1 files changed, 181 insertions, 17 deletions

diff --git a/fs/cifs/cifs_unicode.c b/fs/cifs/cifs_unicode.c
index 7d75272a6b3..60e3c4253de 100644
--- a/fs/cifs/cifs_unicode.c
+++ b/fs/cifs/cifs_unicode.c
@@ -1,7 +1,7 @@
 /*
  *   fs/cifs/cifs_unicode.c
  *
- *   Copyright (c) International Business Machines  Corp., 2000,2005
+ *   Copyright (c) International Business Machines  Corp., 2000,2009
  *   Modified by Steve French (sfrench@us.ibm.com)
  *
  *   This program is free software;  you can redistribute it and/or modify
@@ -26,31 +26,157 @@
 #include "cifs_debug.h"
 
 /*
- * NAME:	cifs_strfromUCS()
- *
- * FUNCTION:	Convert little-endian unicode string to character string
+ * cifs_ucs2_bytes - how long will a string be after conversion?
+ * @ucs - pointer to input string
+ * @maxbytes - don't go past this many bytes of input string
+ * @codepage - destination codepage
  *
+ * Walk a ucs2le string and return the number of bytes that the string will
+ * be after being converted to the given charset, not including any null
+ * termination required. Don't walk past maxbytes in the source buffer.
  */
 int
-cifs_strfromUCS_le(char *to, const __le16 *from,
-		   int len, const struct nls_table *codepage)
+cifs_ucs2_bytes(const __le16 *from, int maxbytes,
+		const struct nls_table *codepage)
 {
 	int i;
-	int outlen = 0;
+	int charlen, outlen = 0;
+	int maxwords = maxbytes / 2;
+	char tmp[NLS_MAX_CHARSET_SIZE];
 
