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Add a helper function for validating VA ranges.

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Functions which take untrusted user ranges must validate against the
bounds of the map, and also check for wraparound.  Instead of having the
same logic duplicated in a number of places, add a function to check.

Reviewed by:	dougm, kib
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D25328
This commit is contained in:
Mark Johnston 2020-06-19 03:32:04 +00:00
parent 61b006887e
commit 0f1e6ec591
5 changed files with 25 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
sys/compat/linuxkpi/common/src/linux_page.c
View File

@ -222,7 +222,7 @@ __get_user_pages_fast(unsigned long start, int nr_pages, int write,
va = start;
map = &curthread->td_proc->p_vmspace->vm_map;
end = start + (((size_t)nr_pages) << PAGE_SHIFT);
if (start < vm_map_min(map) || end > vm_map_max(map))
if (!vm_map_range_valid(map, start, end))
return (-EINVAL);
prot = write ? (VM_PROT_READ | VM_PROT_WRITE) : VM_PROT_READ;
for (count = 0, mp = pages, va = start; va < end;

5
sys/vm/vm_fault.c
View File

@ -1713,10 +1713,7 @@ vm_fault_quick_hold_pages(vm_map_t map, vm_offset_t addr, vm_size_t len,
end = round_page(addr + len);
addr = trunc_page(addr);
/*
* Check for illegal addresses.
*/
if (addr < vm_map_min(map) || addr > end || end > vm_map_max(map))
if (!vm_map_range_valid(map, addr, end))
return (-1);
if (atop(end - addr) > max_count)

12
sys/vm/vm_map.c
View File

@ -1616,8 +1616,7 @@ vm_map_insert(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
/*
* Check that the start and end points are not bogus.
*/
if (start < vm_map_min(map) || end > vm_map_max(map) ||
start >= end)
if (!vm_map_range_valid(map, start, end))
return (KERN_INVALID_ADDRESS);
/*
@ -2161,9 +2160,7 @@ vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
goto done;
}
} else if ((cow & MAP_REMAP) != 0) {
if (*addr < vm_map_min(map) ||
*addr + length > vm_map_max(map) ||
*addr + length <= length) {
if (!vm_map_range_valid(map, *addr, *addr + length)) {
rv = KERN_INVALID_ADDRESS;
goto done;
}
@ -4324,9 +4321,8 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
KASSERT(orient != (MAP_STACK_GROWS_DOWN | MAP_STACK_GROWS_UP),
("bi-dir stack"));
if (addrbos < vm_map_min(map) ||
addrbos + max_ssize > vm_map_max(map) ||
addrbos + max_ssize <= addrbos)
if (max_ssize == 0 ||
!vm_map_range_valid(map, addrbos, addrbos + max_ssize))
return (KERN_INVALID_ADDRESS);
sgp = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ||
(curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 :

11
sys/vm/vm_map.h
View File

@ -255,6 +255,17 @@ vm_map_modflags(vm_map_t map, vm_flags_t set, vm_flags_t clear)
{
map->flags = (map->flags | set) & ~clear;
}
static inline bool
vm_map_range_valid(vm_map_t map, vm_offset_t start, vm_offset_t end)
{
if (end < start)
return (false);
if (start < vm_map_min(map) || end > vm_map_max(map))
return (false);
return (true);
}
#endif /* KLD_MODULE */
#endif /* _KERNEL */

25
sys/vm/vm_mmap.c
View File

@ -342,10 +342,7 @@ kern_mmap_req(struct thread *td, const struct mmap_req *mrp)
return (EINVAL);
/* Address range must be all in user VM space. */
if (addr < vm_map_min(&vms->vm_map) ||
addr + size > vm_map_max(&vms->vm_map))
return (EINVAL);
if (addr + size < addr)
if (!vm_map_range_valid(&vms->vm_map, addr, addr + size))
return (EINVAL);
#ifdef MAP_32BIT
if (flags & MAP_32BIT && addr + size > MAP_32BIT_MAX_ADDR)
@ -577,7 +574,7 @@ kern_munmap(struct thread *td, uintptr_t addr0, size_t size)
vm_map_entry_t entry;
bool pmc_handled;
#endif
vm_offset_t addr;
vm_offset_t addr, end;
vm_size_t pageoff;
vm_map_t map;
@ -589,15 +586,11 @@ kern_munmap(struct thread *td, uintptr_t addr0, size_t size)
addr -= pageoff;
size += pageoff;
size = (vm_size_t) round_page(size);
if (addr + size < addr)
end = addr + size;
map = &td->td_proc->p_vmspace->vm_map;
if (!vm_map_range_valid(map, addr, end))
return (EINVAL);
/*
* Check for illegal addresses. Watch out for address wrap...
*/
map = &td->td_proc->p_vmspace->vm_map;
if (addr < vm_map_min(map) || addr + size > vm_map_max(map))
return (EINVAL);
vm_map_lock(map);
#ifdef HWPMC_HOOKS
pmc_handled = false;
@ -609,7 +602,7 @@ kern_munmap(struct thread *td, uintptr_t addr0, size_t size)
*/
pkm.pm_address = (uintptr_t) NULL;
if (vm_map_lookup_entry(map, addr, &entry)) {
for (; entry->start < addr + size;
for (; entry->start < end;
entry = vm_map_entry_succ(entry)) {
if (vm_map_check_protection(map, entry->start,
entry->end, VM_PROT_EXECUTE) == TRUE) {
@ -621,7 +614,7 @@ kern_munmap(struct thread *td, uintptr_t addr0, size_t size)
}
}
#endif
vm_map_delete(map, addr, addr + size);
vm_map_delete(map, addr, end);
#ifdef HWPMC_HOOKS
if (__predict_false(pmc_handled)) {
@ -772,9 +765,7 @@ kern_madvise(struct thread *td, uintptr_t addr0, size_t len, int behav)
*/
map = &td->td_proc->p_vmspace->vm_map;
addr = addr0;
if (addr < vm_map_min(map) || addr + len > vm_map_max(map))
return (EINVAL);
if ((addr + len) < addr)
if (!vm_map_range_valid(map, addr, addr + len))
return (EINVAL);
/*