| From: Dan Carpenter <dan.carpenter@oracle.com> |
| Date: Thu, 4 Apr 2019 18:12:17 +0300 |
| Subject: xen: Prevent buffer overflow in privcmd ioctl |
| |
| commit 42d8644bd77dd2d747e004e367cb0c895a606f39 upstream. |
| |
| The "call" variable comes from the user in privcmd_ioctl_hypercall(). |
| It's an offset into the hypercall_page[] which has (PAGE_SIZE / 32) |
| elements. We need to put an upper bound on it to prevent an out of |
| bounds access. |
| |
| Fixes: 1246ae0bb992 ("xen: add variable hypercall caller") |
| Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> |
| Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> |
| Signed-off-by: Juergen Gross <jgross@suse.com> |
| [bwh: Backported to 3.16: adjust context] |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| arch/x86/include/asm/xen/hypercall.h | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/arch/x86/include/asm/xen/hypercall.h |
| +++ b/arch/x86/include/asm/xen/hypercall.h |
| @@ -215,6 +215,9 @@ privcmd_call(unsigned call, |
| __HYPERCALL_DECLS; |
| __HYPERCALL_5ARG(a1, a2, a3, a4, a5); |
| |
| + if (call >= PAGE_SIZE / sizeof(hypercall_page[0])) |
| + return -EINVAL; |
| + |
| stac(); |
| asm volatile(CALL_NOSPEC |
| : __HYPERCALL_5PARAM |
