Archive entry names are attacker controlled. `rclone archive extract` stripped
only a leading `./` and then joined the entry name onto the destination
directory with `path.Join`, which collapses `..` segments. An entry such as
`../escaped.txt` extracted into `:s3:bucket/safe/prefix` therefore resolved to
`bucket/safe/escaped.txt`, outside the selected `prefix` directory - a path
traversal ("Zip Slip") attack that could create or overwrite sibling objects on
any destination remote.
Entry names are now validated before use: a leading `./` is still stripped (tar
archives created with `tar -czf archive.tar.gz .` rely on this), but any entry
with a `..` path component is rejected. Both `/` and `\` are treated as
separators when looking for `..`, as the local backend treats `\` as a path
separator on Windows.
Fixes: GHSA-4vr5-p2gc-h23p
The files.com integration tests for rcat/copyurl were failing because
fs/account.Account was declaring a ReadAt method when the underlying
handle did not support it. The files.com SDK decided to use the ReadAt
method to speed transfers up which failed.
ReadAt and Seek methods were added in this commit to support the
archive command:
409dc75328 accounting: add io.Seeker/io.ReaderAt support to accounting.Account
This fixes the problem by adding new methods to the Account object
WithSeeker/WithReaderAt/WithReadAtSeeker which produce an object with
the desired methods or errors if it isn't possible.
This stops Account advertising things it can't do which is bad Go
practice.
Tar files created from the current directory (e.g. tar -czf archive.tar.gz .)
produce entries prefixed with "./". When extracting, rclone's character
encoding replaces the "." with a full-width dot (U+FF0E), creating a
spurious directory instead of merging into the destination root.
Strip the leading "./" from NameInArchive before processing. Only "./"
is stripped specifically to avoid enabling path traversal attacks via
"../".
Fixes#9168
Nick Craig-Wood
Varun ChawlaandGitHub
n4n5andGitHub
Fawzib RojasandNick Craig-Wood