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points by JdeBP 2 days ago | 0 comments

I suggest finding a code path where FreeBSD crypt() ever returns NULL, which would mean one of its internal functions returning non-zero, before getting too excited. They all end in return (0) . (-:

* https://cgit.freebsd.org/src/tree/lib/libcrypt

As I said, the callers of crypt() have for a long time been using the knowledge that crypt() on their platform simply never returns NULL. Unix has never been returning NULL from crypt() as far back as 7th Edition, when it simply always returned a pointer to a single internal static buffer.

* https://github.com/dspinellis/unix-history-repo/blob/Researc...

The reality is that all C library people have to work with a corpus of Unix applications that do not check for crypt() returning NULL that goes back almost 50 years, and an error return mechanism that barely exists outwith the pages of the SUS.

That includes callers in single-user mode in process 1 in some configurations.

* https://cvsweb.netbsd.org/bsdweb.cgi/src/sbin/init/init.c?an...

[–] ruslan 2 days ago

Well, crypt_blowfish() has a number of returns with (-1). I'm not familiar with Blowfish, so it's hard for me to trace the possibility of failure here. But what if in a distant future someone adds more hashing algorithms to the list without possessing historical knowledge of this "never return not 0" ?

* https://cgit.freebsd.org/src/tree/secure/lib/libcrypt/crypt-...

Failing to check result of crypt() in init cannot do much harm, doing so is equivalent of going system reboot (crash init :-)). Besides, whoever has access to system console can do whatever they want with the system, no password can prevent from that.

[–] JdeBP 2 days ago

I have no doubt, despite that Marshall Kirk McKusick is still committing in 2026, that FreeBSD developers will come along that do not know history. But they will get pointed to the manual page that (amusingly) says that returning NULL is 'not a standard behaviour' and that AT&T Unix never did that.

* https://man.freebsd.org/cgi/man.cgi?query=crypt&sektion=3&fo...

NetBSD's manual is more detailed on the subject, and explains the bind that library implementors have been in for decades, thanks to almost 50 years of applications knowing what crypt() 'really' does.

* https://man.netbsd.org/crypt.3#RETURN%20VALUES

And this despite the SUS trying to shoehorn an error return mechanism into crypt(3) in order to accommodate the problems that operating systems had exporting encryption code, two decades afterwards. (The 1997 GoSolo book explains that this is why there's an ENOSYS error.)