Fix truncation of long filenames in attachments.

Currently mutt truncates long filenames in attachments and doesn't
take into account UTF-8 character size. If filename is truncated in
the middle of multi-byte UTF-8 character (last character is bad),
then some mail clients assume whole attachment name bad and don't
display its name (use 'Noname' instead).

Filenames can be up to 255 *characters* long depending on used
filesystem. ReiserFS, NFTS, FAT, APFS and some other supports up to
255 characters.
In the worst case 255 characters in UTF-8 will take 255*4 = 1020
bytes. Every non-ascii byte in the filename will be encoded using 3
bytes (for example, %8D).
So 'Content-Disposition' will take in the worst case up to: 1020*3 =
3060 bytes. Therefore even LONG_STRING (1024) isn't enough.

diff --git a/sendlib.c b/sendlib.c
index 8291aa8ec2928f581738d3203707a49bffdddb3d..8a772823012ed1b415c2fbbda031aa9a14818186 100644 (file)
--- a/sendlib.c
+++ b/sendlib.c
@@ -293,7 +293,7 @@ static void encode_8bit (FGETCONV *fc, FILE *fout, int istext)
 int mutt_write_mime_header (BODY *a, FILE *f)
 {
   PARAMETER *p;
-  char buffer[STRING];
+  char buffer[HUGE_STRING];
   char *t;
   char *fn;
   int len;