Leveraged the existing verification code by making it also check the
retrievalSecurityPolicy.
Also, prevented getViaTmp from running the download action at all when the
retrievalSecurityPolicy is going to prevent verifying and so storing it.
Added annex.security.allow-unverified-downloads. A per-remote version
would be nice to have too, but would need more plumbing, so KISS.
(Bill the Cat reference not too over the top I hope. The point is to
make this something the user reads the documentation for before using.)
A few calls to verifyKeyContent and getViaTmp, that don't
involve downloads from remotes, have RetrievalAllKeysSecure hard-coded.
It was also hard-coded for P2P.Annex and Command.RecvKey,
to match the values of the corresponding remotes.
A few things use retrieveKeyFile/retrieveKeyFileCheap without going
through getViaTmp.
* Command.Fsck when downloading content from a remote to verify it.
That content does not get into the annex, so this is ok.
* Command.AddUrl when using a remote to download an url; this is new
content being added, so this is ok.
This commit was sponsored by Fernando Jimenez on Patreon.
This will be used to protect against CVE-2018-10859, where an encrypted
special remote is fed the wrong encrypted data, and so tricked into
decrypting something that the user encrypted with their gpg key and did
not store in git-annex.
It also protects against CVE-2018-10857, where a remote follows a http
redirect to a file:// url or to a local private web server. While that's
already been prevented in git-annex's own use of http, external special
remotes, hooks, etc use other http implementations and could still be
vulnerable.
The policy is not yet enforced, this commit only adds the appropriate
metadata to remotes.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
They're no worse than http certianly. And, the backport of these
security fixes has to deal with wget, which supports http https and ftp
and has no way to turn off individual schemes, so this will make that
easier.
A local http proxy would bypass the security configuration. So,
the security configuration has to be applied when choosing whether to
use the proxy.
While http rebinding attacks against the dns lookup of the proxy IP
address seem very unlikely, this implementation does prevent them, since
it resolves the IP address once, checks it, and then reconfigures
http-client's proxy using the resolved address.
This commit was sponsored by Ole-Morten Duesund on Patreon.
Security fix!
* git-annex will refuse to download content from http servers on
localhost, or any private IP addresses, to prevent accidental
exposure of internal data. This can be overridden with the
annex.security.allowed-http-addresses setting.
* Since curl's interface does not have a way to prevent it from accessing
localhost or private IP addresses, curl defaults to not being used
for url downloads, even if annex.web-options enabled it before.
Only when annex.security.allowed-http-addresses=all will curl be used.
Since S3 and WebDav use the Manager, the same policies apply to them too.
youtube-dl is not handled yet, and a http proxy configuration can bypass
these checks too. Those cases are still TBD.
This commit was sponsored by Jeff Goeke-Smith on Patreon.
Would be nice to add CIDR notation to this, but this is the minimal
thing needed for the security fix.
This commit was sponsored by Ewen McNeill on Patreon.
For use in a security boundary enforcement.
Based on https://en.wikipedia.org/wiki/Reserved_IP_addresses
Including supporting IPv4 addresses embedded in IPv6 addresses. Because
while RFC6052 3.1 says "Address translators MUST NOT translate packets
in which an address is composed of the Well-Known Prefix and a non-
global IPv4 address; they MUST drop these packets", I don't want to
trust that implementations get that right when enforcing a security
boundary.
This commit was sponsored by John Pellman on Patreon.
This is a clean way to add IP address restrictions to http-client, and
any library using it.
See https://github.com/snoyberg/http-client/issues/354#issuecomment-397830259
Some code from http-client and http-client-tls was copied in and
modified. Credited its author accordingly, and used the same MIT license.
The restrictions don't apply to http proxies. If using http proxies is a
problem, http-client already has a way to disable them.
SOCKS support is not included. As far as I can tell, http-client-tls
does not support SOCKS by default, and so git-annex never has.
The additional dependencies are free; git-annex already transitively
depended on them via http-conduit.
This commit was sponsored by Eric Drechsel on Patreon.
Security fix! Allowing any schemes, particularly file: and
possibly others like scp: allowed file exfiltration by anyone who had
write access to the git repository, since they could add an annexed file
using such an url, or using an url that redirected to such an url,
and wait for the victim to get it into their repository and send them a copy.
* Added annex.security.allowed-url-schemes setting, which defaults
to only allowing http and https URLs. Note especially that file:/
is no longer enabled by default.
* Removed annex.web-download-command, since its interface does not allow
supporting annex.security.allowed-url-schemes across redirects.
If you used this setting, you may want to instead use annex.web-options
to pass options to curl.
With annex.web-download-command removed, nearly all url accesses in
git-annex are made via Utility.Url via http-client or curl. http-client
only supports http and https, so no problem there.
(Disabling one and not the other is not implemented.)
Used curl --proto to limit the allowed url schemes.
Note that this will cause git annex fsck --from web to mark files using
a disallowed url scheme as not being present in the web. That seems
acceptable; fsck --from web also does that when a web server is not available.
youtube-dl already disabled file: itself (probably for similar
reasons). The scheme check was also added to youtube-dl urls for
completeness, although that check won't catch any redirects it might
follow. But youtube-dl goes off and does its own thing with other
protocols anyway, so that's fine.
Special remotes that support other domain-specific url schemes are not
affected by this change. In the bittorrent remote, aria2c can still
download magnet: links. The download of the .torrent file is
otherwise now limited by annex.security.allowed-url-schemes.
This does not address any external special remotes that might download
an url themselves. Current thinking is all external special remotes will
need to be audited for this problem, although many of them will use
http libraries that only support http and not curl's menagarie.
The related problem of accessing private localhost and LAN urls is not
addressed by this commit.
This commit was sponsored by Brett Eisenberg on Patreon.
