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Date: Mon, 12 May 2008 11:56:43 +0800
From: WANG Cong <xiyou.wangcong@gmail.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: WANG Cong <xiyou.wangcong@gmail.com>, LKML <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@osdl.org>, WANG Cong <wangcong@zeuux.org>
Subject: Re: [Patch 7/9] fs/exec.c: fix wrong return value of
	prepare_binprm()
Message-ID: <20080512035643.GE2572@hacking>
References: <1210254754206-git-send-email-xiyou.wangcong@gmail.com> <12102548553947-git-send-email-xiyou.wangcong@gmail.com> <20080510193105.GG13907@ZenIV.linux.org.uk>
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On Sat, May 10, 2008 at 08:31:05PM +0100, Al Viro wrote:
>On Thu, May 08, 2008 at 09:52:32PM +0800, WANG Cong wrote:
>> All prepare_binprm()'s callers assume that prepare_binprm() fails
>> when it returns negative. However, prepare_binprm() most probably returns
>> the return value of kernel_read(), which may return positive on failure!
>> 
>> Thus this should be fixed.
>
>Since when does read return positive on failure?

When an EIO occurs, I think. For example,

        retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
                             (char *)elf_phdata,size);
        error = -EIO;
        if (retval != size) {
                if (retval < 0)
                        error = retval;
                goto out_close;
        }


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