svn rev #20304: trunk/src/lib/krb5/krb/

[raeburn@MIT.EDU]

Commit By: raeburn
Log Message: 
ticket: new
subject: fix possible buffer overrun in handling generic-error return
target_version: 1.6.5
tags: pullup

Jeff Altman reported this, based on a crash seen in KfW in the wild.

The krb5_data handle used to describe the message field returned by the KDC is
not null-terminated, but we use a "%s" format to incorporate it into an error
message string.  In the right circumstances, garbage bytes can be pulled into
the string, or a memory fault may result.

However, as this is in the error-reporting part of the client-side code for
fetching new credentials, it's a relatively minor DoS attack only, not a
serious security exposure.  Should be fixed in the next releases, though.



Changed Files:
U   trunk/src/lib/krb5/krb/gc_via_tkt.c