From: Jan Kara <jack@suse.cz>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
kernel-hardening@lists.openwall.com, Jan Kara <jack@suse.com>,
tglx@linutronix.de, torvalds@linux-foundation.org,
akpm@linux-foundation.org,
Elena Reshetova <elena.reshetova@intel.com>,
alan@linux.intel.com
Subject: Re: [PATCH v2 13/19] udf: prevent bounds-check bypass via speculative execution
Date: Mon, 15 Jan 2018 11:32:20 +0100 [thread overview]
Message-ID: <20180115103220.g3xtdsybkfxqkapx@quack2.suse.cz> (raw)
In-Reply-To: <151571805555.27429.728109914195885407.stgit@dwillia2-desk3.amr.corp.intel.com>
On Thu 11-01-18 16:47:35, Dan Williams wrote:
> Static analysis reports that 'eahd->appAttrLocation' and
> 'eahd->impAttrLocation' may be a user controlled values that are used as
> data dependencies for calculating source and destination buffers for
> memmove operations. In order to avoid potential leaks of kernel memory
> values, block speculative execution of the instruction stream that could
> issue further reads based on invalid 'aal' or 'ial' values.
>
> Based on an original patch by Elena Reshetova.
>
> Cc: Jan Kara <jack@suse.com>
> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dan, I've already emailed to you [1] why I don't think this patch is needed
at all. Do you disagree or did my email just get lost?
[1] https://marc.info/?l=linux-arch&m=151540683024125&w=2
Honza
> ---
> fs/udf/misc.c | 40 ++++++++++++++++++++++------------------
> 1 file changed, 22 insertions(+), 18 deletions(-)
>
> diff --git a/fs/udf/misc.c b/fs/udf/misc.c
> index 401e64cde1be..693e24699928 100644
> --- a/fs/udf/misc.c
> +++ b/fs/udf/misc.c
> @@ -22,6 +22,7 @@
> #include "udfdecl.h"
>
> #include <linux/fs.h>
> +#include <linux/nospec.h>
> #include <linux/string.h>
> #include <linux/crc-itu-t.h>
>
> @@ -51,6 +52,8 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
> int offset;
> uint16_t crclen;
> struct udf_inode_info *iinfo = UDF_I(inode);
> + uint8_t *ea_dst, *ea_src;
> + uint32_t aal, ial;
>
> ea = iinfo->i_ext.i_data;
> if (iinfo->i_lenEAttr) {
> @@ -100,33 +103,34 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
>
> offset = iinfo->i_lenEAttr;
> if (type < 2048) {
> - if (le32_to_cpu(eahd->appAttrLocation) <
> - iinfo->i_lenEAttr) {
> - uint32_t aal =
> - le32_to_cpu(eahd->appAttrLocation);
> - memmove(&ea[offset - aal + size],
> - &ea[aal], offset - aal);
> + aal = le32_to_cpu(eahd->appAttrLocation);
> + ea_dst = array_ptr(ea, offset - aal + size,
> + iinfo->i_lenEAttr);
> + ea_src = array_ptr(ea, aal, iinfo->i_lenEAttr);
> + if (ea_dst && ea_src) {
> + memmove(ea_dst, ea_src, offset - aal);
> offset -= aal;
> eahd->appAttrLocation =
> cpu_to_le32(aal + size);
> }
> - if (le32_to_cpu(eahd->impAttrLocation) <
> - iinfo->i_lenEAttr) {
> - uint32_t ial =
> - le32_to_cpu(eahd->impAttrLocation);
> - memmove(&ea[offset - ial + size],
> - &ea[ial], offset - ial);
> +
> + ial = le32_to_cpu(eahd->impAttrLocation);
> + ea_dst = array_ptr(ea, offset - ial + size,
> + iinfo->i_lenEAttr);
> + ea_src = array_ptr(ea, ial, iinfo->i_lenEAttr);
> + if (ea_dst && ea_src) {
> + memmove(ea_dst, ea_src, offset - ial);
> offset -= ial;
> eahd->impAttrLocation =
> cpu_to_le32(ial + size);
> }
> } else if (type < 65536) {
> - if (le32_to_cpu(eahd->appAttrLocation) <
> - iinfo->i_lenEAttr) {
> - uint32_t aal =
> - le32_to_cpu(eahd->appAttrLocation);
