From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Wed, 13 Jan 2021 17:19:37 +0000 (+0200)
Subject: lib-imap: Move unnecessary shift check to mbase64_decode_to_utf8()
X-Git-Tag: 2.3.14.rc1~59
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=40070778c06e38abfd55ae50035ec39975bd4ebf;p=thirdparty%2Fdovecot%2Fcore.git

lib-imap: Move unnecessary shift check to mbase64_decode_to_utf8()
---

diff --git a/src/lib-imap/imap-utf7.c b/src/lib-imap/imap-utf7.c
index 90abbc829f..ba97d90551 100644
--- a/src/lib-imap/imap-utf7.c
+++ b/src/lib-imap/imap-utf7.c
@@ -243,7 +243,12 @@ static int mbase64_decode_to_utf8(string_t *dest, const char **_src)
 			return -1;
 	}
 
-	/* found ending '-' */
+	/* Found the ending '-'. Make sure it's not followed by unnecessary
+	   shift. Note that '&' is always escaped as "&-" so it's not an
+	   unnecessary shift. */
+	if (src[1] == '&' && src[2] != '-')
+		return -1;
+
 	*_src = src + 1;
 	return 0;
 }
@@ -274,10 +279,6 @@ int imap_utf7_to_utf8(const char *src, string_t *dest)
 			} else {
 				if (mbase64_decode_to_utf8(dest, &p) < 0)
 					return -1;
-				if (p[0] == '&' && p[1] != '-') {
-					/* &...-& */
-					return -1;
-				}
 			}
 		} else {
 			str_append_c(dest, *p++);