(RHSA-2010:0221) Low: squid security and bug fix update

Squid is a high-performance proxy caching server for web clients,
supporting FTP, Gopher, and HTTP data objects.

A flaw was found in the way Squid processed certain external ACL helper
HTTP header fields that contained a delimiter that was not a comma. A
remote attacker could issue a crafted request to the Squid server, causing
excessive CPU use (up to 100%). (CVE-2009-2855)

Note: The CVE-2009-2855 issue only affected non-default configurations that
use an external ACL helper script.

A flaw was found in the way Squid handled truncated DNS replies. A remote
attacker able to send specially-crafted UDP packets to Squid’s DNS client
port could trigger an assertion failure in Squid’s child process, causing
that child process to exit. (CVE-2010-0308)

This update also fixes the following bugs:

• Squid’s init script returns a non-zero value when trying to stop a
  stopped service. This is not LSB compliant and can generate difficulties in
  cluster environments. This update makes stopping LSB compliant. (BZ#521926)

• Squid is not currently built to support MAC address filtering in ACLs.
  This update includes support for MAC address filtering. (BZ#496170)

• Squid is not currently built to support Kerberos negotiate
  authentication. This update enables Kerberos authentication. (BZ#516245)

• Squid does not include the port number as part of URIs it constructs when
  configured as an accelerator. This results in a 403 error. This update
  corrects this behavior. (BZ#538738)

• the error_map feature does not work if the same handling is set also on
  the HTTP server that operates in deflate mode. This update fixes this
  issue. (BZ#470843)

All users of squid should upgrade to this updated package, which resolves
these issues. After installing this update, the squid service will be
restarted automatically.