linux-kernel - core dumping on NFS mounted directory

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Date:	Mon, 14 Jun 2010 11:05:53 -0700
From:	Lei Sun <leisun124@...il.com>
To:	linux-kernel@...r.kernel.org
Subject: core dumping on NFS mounted directory

Hi :
   In 2.6.3x, I am logging in as a root and running app from NFS
mounted directory. The app crashed with 0 bytes core file (I have set
"ulimit -c unlimited", so it's not an issue).
The following code in fs/exec.c is causing this:

    /*
     * Dont allow local users get cute and trick others to coredump
     * into their pre-created files:
     * Note, this is not relevant for pipes
     */
    if (!ispipe && (inode->i_uid != current_fsuid()))
        goto close_fail;

What is the intention of above piece of code?  If it's security
concern,  it clearly break the NFS mounted (different uid) core
dumping logic.

Thanks
lei
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