-	for (i = 0; (i < len) && from[i]; i++) {
-		int charlen;
-		/* 2.4.0 kernel or greater */
-		charlen =
-		    codepage->uni2char(le16_to_cpu(from[i]), &to[outlen],
-				       NLS_MAX_CHARSET_SIZE);
-		if (charlen > 0) {
+	for (i = 0; from[i] && i < maxwords; i++) {
+		charlen = codepage->uni2char(le16_to_cpu(from[i]), tmp,
+					     NLS_MAX_CHARSET_SIZE);
+		if (charlen > 0)
 			outlen += charlen;
-		} else {
-			to[outlen++] = '?';
+		else
+			outlen++;
+	}
+
+	return outlen;
+}
+
+/*
+ * cifs_mapchar - convert a little-endian char to proper char in codepage
+ * @target - where converted character should be copied
+ * @src_char - 2 byte little-endian source character
+ * @cp - codepage to which character should be converted
+ * @mapchar - should character be mapped according to mapchars mount option?
+ *
+ * This function handles the conversion of a single character. It is the
+ * responsibility of the caller to ensure that the target buffer is large
+ * enough to hold the result of the conversion (at least NLS_MAX_CHARSET_SIZE).
+ */
+static int
+cifs_mapchar(char *target, const __le16 src_char, const struct nls_table *cp,
+	     bool mapchar)
+{
+	int len = 1;
+
+	if (!mapchar)
+		goto cp_convert;
+
+	/*
+	 * BB: Cannot handle remapping UNI_SLASH until all the calls to
+	 *     build_path_from_dentry are modified, as they use slash as
+	 *     separator.
+	 */
+	switch (le16_to_cpu(src_char)) {
+	case UNI_COLON:
+		*target = ':';
+		break;
+	case UNI_ASTERIK:
+		*target = '*';
+		break;
+	case UNI_QUESTION:
+		*target = '?';
+		break;
+	case UNI_PIPE:
+		*target = '|';
+		break;
+	case UNI_GRTRTHAN:
+		*target = '>';
+		break;
+	case UNI_LESSTHAN:
+		*target = '<';
+		break;
+	default:
+		goto cp_convert;
+	}
+
+out:
+	return len;
+
+cp_convert:
+	len = cp->uni2char(le16_to_cpu(src_char), target,
+			   NLS_MAX_CHARSET_SIZE);
+	if (len <= 0) {
+		*target = '?';
+		len = 1;
+	}
+	goto out;
+}
+
+/*
+ * cifs_from_ucs2 - convert utf16le string to local charset
+ * @to - destination buffer
+ * @from - source buffer
+ * @tolen - destination buffer size (in bytes)
+ * @fromlen - source buffer size (in bytes)
+ * @codepage - codepage to which characters should be converted
+ * @mapchar - should characters be remapped according to the mapchars option?
+ *
+ * Convert a little-endian ucs2le string (as sent by the server) to a string
+ * in the provided codepage. The tolen and fromlen parameters are to ensure
+ * that the code doesn't walk off of the end of the buffer (which is always
+ * a danger if the alignment of the source buffer is off). The destination
+ * string is always properly null terminated and fits in the destination
+ * buffer. Returns the length of the destination string in bytes (including
+ * null terminator).
+ *
+ * Note that some windows versions actually send multiword UTF-16 characters
+ * instead of straight UCS-2. The linux nls routines however aren't able to
+ * deal with those characters properly. In the event that we get some of
+ * those characters, they won't be translated properly.
+ */
+int
+cifs_from_ucs2(char *to, const __le16 *from, int tolen, int fromlen,
+		 const struct nls_table *codepage, bool mapchar)
+{
+	int i, charlen, safelen;
+	int outlen = 0;
+	int nullsize = nls_nullsize(codepage);
+	int fromwords = fromlen / 2;
+	char tmp[NLS_MAX_CHARSET_SIZE];
+
+	/*
+	 * because the chars can be of varying widths, we need to take care
+	 * not to overflow the destination buffer when we get close to the
+	 * end of it. Until we get to this offset, we don't need to check
+	 * for overflow however.
+	 */
+	safelen = tolen - (NLS_MAX_CHARSET_SIZE + nullsize);
+
+	for (i = 0; i < fromwords && from[i]; i++) {
+		/*
+		 * check to see if converting this character might make the
+		 * conversion bleed into the null terminator
+		 */
+		if (outlen >= safelen) {
+			charlen = cifs_mapchar(tmp, from[i], codepage, mapchar);
+			if ((outlen + charlen) > (tolen - nullsize))
+				break;
 		}
+
+		/* put converted char into 'to' buffer */
+		charlen = cifs_mapchar(&to[outlen], from[i], codepage, mapchar);
+		outlen += charlen;
 	}
-	to[outlen] = 0;
+
+	/* properly null-terminate string */
+	for (i = 0; i < nullsize; i++)
+		to[outlen++] = 0;
+
 	return outlen;
 }
 
@@ -88,3 +214,41 @@ cifs_strtoUCS(__le16 *to, const char *from, int len,
 	return i;
 }
 
+/*
+ * cifs_strndup_from_ucs - copy a string from wire format to the local codepage
+ * @src - source string
+ * @maxlen - don't walk past this many bytes in the source string
+ * @is_unicode - is this a unicode string?
+ * @codepage - destination codepage
+ *
+ * Take a string given by the server, convert it to the local codepage and
+ * put it in a new buffer. Returns a pointer to the new string or NULL on
+ * error.
+ */
+char *
+cifs_strndup_from_ucs(const char *src, const int maxlen, const bool is_unicode,
+	     const struct nls_table *codepage)
+{
+	int len;
+	char *dst;
+
+	if (is_unicode) {
+		len = cifs_ucs2_bytes((__le16 *) src, maxlen, codepage);
+		len += nls_nullsize(codepage);
+		dst = kmalloc(len, GFP_KERNEL);
+		if (!dst)
+			return NULL;
+		cifs_from_ucs2(dst, (__le16 *) src, len, maxlen, codepage,
+			       false);
+	} else {
+		len = strnlen(src, maxlen);
+		len++;
+		dst = kmalloc(len, GFP_KERNEL);
+		if (!dst)
+			return NULL;
+		strlcpy(dst, src, len);
+	}
+
+	return dst;
+}
+