Changeset fed4f76

Timestamp:

2015-01-16T19:50:25Z (10 years ago)

Author:

dequis <dx@…>

Branches:

master

Children:

ecbd22a

Parents:

4cff28f

Message:

Fix UTF8 nick truncation issues

When nicks exceeded the length limit, they were cut at 24 bytes and that
sometimes left invalid utf8 at the end, which made the nick_ok()
validation fail and often broke those nicks completely.

This adds a truncate_utf8 function to cut the string at a safe place

Also, the method to deduplicate nicks when there's no more place to add
underscores was changed to add "_XX" at the end, where XX are two random
hex chars. The previous method in those cases was increasing the value
of the first character of the nick... which leads to silly and confusing
results (i.e. FacebookUser -> GacebookUser)

Files:

• lib/misc.c (modified) (1 diff)
• lib/misc.h (modified) (1 diff)
• nick.c (modified) (3 diffs)

lib/misc.c

@@ -780 +780 @@
         return NULL;
 }
+
+/* Takes a string, truncates it where it's safe, returns the new length */
+int truncate_utf8( char *string, int maxlen )
+{
+        char *end;
+        g_utf8_validate( (const gchar *) string, maxlen, (const gchar **) &end );
+        *end = '\0';
+        return end - string;
+}

lib/misc.h

@@ -150 +150 @@
 G_MODULE_EXPORT char **split_command_parts( char *command, int limit );
 G_MODULE_EXPORT char *get_rfc822_header( const char *text, const char *header, int len );
+G_MODULE_EXPORT int truncate_utf8( char *string, int maxlen );
 
 #endif

nick.c

@@ -227 +227 @@
         {
                 nick_strip( irc, rets );
-                rets[MAX_NICK_LENGTH] = '\0';
+                truncate_utf8( rets, MAX_NICK_LENGTH );
                 return rets;
         }
@@ -252 +252 @@
                 else
                 {
-                        nick[0] ++;
+                        /* We've got no more space for underscores,
+                           so truncate it and replace the last three
+                           chars with a random "_XX" suffix */
+                        int len = truncate_utf8( nick, MAX_NICK_LENGTH - 3 );
+                        nick[len] = '_';
+                        g_snprintf(nick + len + 1, 3, "%2x", rand() );
                 }
                 
@@ -400 +405 @@
                 if( strlen( down ) > strlen( nick ) )
                 {
-                        /* Well crap. Corrupt it if we have to. */
-                        down[strlen(nick)] = '\0';
+                        truncate_utf8( down, strlen(nick) );
                 }
                 strcpy( nick, down );