Date: Thu, 19 Jul 2001 21:59:57 +0300 From: Ruslan Ermilov <ru@FreeBSD.org> To: Matt Dillon <dillon@earth.backplane.com> Cc: Assar Westerlund <assar@FreeBSD.org>, security@FreeBSD.org Subject: Re: [PATCH] Re: FreeBSD remote root exploit ? Message-ID: <20010719215957.A74024@sunbay.com> In-Reply-To: <200107191817.f6JIHSJ76262@earth.backplane.com>; from dillon@earth.backplane.com on Thu, Jul 19, 2001 at 11:17:28AM -0700 References: <5.1.0.14.0.20010719001357.03e22638@192.168.0.12> <014d01c11031$bdab5a10$2001a8c0@clitoris> <20010719201407.B61061@sunbay.com> <003701c11077$b3125400$0d00a8c0@alexus> <3B5718A0.2B650C9C@oksala.org> <200107191752.f6JHqer75736@earth.backplane.com> <20010719205948.D67829@sunbay.com> <200107191817.f6JIHSJ76262@earth.backplane.com>
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On Thu, Jul 19, 2001 at 11:17:28AM -0700, Matt Dillon wrote:
>
> :> the ENCRYPT code) where this is true. This patch will fix the existing
> :> options-based hole, but doesn't close it.
> :>
> :Doesn't this handle this?
> :
> :int
> :output_data(const char *format, ...)
> :{
> : va_list args;
> : size_t remaining, ret;
> : va_start(args, format);
> : remaining = BUFSIZ - (nfrontp - netobuf);
> : /* try a netflush() if the room is too low */
> : if (strlen(format) > remaining || BUFSIZ / 4 > remaining) {
> : ^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> Nope. What if the format is "%d" and the number is "123"? Or
> that format is "%s" and the argument is "abcdefghijklmnopqrstuvwxyz"?
> Then strlen(format) could be < remaining but the result of the vsnprintf()
> could still be > remaining.
>
> The output_data() calls for the various options are safe, strlen(format)
> will always be larger then the actual formatted result. But the
> debugging and crypto calls to output_data() are not safe.
>
> -Matt
>
> : netflush();
> : remaining = BUFSIZ - (nfrontp - netobuf);
> : }
> : ret = vsnprintf(nfrontp, remaining, format, args);
>
Should be fixed in state.c,v 1.7. Thanks, Assar!
Cheers,
--
Ruslan Ermilov Oracle Developer/DBA,
ru@sunbay.com Sunbay Software AG,
ru@FreeBSD.org FreeBSD committer,
+380.652.512.251 Simferopol, Ukraine
http://www.FreeBSD.org The Power To Serve
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