From: Dan Williams <dan.j.williams@intel.com>
To: linux-kernel@vger.kernel.org
Cc: linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com,
Al Viro <viro@zeniv.linux.org.uk>,
akpm@linux-foundation.org, torvalds@linux-foundation.org,
tglx@linutronix.de, Elena Reshetova <elena.reshetova@intel.com>,
alan@linux.intel.com
Subject: [PATCH v2 11/19] vfs, fdtable: prevent bounds-check bypass via speculative execution
Date: Thu, 11 Jan 2018 16:47:24 -0800 [thread overview]
Message-ID: <151571804437.27429.14767161104132594707.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <151571798296.27429.7166552848688034184.stgit@dwillia2-desk3.amr.corp.intel.com>
Expectedly, static analysis reports that 'fd' is a user controlled value
that is used as a data dependency to read from the 'fdt->fd' array. In
order to avoid potential leaks of kernel memory values, block
speculative execution of the instruction stream that could issue reads
based on an invalid 'file *' returned from __fcheck_files.
Based on an original patch by Elena Reshetova.
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
include/linux/fdtable.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index 1c65817673db..9731f1a255db 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -10,6 +10,7 @@
#include <linux/compiler.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
+#include <linux/nospec.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/fs.h>
@@ -81,9 +82,11 @@ struct dentry;
static inline struct file *__fcheck_files(struct files_struct *files, unsigned int fd)
{
struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+ struct file __rcu **fdp;
- if (fd < fdt->max_fds)
- return rcu_dereference_raw(fdt->fd[fd]);
+ fdp = array_ptr(fdt->fd, fd, fdt->max_fds);
+ if (fdp)
+ return rcu_dereference_raw(*fdp);
return NULL;
}
next prev parent reply other threads:[~2018-01-12 0:55 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 ` Dan Williams [this message]
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
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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