freebsd-dev

History

Gleb Smirnoff ca573c9a17 sshd: update the libwrap patch to drop connections early OpenSSH has dropped libwrap support in OpenSSH 6.7p in 2014 (f2719b7c in github.com/openssh/openssh-portable) and we maintain the patch ourselves since 2016 (`a0ee8cc636`). Over the years, the libwrap support has deteriotated and probably that was reason for removal upstream. Original idea of libwrap was to drop illegitimate connection as soon as possible, but over the years the code was pushed further down and down and ended in the forked client connection handler. The negative effects of late dropping is increasing attack surface for hosts that are to be dropped anyway. Apart from hypothetical future vulnerabilities in connection handling, today a malicious host listed in /etc/hosts.allow still can trigger sshd to enter connection throttling mode, which is enabled by default (see MaxStartups in sshd_config(5)), effectively casting DoS attack. Note that on OpenBSD this attack isn't possible, since they enable MaxStartups together with UseBlacklist. A only negative effect from early drop, that I can imagine, is that now main listener parses file in /etc, and if our root filesystems goes bad, it would get stuck. But unlikely you'd be able to login in that case anyway. Implementation details: - For brevity we reuse the same struct request_info. This isn't a documented feature of libwrap, but code review, viewing data in a debugger and real life testing shows that if we clear RQ_CLIENT_NAME and RQ_CLIENT_ADDR every time, it works as intended. - We set SO_LINGER on the socket to force immediate connection reset. - We log message exactly as libwrap's refuse() would do. Differential revision: https://reviews.freebsd.org/D33044		2022-01-02 18:32:30 -08:00
..
heimdal	kerberos.8: Replace dead link	2021-05-16 01:37:09 -04:00
openssh	sshd: update the libwrap patch to drop connections early	2022-01-02 18:32:30 -08:00
openssl	OpenSSL: Merge OpenSSL 1.1.1m	2021-12-14 16:03:52 -05:00
README

README

$FreeBSD$

This directory is for the EXACT same use as src/contrib, except it
holds crypto sources.  In other words, this holds raw sources obtained
from various third party vendors, with FreeBSD patches applied.  No
compilation is done from this directory, it is all done from the
src/secure directory.  The separation between src/contrib and src/crypto
is the result of an old USA law, which made these sources export
controlled, so they had to be kept separate.