CIFS: Fix memory over bound bug in cifs_parse_mount_options

commit 4906e50b37e6f6c264e7ee4237343eb2b7f8d16d upstream.

While password processing we can get out of options array bound if
the next character after array is delimiter. The patch adds a check
if we reach the end.

Signed-off-by: Pavel Shilovsky <piastry@etersoft.ru>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index f6afb599dddd62266402343fb69796c39df819f4..cebbc2983c84aa244265c752d8d4d4a490e51a31 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -800,8 +800,7 @@ static int
 cifs_parse_mount_options(char *options, const char *devname,
                         struct smb_vol *vol)
 {
-       char *value;
-       char *data;
+       char *value, *data, *end;
        unsigned int  temp_len, i, j;
        char separator[2];
        short int override_uid = -1;
@@ -844,6 +843,7 @@ cifs_parse_mount_options(char *options, const char *devname,
        if (!options)
                return 1;
 
+       end = options + strlen(options);
        if (strncmp(options, "sep=", 4) == 0) {
                if (options[4] != 0) {
                        separator[0] = options[4];
@@ -908,6 +908,7 @@ cifs_parse_mount_options(char *options, const char *devname,
                        the only illegal character in a password is null */
 
                        if ((value[temp_len] == 0) &&
+                           (value + temp_len < end) &&
                            (value[temp_len+1] == separator[0])) {
                                /* reinsert comma */
                                value[temp_len] = separator[0];