[krbdev.mit.edu #1235] Bug in gss_krb5_ccache_name

[Ben Cox via RT]

Hello,

The attached unified diff against the krb5-1.2.6 source tree fixes a bug
in gss_krb5_ccache_name returns a string that has been freed.

The gss_krb5_ccache_name function has an "out_name" parameter that is
supposed to give the old value of the default ccache name. 
Unfortunately, before control returns to the caller,
gss_krb5_ccache_name calls krb5_cc_set_default_name, which frees the
buffer that has just been pointed to by *out_name.

The attached patch fixes gss_krb5_ccache_name to strdup the string
before returning (and return GSS_S_FAILURE if the strdup fails).  It
also fixes the only caller of gss_krb5_ccache_name (that I could find in
the source tree), which was strdup'ing the result, not to strdup it
anymore.

Thanks,

-- Ben Cox