Changeset 997 for trunk

Timestamp:

Oct 13, 2006, 12:26:35 AM (16 years ago)

Author:

joshe

Message:

Prevent overflow when reading/converting strings from the torrent metainfo.

File:

• trunk/libtransmission/metainfo.c (modified) (8 diffs)

trunk/libtransmission/metainfo.c

@@ -30 +30 @@
  * Local prototypes
  **********************************************************************/
-static void strcatUTF8( char *, char * );
+#define strcatUTF8( dst, src) _strcatUTF8( (dst), sizeof( dst ), (src) )
+static void _strcatUTF8( char *, int, char * );
 
 /***********************************************************************
@@ -301 +302 @@
  * character, we assume it is ISO 8859-1 and convert it to UTF-8.
  **********************************************************************/
-static void strcatUTF8( char * s, char * append )
+#define WANTBYTES( want, got ) \
+    if( (want) > (got) ) { return; } else { (got) -= (want); }
+static void _strcatUTF8( char * s, int len, char * append )
 {
     char * p;
@@ -309 +312 @@
     {
         s++;
+        len--;
     }
 
@@ -317 +321 @@
         {
             /* ASCII character */
+            WANTBYTES( 1, len );
             *(s++) = *(p++);
             continue;
@@ -324 +329 @@
         {
             /* 2-bytes UTF-8 character */
+            WANTBYTES( 2, len );
             *(s++) = *(p++); *(s++) = *(p++);
             continue;
@@ -332 +338 @@
         {
             /* 3-bytes UTF-8 character */
+            WANTBYTES( 3, len );
             *(s++) = *(p++); *(s++) = *(p++);
             *(s++) = *(p++);
@@ -341 +348 @@
         {
             /* 4-bytes UTF-8 character */
+            WANTBYTES( 4, len );
             *(s++) = *(p++); *(s++) = *(p++);
             *(s++) = *(p++); *(s++) = *(p++);
@@ -347 +355 @@
 
         /* ISO 8859-1 -> UTF-8 conversion */
+        WANTBYTES( 2, len );
         *(s++) = 0xC0 | ( ( *p & 0xFF ) >> 6 );
         *(s++) = 0x80 | ( *(p++) & 0x3F );