Avoid left-shift overflow of signed integer

In libarchive/archive_write_set_format_zip.c there are two calls to
archive_le32enc whose second argument is of the form

 archive_entry_mode(zip->entry) << 16

However, the return type from archive_entry_mode may be a signed integer
so the shift may overflow.  Since the second argument of archive_le32enc
expects uint32_t anyway, simply cast to that prior to shifting.

diff --git a/libarchive/archive_write_set_format_zip.c b/libarchive/archive_write_set_format_zip.c
index 975a4684f2480ed4a0c4a0873511b0b6390d5158..ed5a00b4163758f3c3f17db2d4985bcc0d4646d4 100644 (file)
--- a/libarchive/archive_write_set_format_zip.c
+++ b/libarchive/archive_write_set_format_zip.c
@@ -820,7 +820,7 @@ archive_write_zip_header(struct archive_write *a, struct archive_entry *entry)
        archive_le16enc(zip->file_header + 28, (uint16_t)filename_length);
        /* Following Info-Zip, store mode in the "external attributes" field. */
        archive_le32enc(zip->file_header + 38,
-           archive_entry_mode(zip->entry) << 16);
+           ((uint32_t)archive_entry_mode(zip->entry)) << 16);
        e = cd_alloc(zip, filename_length);
        /* If (e == NULL) XXXX */
        copy_path(zip->entry, e);
@@ -939,7 +939,7 @@ archive_write_zip_header(struct archive_write *a, struct archive_entry *entry)
                }
                if (included & 4) {
                        archive_le32enc(e,  /* external file attributes */
-                           archive_entry_mode(zip->entry) << 16);
+                           ((uint32_t)archive_entry_mode(zip->entry)) << 16);
                        e += 4;
                }
                if (included & 8) {