dovecot-2.2: lib-imap: imap-utf7 - reject encoded simple ASCII

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/0c0559782618
changeset: 17661:0c0559782618
user:      Phil Carmody <phil at dovecot.fi>
date:      Mon Jul 28 16:49:47 2014 +0300
description:
lib-imap: imap-utf7 - reject encoded simple ASCII
"Modified BASE64 MUST NOT be used to represent any printing US-ASCII
character which can represent itself."

"The character "&" (0x26) is represented by the two-octet sequence "&-""

Therefore any mBASE64 sequence containing any character between 0x20 and
0x7e is invalid.

Signed-off-by: Phil Carmody <phil at dovecot.fi>

diffstat:

 src/lib-imap/imap-utf7.c |  6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diffs (17 lines):

diff -r 6abfa33c73a8 -r 0c0559782618 src/lib-imap/imap-utf7.c
--- a/src/lib-imap/imap-utf7.c	Mon Jul 28 16:49:47 2014 +0300
+++ b/src/lib-imap/imap-utf7.c	Mon Jul 28 16:49:47 2014 +0300
@@ -148,7 +148,13 @@
 	if (high < UTF16_SURROGATE_HIGH_FIRST ||
 	    high > UTF16_SURROGATE_HIGH_MAX) {
 		/* single byte */
+		size_t oldlen = str_len(dest);
 		uni_ucs4_to_utf8_c(high, dest);
+		if (str_len(dest) - oldlen == 1) {
+			unsigned char last = str_data(dest)[oldlen];
+			if (last >= 0x20 && last < 0x7f)
+				return -1;
+		}
 		*_pos = (pos + 2) % 4;
 		return 0;
 	}