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xen/privcmd: fix integer truncation in IOCTL_PRIVCMD_MMAPBATCH

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The size field in the XENMEM_add_to_physmap_range is an uint16_t, and the
privcmd driver was doing an implicit truncation of an int into an uint16_t
when filling the hypercall parameters.

Fix this by adding a loop and making sure privcmd splits ioctl request into
2^16 chunks when issuing the hypercalls.

Reported and tested by:	Marcin Cieslak <saper@saper.info>
Sponsored by:		Citrix Systems R&D
This commit is contained in:
Roger Pau Monné 2016-05-06 16:44:46 +00:00
parent 03f5b58d56
commit 288b2385b8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=299185
1 changed files with 57 additions and 37 deletions
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94
sys/dev/xen/privcmd/privcmd.c
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@ -45,6 +45,7 @@ __FBSDID("$FreeBSD$");
#include <sys/tree.h>
#include <sys/module.h>
#include <sys/proc.h>
#include <sys/bitset.h>
#include <vm/vm.h>
#include <vm/vm_param.h>
@ -72,7 +73,7 @@ struct privcmd_map {
int pseudo_phys_res_id;
vm_paddr_t phys_base_addr;
boolean_t mapped;
int *errs;
BITSET_DEFINE_VAR() *err;
};
static d_ioctl_t privcmd_ioctl;
@ -138,7 +139,7 @@ privcmd_pg_dtor(void *handle)
rm.gpfn = atop(map->phys_base_addr) + i;
HYPERVISOR_memory_op(XENMEM_remove_from_physmap, &rm);
}
free(map->errs, M_PRIVCMD);
free(map->err, M_PRIVCMD);
}
error = xenmem_free(privcmd_dev, map->pseudo_phys_res_id,
@ -160,7 +161,7 @@ privcmd_pg_fault(vm_object_t object, vm_ooffset_t offset,
return (VM_PAGER_FAIL);
pidx = OFF_TO_IDX(offset);
if (pidx >= map->size || map->errs[pidx] != 0)
if (pidx >= map->size || BIT_ISSET(map->size, pidx, map->err))
return (VM_PAGER_FAIL);
page = PHYS_TO_VM_PAGE(map->phys_base_addr + offset);
@ -249,14 +250,15 @@ privcmd_ioctl(struct cdev *dev, unsigned long cmd, caddr_t arg,
vm_map_t map;
vm_map_entry_t entry;
vm_object_t mem;
vm_pindex_t index;
vm_pindex_t pindex;
vm_prot_t prot;
boolean_t wired;
struct xen_add_to_physmap_range add;
xen_ulong_t *idxs;
xen_pfn_t *gpfns;
int *errs;
int *errs, index;
struct privcmd_map *umap;
uint16_t num;
mmap = (struct ioctl_privcmd_mmapbatch *)arg;
@ -268,7 +270,7 @@ privcmd_ioctl(struct cdev *dev, unsigned long cmd, caddr_t arg,
map = &td->td_proc->p_vmspace->vm_map;
error = vm_map_lookup(&map, mmap->addr, VM_PROT_NONE, &entry,
&mem, &index, &prot, &wired);
&mem, &pindex, &prot, &wired);
if (error != KERN_SUCCESS) {
error = EINVAL;
break;
@ -289,54 +291,72 @@ privcmd_ioctl(struct cdev *dev, unsigned long cmd, caddr_t arg,
add.domid = DOMID_SELF;
add.space = XENMAPSPACE_gmfn_foreign;
add.size = mmap->num;
add.foreign_domid = mmap->dom;
idxs = malloc(sizeof(*idxs) * mmap->num, M_PRIVCMD,
M_WAITOK | M_ZERO);
gpfns = malloc(sizeof(*gpfns) * mmap->num, M_PRIVCMD,
M_WAITOK | M_ZERO);
errs = malloc(sizeof(*errs) * mmap->num, M_PRIVCMD,
M_WAITOK | M_ZERO);
/*
* The 'size' field in the xen_add_to_physmap_range only
* allows for UINT16_MAX mappings in a single hypercall.
*/
num = MIN(mmap->num, UINT16_MAX);
idxs = malloc(sizeof(*idxs) * num, M_PRIVCMD, M_WAITOK);
gpfns = malloc(sizeof(*gpfns) * num, M_PRIVCMD, M_WAITOK);
errs = malloc(sizeof(*errs) * num, M_PRIVCMD, M_WAITOK);
set_xen_guest_handle(add.idxs, idxs);
set_xen_guest_handle(add.gpfns, gpfns);
set_xen_guest_handle(add.errs, errs);
error = copyin(&mmap->arr[0], idxs,
sizeof(idxs[0]) * mmap->num);
if (error != 0)
goto mmap_out;
/* Allocate a bitset to store broken page mappings. */
umap->err = BITSET_ALLOC(mmap->num, M_PRIVCMD,
M_WAITOK | M_ZERO);
for (i = 0; i < mmap->num; i++)
gpfns[i] = atop(umap->phys_base_addr + i * PAGE_SIZE);
for (index = 0; index < mmap->num; index += num) {
num = MIN(mmap->num - index, UINT16_MAX);
add.size = num;
error = HYPERVISOR_memory_op(XENMEM_add_to_physmap_range, &add);
if (error) {
error = xen_translate_error(error);
goto mmap_out;
error = copyin(&mmap->arr[index], idxs,
sizeof(idxs[0]) * num);
if (error != 0)
goto mmap_out;
for (i = 0; i < num; i++)
gpfns[i] = atop(umap->phys_base_addr +
(i + index) * PAGE_SIZE);
bzero(errs, sizeof(*errs) * num);
error = HYPERVISOR_memory_op(
XENMEM_add_to_physmap_range, &add);
if (error != 0) {
error = xen_translate_error(error);
goto mmap_out;
}
for (i = 0; i < num; i++) {
if (errs[i] != 0) {
errs[i] = xen_translate_error(errs[i]);
/* Mark the page as invalid. */
BIT_SET(mmap->num, index + i,
umap->err);
}
}
error = copyout(errs, &mmap->err[index],
sizeof(errs[0]) * num);
if (error != 0)
goto mmap_out;
}
for (i = 0; i < mmap->num; i++) {
if (errs[i] != 0)
errs[i] = xen_translate_error(errs[i]);
}
/*
* Save errs, so we know which pages have been
* successfully mapped.
*/
umap->errs = errs;
umap->mapped = true;
error = copyout(errs, &mmap->err[0],
sizeof(errs[0]) * mmap->num);
mmap_out:
free(idxs, M_PRIVCMD);
free(gpfns, M_PRIVCMD);
free(errs, M_PRIVCMD);
if (!umap->mapped)
free(errs, M_PRIVCMD);
free(umap->err, M_PRIVCMD);
break;
}