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authorDan Carpenter <dan.carpenter@oracle.com>2019-04-04 18:12:17 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-04-17 08:36:47 +0200
commit356bcb7b4eaa2fb92332344b5d1c1e47103b6999 (patch)
tree1f858c11ae833daf7d8b3ed39269aea3db1c1a2f
parent79bedcb095bdc5c83db65180b414a8b0ac89b91d (diff)
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. Cc: stable@vger.kernel.org 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/include/asm/xen/hypercall.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h
index ccdc23d89b60..9f694537a103 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -216,6 +216,9 @@ 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