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Kernel: add support for indirect grants

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This commit is contained in:
David van Moolenbroek
2009-11-02 22:30:37 +00:00
parent 769bed22c8
commit f814fe41be
3 changed files with 79 additions and 73 deletions
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120
kernel/system/do_safecopy.c
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@@ -20,6 +20,8 @@
#include "../system.h"
#include "../vm.h"
#define MAX_INDIRECT_DEPTH 5 /* up to how many indirect grants to follow? */
#define MEM_TOP 0xFFFFFFFFUL
FORWARD _PROTOTYPE(int safecopy, (endpoint_t, endpoint_t, cp_grant_id_t, int, int, size_t, vir_bytes, vir_bytes, int));
@@ -43,51 +45,87 @@ endpoint_t *e_granter; /* new granter (magic grants) */
static cp_grant_t g;
static int proc_nr;
static struct proc *granter_proc;
int r;
int r, depth = 0;
/* Get granter process slot (if valid), and check range of
* grant id.
*/
if(!isokendpt(granter, &proc_nr) || !GRANT_VALID(grant)) {
kprintf("grant verify failed: invalid granter or grant\n");
return(EINVAL);
}
granter_proc = proc_addr(proc_nr);
/* If there is no priv. structure, or no grant table in the
* priv. structure, or the grant table in the priv. structure
* is too small for the grant, return EPERM.
*/
if(!HASGRANTTABLE(granter_proc)) return EPERM;
if(priv(granter_proc)->s_grant_entries <= grant) {
do {
/* Get granter process slot (if valid), and check range of
* grant id.
*/
if(!isokendpt(granter, &proc_nr) || !GRANT_VALID(grant)) {
kprintf(
"verify_grant: grant verify failed in ep %d proc %d: "
"grant %d out of range for table size %d\n",
granter, proc_nr, grant,
priv(granter_proc)->s_grant_entries);
return(EPERM);
}
"grant verify failed: invalid granter or grant\n");
return(EINVAL);
}
granter_proc = proc_addr(proc_nr);
/* Copy the grant entry corresponding to this id to see what it
* looks like. If it fails, hide the fact that granter has
* (presumably) set an invalid grant table entry by returning
* EPERM, just like with an invalid grant id.
*/
if((r=data_copy(granter,
priv(granter_proc)->s_grant_table + sizeof(g)*grant,
SYSTEM, (vir_bytes) &g, sizeof(g))) != OK) {
kprintf("verify_grant: grant verify: data_copy failed\n");
return EPERM;
}
/* If there is no priv. structure, or no grant table in the
* priv. structure, or the grant table in the priv. structure
* is too small for the grant, return EPERM.
*/
if(!HASGRANTTABLE(granter_proc)) return EPERM;
/* Check validity. */
if((g.cp_flags & (CPF_USED | CPF_VALID)) != (CPF_USED | CPF_VALID)) {
kprintf(
"verify_grant: grant failed: invalid (%d flags 0x%lx)\n",
grant, g.cp_flags);
return EPERM;
}
if(priv(granter_proc)->s_grant_entries <= grant) {
kprintf(
"verify_grant: grant verify failed in ep %d "
"proc %d: grant %d out of range "
"for table size %d\n",
granter, proc_nr, grant,
priv(granter_proc)->s_grant_entries);
return(EPERM);
}
/* Copy the grant entry corresponding to this id to see what it
* looks like. If it fails, hide the fact that granter has
* (presumably) set an invalid grant table entry by returning
* EPERM, just like with an invalid grant id.
*/
if((r=data_copy(granter,
priv(granter_proc)->s_grant_table + sizeof(g)*grant,
SYSTEM, (vir_bytes) &g, sizeof(g))) != OK) {
kprintf(
"verify_grant: grant verify: data_copy failed\n");
return EPERM;
}
/* Check validity. */
if((g.cp_flags & (CPF_USED | CPF_VALID)) !=
(CPF_USED | CPF_VALID)) {
kprintf(
"verify_grant: grant failed: invalid (%d flags 0x%lx)\n",
grant, g.cp_flags);
return EPERM;
}
/* The given grant may be an indirect grant, that is, a grant
* that provides permission to use a grant given to the
* granter (i.e., for which it is the grantee). This can lead
* to a chain of indirect grants which must be followed back.
*/
if((g.cp_flags & CPF_INDIRECT)) {
/* Stop after a few iterations. There may be a loop. */
if (depth == MAX_INDIRECT_DEPTH) {
kprintf(
"verify grant: indirect grant verify "
"failed: exceeded maximum depth\n");
return ELOOP;
}
depth++;
/* Verify actual grantee. */
if(g.cp_u.cp_indirect.cp_who_to != grantee &&
grantee != ANY) {
kprintf(
"verify_grant: indirect grant verify "
"failed: bad grantee\n");
return EPERM;
}
/* Start over with new granter, grant, and grantee. */
grantee = granter;
granter = g.cp_u.cp_indirect.cp_who_from;
grant = g.cp_u.cp_indirect.cp_grant;
}
} while(g.cp_flags & CPF_INDIRECT);
/* Check access of grant. */
if(((g.cp_flags & access) != access)) {