cifs: add replacement for cifs_strtoUCS_le called cifs_from_ucs2
Add a replacement function for cifs_strtoUCS_le. cifs_from_ucs2
takes args for the source and destination length so that we can ensure
that the function is confined within the intended buffers.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Suresh Jayaraman <sjayaraman@suse.de>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/cifs_unicode.c b/fs/cifs/cifs_unicode.c
index 7d75272..8389f35 100644
--- a/fs/cifs/cifs_unicode.c
+++ b/fs/cifs/cifs_unicode.c
@@ -26,6 +26,130 @@
#include "cifs_debug.h"
/*
+ * 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;
+ }
+
+ /* properly null-terminate string */
+ for (i = 0; i < nullsize; i++)
+ to[outlen++] = 0;
+
+ return outlen;
+}
+
+/*
* NAME: cifs_strfromUCS()
*
* FUNCTION: Convert little-endian unicode string to character string