Messages in this thread | | | Date | Sat, 15 Mar 2008 18:00:58 -0400 | From | Alexander Viro <> | Subject | Re: [RFC] correct flags to f_mode conversion in __dentry_open |
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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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