Date: Mon, 13 May 2002 19:58:57 +0300 From: Peter Pentchev <roam@ringlet.net> To: Sam Leffler <sam@errno.com> Cc: "Carroll, D. (Danny)" <Danny.Carroll@mail.ing.nl>, Mitch Collinsworth <mitch@ccmr.cornell.edu>, security@FreeBSD.ORG Subject: Re: DHCPD bug Message-ID: <20020513195857.J34169@straylight.oblivion.bg> In-Reply-To: <007201c1fa96$7f8a6820$38036a83@ZABU>; from sam@errno.com on Mon, May 13, 2002 at 08:54:35AM -0700 References: <6C506EA550443D44A061432F1E92EA4C6C5156@ing.com> <007201c1fa96$7f8a6820$38036a83@ZABU>
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On Mon, May 13, 2002 at 08:54:35AM -0700, Sam Leffler wrote:
> > But my point is, maybe a simple sed or perl script ran over the source
> > might yeild other potential problems?
>=20
> NetBSD used gcc -Wformat <mumble> (or whatever it is) to validate format
> strings against the varags parameter lists.
So does FreeBSD, for the base system, if FORMAT_AUDIT is defined
in the Makefile - -Wnon-const-format and -Wno-format-extra-args
are added to CFLAGS, making gcc whine for the case of syslog(var)
and syslog("%s %s", var), respectively.
For the ports, though - I have tried exorcising the compiler
warnings from a couple of largish ports that I maintain, nothing
to compare with the size of KDE, GNOME, GCC, or even ISC-DHCP,
and let me tell you, it is no fun, no fun at all.. A little
make(1) output postprocessor (or a simple fgrep run over
the make(1) output) could help things, if you are only looking
for format string misuse, but even then, it may not help a whole
lot - the two format warnings added to gcc only analyze calls
to functions that have been explicitly defined as being printf-like,
and most programs out there roll out their own logging functions,
few (very few) of which are marked as such.
So basically, yes, it could be done; no, I would not expect each
and every port maintainer to try for it. Come to think of it,
I myself have not tried for it until now; this might change,
but then again, I maintain neither the largest nor the most important
ports, so it might be feasible for me, but not for others.
G'luck,
Peter
--=20
Peter Pentchev roam@ringlet.net roam@FreeBSD.org
PGP key: http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553
Thit sentence is not self-referential because "thit" is not a word.
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