MFC r342227: bootpd: validate hardware type

Due to insufficient validation of network-provided data it may have been
possible for a malicious actor to craft a bootp packet which could cause
a stack buffer overflow.

admbugs: 850
Reported by: Reno Robert
Reviewed by: markj
Approved by: so
Security: FreeBSD-SA-18:15.bootpd
Sponsored by: The FreeBSD Foundation

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Spelling fixes for libexec/

Make tv_sec a time_t on all platforms but alpha. Brings us more in line with
POSIX. This also makes the struct correct we ever implement an i386-time64
architecture. Not that we need too.

Reviewed by: imp, brooks
Approved by: njl (acpica), des (no objects, touches procfs)
Tested with: make universe

Fix most cases where the address of an int is passed to a function expecting a
socklen_t * argument.

Add the '-h hostname' to usage(), too.
While I'm here, sync the usage() synopsis with the manual page synopsis:
make the [-i | -s] explicit and sort the options alphabetically.

Reminded by: ru
MFC after: 3 days

fix a couple typos in the comments

From NetBSD's bootpd (in src/usr.sbin/bootp)

fix bootpd to use fd_set. For some reason on Sparc, using int with
select is broken.

Add FBSDID. udp/bootps -> bootps/udp. Use err(3).

This code defined a private __P, nuke it.

Assume __STDC__, remove non-__STDC__ code.

Reviewed by: md5

Mark report() as printflike and fix resulting warnings, including one bug
(get_errmsg -> get_errmsg())

RFC2132 is not clear about whether the "Maximum DHCP Message Size"
refers to the size of the whole ethernet packet, just the DHCP
message within the UDP payload, or something else. bootpd interpreted
it as a maximum UDP payload size, so it could end up sending
fragmented packets to clients (such as some versions of Etherboot)
that used different interpretations of the maximum message size.

Switch to the most conservative interpretation: ensure that the
ethernet packet containing the response is no larger than the
specified maximum message size. This matches the behaviour of
the ISC dhcpd.

MFC after: 1 week

Add `_PATH_DEVZERO'.
Use _PATH_* where where possible.

$Id$ -> $FreeBSD$

More egcs warning fixes:
o main returns int not void
o use return 0 at end of main when needed
o use braces to avoid potentially ambiguous else
o don't default to type int (and also remove a useless register
modifier).

Reviewed by: obrien and chuckr

Ensure that things returned by gethostname() and
friends are terminated and allow for a maximum
host name length of MAXHOSTNAMELEN - 1.
Put parenthesis around sizeof args.
Make some variables static.
Fix telnetd -u (broken by my last commit)

Prompted by: bde

Block for buffer overflow.

PR: bin/9031

Changed unbounded strcpy() to snprintf() to fix buffer overrun exploit

Use gethostname(3) to obtain the local host name, as opposed to uname(3).
Otherwise the length of the name is limited to 32 characters only.

Don't rely on stderr to report bad news.

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

add forgotten $Id$

Fix conflicts from 2.4.3 merge

Remove trailing whitespace.

This commit was generated by cvs2svn to compensate for changes in r3229,
which included commits to RCS files with non-trunk default branches.

Rearrange bootpd