cURL and libcurl, Network, Security

curl 7.40.0: unix domain sockets and smb

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curl and libcurl curl dot-to-dot7.40.0 was just released this morning. There’s a closer look at some of the perhaps more noteworthy changes. As usual, you can find the entire changelog on the curl web site.

HTTP over unix domain sockets

So just before the feature window closed for the pending 7.40.0 release of curl, Peter Wu’s patch series was merged that brings the ability to curl and libcurl to do HTTP over unix domain sockets. This is a feature that’s been mentioned many times through the history of curl but never previously truly implemented. Peter also very nicely adjusted the test server and made two test cases that verify the functionality.

To use this with the curl command line, you specify the socket path to the new –unix-domain option and assuming your local HTTP server listens on that socket, you’ll get the response back just as with an ordinary TCP connection.

Doing the operation from libcurl means using the new CURLOPT_UNIX_SOCKET_PATH option.

This feature is actually not limited to HTTP, you can do all the TCP-based protocols except FTP over the unix domain socket, but it is to my knowledge only HTTP that is regularly used this way. The reason FTP isn’t supported is of course its use of two connections which would be even weirder to do like this.

SMB

SMB is also known as CIFS and is an old network protocol from the Microsoft world access files. curl and libcurl now support this protocol with SMB:// URLs thanks to work by Bill Nagel and Steve Holme.

Security Advisories

Last year we had a large amount of security advisories published (eight to be precise), and this year we start out with two fresh ones already on the 8th day… The ones this time were of course discovered and researched already last year.

CVE-2014-8151 is a way we accidentally allowed an application to bypass the TLS server certificate check if a TLS Session-ID was already cached for a non-checked session – when using the Mac OS SecureTransport SSL backend.

CVE-2014-8150 is a URL request injection. When letting curl or libcurl speak over a HTTP proxy, it would copy the URL verbatim into the HTTP request going to the proxy, which means that if you craft the URL and insert CRLFs (carriage returns and linefeed characters) you can insert your own second request or even custom headers into the request that goes to the proxy.

You may enjoy taking a look at the curl vulnerabilities table.

Bugs bugs bugs

The release notes mention no less than 120 specific bug fixes, which in comparison to other releases is more than average.

Enjoy!

2 thoughts on “curl 7.40.0: unix domain sockets and smb”

  2. Passive FTP could certainly in theory be made to work over unix socket, but since it still requires a second connection for the data I figure a typical such FTP server would listen to two such sockets and curl only uses a single one.

    I’m not aware of any existing FTP server software that supports this.

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