[gnumeric] xls: improve handling of broken files.

[Morten Welinder <mortenw src gnome org>]

commit 754816d0dd3b4fc93c4590ceb4ecc6a20162c5d8
Author: Morten Welinder <terra gnome org>
Date:   Sat Apr 20 12:02:11 2013 -0400

    xls: improve handling of broken files.

 NEWS                          | 1 +
 plugins/excel/ChangeLog       | 6 ++++++
 plugins/excel/ms-excel-read.c | 3 ++-
 3 files changed, 9 insertions(+), 1 deletion(-)
---
diff --git a/NEWS b/NEWS
index 581169c..78e1b99 100644
--- a/NEWS
+++ b/NEWS
@@ -57,6 +57,7 @@ Morten:
        * Improve vertical toolbars.  [#590889]
        * Merge long format toolbar into regular one.
        * Work around gtk+ behaviour change.  [#689283]
+       * Improve handling of broken xls.  [#698424]
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.1
diff --git a/plugins/excel/ChangeLog b/plugins/excel/ChangeLog
index 192f4eb..22c2502 100644
--- a/plugins/excel/ChangeLog
+++ b/plugins/excel/ChangeLog
@@ -1,3 +1,9 @@
+2013-04-20  Morten Welinder  <terra gnome org>
+
+       * ms-excel-read.c (excel_read_name_str): Make sure we don't end up
+       requesting (size_t)-1 characters worth of data.  Fixes #698424,
+       initial item.
+
 2013-04-15  Morten Welinder  <terra gnome org>
 
        * ms-formula-write.c (write_arrays): Handle empty values properly.
diff --git a/plugins/excel/ms-excel-read.c b/plugins/excel/ms-excel-read.c
index afa8ceb..a01997c 100644
--- a/plugins/excel/ms-excel-read.c
+++ b/plugins/excel/ms-excel-read.c
@@ -3748,7 +3748,7 @@ excel_read_name_str (GnmXLImporter *importer,
         * and stored the id as a character (possibly two byte).
         * NOTE : len is in _characters_ (not bytes) does not include
         *      the header */
-       if (is_builtin) {
+       if (is_builtin && *name_len) {
                guint8 const *str = data;
                char const *builtin;
 
@@ -3952,6 +3952,7 @@ excel_read_NAME (BiffQuery *q, GnmXLImporter *importer, ExcelReadSheet *esheet)
                sheet_index = 0; /* no sheets */
        }
 
+       XL_NEED_BYTES (name_len);
        name = excel_read_name_str (importer, data, &name_len, builtin_name);
        XL_NEED_BYTES (name_len);
        data += name_len;