Error when ePub containt a relatif path archive name

[un_pogaz]

Sigil can't load the ePub when they contain a relative path:

Possible evil or corrupt epub file name: OEBPS/../images/cover.jpg

The attached ePub is also the worst case, because it contains the same file with a valid file (but only the relative path is buggy, not the duplicate entry).

It's rare, and I'm sure in some cases the error is valid and nothing can be done (when you exit the archive for example).

PS: the bug is old. Ironically it was "quite" easy to find a ePub with this : The "Quick start guide for Calibre" 4e edition -by John Schember.

[KevinH]

Not an error in Sigil. Sigil will not load files outside the root path of the epub by design. No upward relative paths are needed in any epub. This is an attack vector that can be used to craft a malicious epub to overwrite system files. There was actually a CVE/security bug filed against Sigil (and "minizip") to prevent loading such epubs/zips.

Google "zip slip attack" for more details.

If you are 100% sure the epub has not been tampered with then manually unpack it and use AddExisting to add its pieces in proper form.