c51cd5fe91
Before safecopies, the IO_ENDPT and DL_ENDPT message fields were needed to know which actual process to copy data from/to, as that process may not always be the caller. Now that we have full safecopy support, these fields have become useless for that purpose: the owner of the grant is *always* the caller. Allowing the caller to supply another endpoint is in fact dangerous, because the callee may then end up using a grant from a third party. One could call this a variant of the confused deputy problem. From now on, safecopy calls should always use the caller's endpoint as grant owner. This fully obsoletes the DL_ENDPT field in the inet/ethernet protocol. IO_ENDPT has other uses besides identifying the grant owner though. This patch renames IO_ENDPT to USER_ENDPT, not only because that is a more fitting name (it should never be used for I/O after all), but also in order to intentionally break any old system source code outside the base system. If this patch breaks your code, fixing it is fairly simple: - DL_ENDPT should be replaced with m_source; - IO_ENDPT should be replaced with m_source when used for safecopies; - IO_ENDPT should be replaced with USER_ENDPT for any other use, e.g. when setting REP_ENDPT, matching requests in CANCEL calls, getting DEV_SELECT flags, and retrieving of the real user process's endpoint in DEV_OPEN. The changes in this patch are binary backward compatible.
37 lines
908 B
C
37 lines
908 B
C
/* The system call implemented in this file:
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* m_type: SYS_IOPENABLE
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*
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* The parameters for this system call are:
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* m2_i2: IOP_ENDPT (process to give I/O Protection Level bits)
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*
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* Author:
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* Jorrit N. Herder <jnherder@cs.vu.nl>
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*/
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#include "kernel/system.h"
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#include "kernel/kernel.h"
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#include <minix/endpoint.h>
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#include "arch_proto.h"
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/*===========================================================================*
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* do_iopenable *
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*===========================================================================*/
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PUBLIC int do_iopenable(struct proc * caller, message * m_ptr)
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{
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int proc_nr;
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#if 1 /* ENABLE_USERPRIV && ENABLE_USERIOPL */
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if (m_ptr->IOP_ENDPT == SELF) {
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proc_nr = _ENDPOINT_P(caller->p_endpoint);
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} else if(!isokendpt(m_ptr->IOP_ENDPT, &proc_nr))
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return(EINVAL);
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enable_iop(proc_addr(proc_nr));
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return(OK);
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#else
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return(EPERM);
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#endif
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}
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