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usercopy: Handle vm_map_ram() areas 

vmalloc does not allocate a vm_struct for vm_map_ram() areas.  That causes
us to deny usercopies from those areas.  This affects XFS which uses
vm_map_ram() for its directories.

Fix this by calling find_vmap_area() instead of find_vm_area().

Fixes: 0aef499f31 ("mm/usercopy: Detect vmalloc overruns")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Tested-by: Zorro Lang <zlang@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220612213227.3881769-2-willy@infradead.org
This commit is contained in:
Matthew Wilcox (Oracle) 2022-06-12 22:32:25 +01:00 committed by Kees Cook
parent 57cd6d157e
commit 993d0b287e
3 changed files with 6 additions and 7 deletions
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1
include/linux/vmalloc.h
View File

@ -215,6 +215,7 @@ extern struct vm_struct *__get_vm_area_caller(unsigned long size,
void free_vm_area(struct vm_struct *area);
extern struct vm_struct *remove_vm_area(const void *addr);
extern struct vm_struct *find_vm_area(const void *addr);
struct vmap_area *find_vmap_area(unsigned long addr);
static inline bool is_vm_area_hugepages(const void *addr)
{

10
mm/usercopy.c
View File

@ -173,16 +173,14 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
}
if (is_vmalloc_addr(ptr)) {
struct vm_struct *area = find_vm_area(ptr);
struct vmap_area *area = find_vmap_area((unsigned long)ptr);
unsigned long offset;
if (!area) {
if (!area)
usercopy_abort("vmalloc", "no area", to_user, 0, n);
return;
}
offset = ptr - area->addr;
if (offset + n > get_vm_area_size(area))
offset = (unsigned long)ptr - area->va_start;
if ((unsigned long)ptr + n > area->va_end)
usercopy_abort("vmalloc", NULL, to_user, offset, n);
return;
}

2
mm/vmalloc.c
View File

@ -1798,7 +1798,7 @@ static void free_unmap_vmap_area(struct vmap_area *va)
free_vmap_area_noflush(va);
}
static struct vmap_area *find_vmap_area(unsigned long addr)
struct vmap_area *find_vmap_area(unsigned long addr)
{
struct vmap_area *va;