Re: CVE-2014-8159 kernel: infiniband: uverbs: unprotected physical memory access

[Yann Droneaud <ydroneaud () opteya com>]

Hi,

Le mercredi 18 mars 2015 à 17:39 +0000, Shachar Raindel a écrit :
> Hi,
>
> It was found that the Linux kernel's InfiniBand/RDMA subsystem did not
> properly sanitize input parameters while registering memory regions
> from user space via the (u)verbs API. A local user with access to
> a /dev/infiniband/uverbsX device could use this flaw to crash the
> system or, potentially, escalate their privileges on the system.
>
> The issue has been assigned CVE-2014-8159.
>
> The issue exists in the InfiniBand/RDMA/iWARP drivers since Linux
> Kernel version 2.6.13.
>
> Mellanox OFED 2.4-1.0.4 fixes the issue. Available from:
> http://www.mellanox.com/page/products_dyn?product_family=26&mtag=linux_sw_drivers 
>
> RedHat errata: https://access.redhat.com/security/cve/CVE-2014-8159
> Canonical errata: http://people.canonical.com/~ubuntu-security/cve/2014/CVE-2014-8159.html
> Novell (Suse) bug tracking: https://bugzilla.novell.com/show_bug.cgi?id=914742
>
>
> The following patch fixes the issue:
>
> --------------- 8< ------------------------------
>
> From d4d68430d4a12c569e28b4f4468284ea22111186 Mon Sep 17 00:00:00 2001
> From: Shachar Raindel <raindel () mellanox com>
> Date: Sun, 04 Jan 2015 18:30:32 +0200
> Subject: [PATCH] IB/core: Prevent integer overflow in ib_umem_get address arithmetic
>
> Properly verify that the resulting page aligned end address is larger
> than both the start address and the length of the memory area
> requested.
>
> Both the start and length arguments for ib_umem_get are controlled by
> the user. A misbehaving user can provide values which will cause an
> integer overflow when calculating the page aligned end address.
>
> This overflow can cause also miscalculation of the number of pages
> mapped, and additional logic issues.
>
> Signed-off-by: Shachar Raindel <raindel () mellanox com>
> Signed-off-by: Jack Morgenstein <jackm () mellanox com>
> Signed-off-by: Or Gerlitz <ogerlitz () mellanox com>
> ---
>
> diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
> index aec7a6a..8c014b5 100644
> --- a/drivers/infiniband/core/umem.c
> +++ b/drivers/infiniband/core/umem.c
> @@ -99,6 +99,14 @@
>       if (dmasync)
>               dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
>  
> +     /*
> +      * If the combination of the addr and size requested for this memory
> +      * region causes an integer overflow, return error.
> +      */
> +     if ((PAGE_ALIGN(addr + size) <= size) ||
> +         (PAGE_ALIGN(addr + size) <= addr))
> +             return ERR_PTR(-EINVAL);
> +

Can access_ok() be used here ?

         if (!access_ok(writable ? VERIFY_WRITE : VERIFY_READ,
                        addr, size))
                  return ERR_PTR(-EINVAL);


>       if (!can_do_mlock())
>               return ERR_PTR(-EPERM);

Regards.

-- 
Yann Droneaud
OPTEYA