
+    char *key = keystore_get_key(from, &is_cbc);
+    if (!key) {
+        hexchat_printf(ph, "\00305Could not get key of %s\n", from);
+        return HEXCHAT_EAT_HEXCHAT;
+    }
+    
+    // Prevent accidental overwites
+    char *existingkey = keystore_get_key(to, NULL);
+    if (existingkey) {
+        secure_erase(existingkey, strlen(existingkey));
+        free(existingkey);
+        hexchat_printf(ph, "\00305A key already exists for %s. "
+                       "You can use /delkey to delete it.\n", to);
+        return HEXCHAT_EAT_HEXCHAT;
+    }
+    
+    // Set the key of the new nick/channel
+    if (keystore_store_key(to, key, is_cbc)) {
+        hexchat_printf(ph, "Copied key from %s to %s (%s)\n", from, to, is_cbc ? "CBC mode" : "old insecure ECB mode");
+    } else {
+        hexchat_printf(ph, "\00305Failed to store key in blow.ini\n");
+    }
+    
+    secure_erase(key, strlen(key));
+    free(key);
+    return HEXCHAT_EAT_HEXCHAT;
+}
+
+/**
  * Command handler for /ciphermode
  */
 static int handle_ciphermode(char *word[], char *word_eol[], void *userdata) {
@@ -334,6 +388,7 @@ int hexchat_plugin_init(hexchat_plugin *plugin_handle,
     
     /* Register commands */
     hexchat_hook_command(ph, "SETKEY", HEXCHAT_PRI_NORM, handle_setkey, usage_setkey, NULL);
+    hexchat_hook_command(ph, "COPYKEY", HEXCHAT_PRI_NORM, handle_copykey, usage_copykey, NULL);
     hexchat_hook_command(ph, "CIPHERMODE", HEXCHAT_PRI_NORM, handle_ciphermode, usage_ciphermode, NULL);
     hexchat_hook_command(ph, "DELKEY", HEXCHAT_PRI_NORM, handle_delkey, usage_delkey, NULL);