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    SubjectRe: [RFC] correct flags to f_mode conversion in __dentry_open
    On Sat, Mar 15, 2008 at 05:59:52PM -0400, Alan Cox wrote:
    > On Wed, Mar 12, 2008 at 02:25:27PM -0400, Eric Paris wrote:
    > > I recently tried to add an SELinux BUG_ON in the case where the kernel
    > > made a permission request for no permissions and was able to stumble
    > > over it with something as simple as
    > >
    > > open("/dev/null", 3);
    > >
    > > Notice that 3 == (O_RDWR | O_WRONLY)
    > >
    > > First question, is 3 ever a valid flag from from userspace to sys_open?
    >
    > Yes.
    >
    > > does 11 really mean and should it really always be mapped to (FMODE_READ
    > > | FMODE_WRITE) or should it continue to get mapped to 'no permission?'
    >
    > We've always mapped 3 to "no permission" to read or write. It's a linuxism

    Note that we *do* request MAY_READ|MAY_WRITE; "no permission" part is
    about what you can do to resulting descriptor afterwards.


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