Date: Fri, 19 Oct 2001 16:32:49 +0300 From: Peter Pentchev <roam@ringlet.net> To: Tomek <tomek@mpionline.com> Cc: freebsd-security@FreeBSD.ORG Subject: Re: Whats to stop one user from being root? Message-ID: <20011019163248.C1416@straylight.oblivion.bg> In-Reply-To: <001101c158a1$d12ab320$f6f073d1@mpionline.com>; from tomek@mpionline.com on Fri, Oct 19, 2001 at 07:27:36AM -0600 References: <001101c158a1$d12ab320$f6f073d1@mpionline.com>
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On Fri, Oct 19, 2001 at 07:27:36AM -0600, Tomek wrote: > Hey there, > I have 2 questions really, maybe they are obvious, maybe not. > > 1. What is to stop a user program from calling half way in the middle of > "chmod" for example and bypassing any security checking code? I know > this would be highly depending on kernal version, but is there > protection against this? System calls are not done as calls directly into the kernel, by address. It's more like you execute a specified system call by number (a small integer, usually less than 512), then the address is looked up in a kernel array. The userland program has no control over this kernel array, so it does not really have any way to specify the exact address in kernel code to jump to. G'luck, Peter -- I am not the subject of this sentence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-security" in the body of the message
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