Sendmail, 3rd Edition

Bogus qf Files

For security reasons, V8 sendmail performs a number of checks on each qf file before trusting its contents. If any qf file fails to be trustworthy, sendmail converts the leading q in its name to an uppercase Q.^[8] We discuss each possible problem in the sections that follow.

Note that when sendmail renames a qf file into a Qf file, it logs that it did so. In the following, qffile is the full path and filename of the qf file, before it was renamed:

Losing qffile: reasonhere 

Also note that, although sendmail checks the qf file for a number of plausible errors, its checking is by no means exhaustive. The checks we describe here are no substitute for a well-managed system.

Badly Formed qf Filename

V8.6 sendmail always checks the form of the qf filename for correctness. V8.7 through V8.9 sendmail also check the qf filename but do so only if PICKY_QF_NAME_CHECK is defined when building sendmail (PICKY_HELO_CHECK). V8.10 and above no longer check the form of the qf filename for correctness.

Prior to V8.10, if the qf filename is incorrectly formed (Section 11.2.1), sendmail presumes that some other program placed the file in the queue and rejects it:

orderq: bogus qf name bogus namehere

For V8.7 through V8.9, sendmail made this check only if PICKY_QF_NAME_CHECK was defined when building sendmail. This was introduced because some sites allow legitimate programs (other than sendmail) to write into sendmail’s queue. To fix this problem, either undefine PICKY_QF_NAME_CHECK when ...