Convert properly UTF-8 to UTF-16

wchar_t is currently 16bit so converting a utf8 encoded characters not
in plane 0 (>= 0x10000) to wchar_t (that is calling char2uni) lead to a
-EINVAL return. This patch detect utf8 in cifs_strtoUTF16 and add special
code calling utf8s_to_utf16s.

Signed-off-by: Frediano Ziglio <frediano.ziglio@citrix.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

1 files changed, 22 insertions, 0 deletions

diff --git a/fs/cifs/cifs_unicode.c b/fs/cifs/cifs_unicode.c
index 53cf2aabce87..71d5d0a5f6b2 100644
--- a/fs/cifs/cifs_unicode.c
+++ b/fs/cifs/cifs_unicode.c
@@ -203,6 +203,27 @@ cifs_strtoUTF16(__le16 *to, const char *from, int len,
         int i;
         wchar_t wchar_to; /* needed to quiet sparse */
 
+        /* special case for utf8 to handle no plane0 chars */
+        if (!strcmp(codepage->charset, "utf8")) {
+                /*
+                 * convert utf8 -> utf16, we assume we have enough space
+                 * as caller should have assumed conversion does not overflow
+                 * in destination len is length in wchar_t units (16bits)
+                 */
+                i  = utf8s_to_utf16s(from, len, UTF16_LITTLE_ENDIAN,
+                                       (wchar_t *) to, len);
+
+                /* if success terminate and exit */
+                if (i >= 0)
+                        goto success;
+                /*
+                 * if fails fall back to UCS encoding as this
+                 * function should not return negative values
+                 * currently can fail only if source contains
+                 * invalid encoded characters
+                 */
+        }
+
         for (i = 0; len && *from; i++, from += charlen, len -= charlen) {
                 charlen = codepage->char2uni(from, len, &wchar_to);
                 if (charlen < 1) {
@@ -215,6 +236,7 @@ cifs_strtoUTF16(__le16 *to, const char *from, int len,
                 put_unaligned_le16(wchar_to, &to[i]);
         }
 
+success:
         put_unaligned_le16(0, &to[i]);
         return i;
 }