> - memmove(&ea[offset - aal + size],
> - &ea[aal], offset - aal);
> + aal = le32_to_cpu(eahd->appAttrLocation);
> + ea_dst = array_ptr(ea, offset - aal + size,
> + iinfo->i_lenEAttr);
> + ea_src = array_ptr(ea, aal, iinfo->i_lenEAttr);
> + if (ea_dst && ea_src) {
> + memmove(ea_dst, ea_src, offset - aal);
> offset -= aal;
> eahd->appAttrLocation =
> cpu_to_le32(aal + size);
>
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2018-01-15 10:32 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 0:46 [PATCH v2 00/19] prevent bounds-check bypass via speculative execution Dan Williams
2018-01-12 0:46 ` [PATCH v2 01/19] Documentation: document array_ptr Dan Williams
2018-01-12 10:38 ` Geert Uytterhoeven
2018-01-16 21:01 ` Kees Cook
2018-01-12 0:46 ` [PATCH v2 02/19] arm64: implement ifence_array_ptr() Dan Williams
2018-01-12 0:46 ` [PATCH v2 03/19] arm: " Dan Williams
2018-01-12 0:46 ` [PATCH v2 04/19] x86: implement ifence() Dan Williams
2018-01-12 2:27 ` Eric W. Biederman
2018-01-12 3:39 ` Dan Williams
2018-01-12 0:46 ` [PATCH v2 05/19] x86: implement ifence_array_ptr() and array_ptr_mask() Dan Williams
2018-01-12 0:46 ` [PATCH v2 06/19] asm-generic/barrier: mask speculative execution flows Dan Williams
2018-01-12 2:42 ` Eric W. Biederman
2018-01-12 9:12 ` Peter Zijlstra
2018-01-13 0:41 ` Dan Williams
2018-01-15 8:46 ` Peter Zijlstra
2018-01-12 0:47 ` [PATCH v2 07/19] x86: introduce __uaccess_begin_nospec and ASM_IFENCE Dan Williams
2018-01-12 17:51 ` Josh Poimboeuf
2018-01-12 18:21 ` Dan Williams
2018-01-12 18:58 ` Josh Poimboeuf
2018-01-12 19:26 ` Dan Williams
2018-01-12 20:01 ` Linus Torvalds
2018-01-12 20:41 ` Josh Poimboeuf
2018-01-12 0:47 ` [PATCH v2 08/19] x86: use __uaccess_begin_nospec and ASM_IFENCE in get_user paths Dan Williams
2018-01-12 1:11 ` Linus Torvalds
2018-01-12 1:14 ` Dan Williams
2018-01-12 0:47 ` [PATCH v2 09/19] ipv6: prevent bounds-check bypass via speculative execution Dan Williams
2018-01-12 0:47 ` [PATCH v2 10/19] ipv4: " Dan Williams
2018-01-12 7:59 ` Greg KH
2018-01-12 18:47 ` Dan Williams
2018-01-13 8:56 ` Greg KH
2018-01-12 0:47 ` [PATCH v2 11/19] vfs, fdtable: " Dan Williams
2018-01-12 0:47 ` [PATCH v2 12/19] userns: " Dan Williams
2018-01-12 0:47 ` [PATCH v2 13/19] udf: " Dan Williams
2018-01-15 10:32 ` Jan Kara [this message]
2018-01-15 17:49 ` Dan Williams
2018-01-12 0:47 ` [PATCH v2 14/19] [media] uvcvideo: " Dan Williams
2018-08-06 21:40 ` Laurent Pinchart
2018-01-12 0:47 ` [PATCH v2 15/19] carl9170: " Dan Williams
2018-01-12 14:42 ` Christian Lamparter
2018-01-12 18:39 ` Dan Williams
2018-01-12 20:01 ` Christian Lamparter
2018-01-12 23:05 ` Dan Williams
2018-01-12 0:47 ` [PATCH v2 16/19] p54: " Dan Williams
2018-01-12 0:47 ` [PATCH v2 17/19] qla2xxx: " Dan Williams
2018-01-12 1:19 ` James Bottomley
2018-01-12 5:38 ` Dan Williams
2018-01-12 6:05 ` James Bottomley
2018-01-12 0:48 ` [PATCH v2 18/19] cw1200: " Dan Williams
2018-01-12 0:48 ` [PATCH v2 19/19] net: mpls: " Dan Williams
2018-01-12 1:19 ` [PATCH v2 00/19] " Linus Torvalds
2018-01-12 1:41 ` Dan Williams
2018-01-18 13:18 ` Will Deacon
2018-01-18 16:58 ` Dan Williams
2018-01-18 17:05 ` Will Deacon
2018-01-18 21:41 ` Laurent Pinchart
2018-01-13 0:15 ` Tony Luck
2018-01-13 18:51 ` Linus Torvalds
2018-01-16 19:21 ` Tony Luck
2018-01-12 10:02 ` Russell King - ARM Linux
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