Commit 993d0b28 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Kees Cook
Browse files

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: 0aef499f ("mm/usercopy: Detect vmalloc overruns")
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarUladzislau Rezki (Sony) <urezki@gmail.com>
Tested-by: default avatarZorro Lang <zlang@redhat.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220612213227.3881769-2-willy@infradead.org
parent 57cd6d15

include/linux/vmalloc.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

{

mm/usercopy.c

+4 −6
Original line number Diff line number Diff line
@@ -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;

	}

mm/vmalloc.c

+1 −1
Original line number Diff line number Diff line
@@ -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;