zip: Improve bid for huge EOCDs (#2159)

Cast any of cd_offset or cd_size to int64_t to avoid truncation of
result because both variables are of type uint32_t.

The calculation happens before comparison with current_offset, so it is
not automatically expanded to int64_t during calculation.

diff --git a/libarchive/archive_read_support_format_zip.c b/libarchive/archive_read_support_format_zip.c
index c9759eaf9a898b1e5ac6c414647914ab582699b2..ac80a99ad9cb4ad11876631abafe2291b77325c1 100644 (file)
--- a/libarchive/archive_read_support_format_zip.c
+++ b/libarchive/archive_read_support_format_zip.c
@@ -3680,7 +3680,7 @@ read_eocd(struct zip *zip, const char *p, int64_t current_offset)
        if (archive_le16dec(p + 10) != archive_le16dec(p + 8))
                return 0;
        /* Central directory can't extend beyond start of EOCD record. */
-       if (cd_offset + cd_size > current_offset)
+       if ((int64_t)cd_offset + cd_size > current_offset)
                return 0;
 
        /* Save the central directory location for later use. */