This is a note to let you know that I've just added the patch titled

vfs, fdtable: Prevent bounds-check bypass via speculative execution

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: vfs_fdtable_Prevent_bounds-check_bypass_via_speculative_execution.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

Subject: vfs, fdtable: Prevent bounds-check bypass via speculative execution From: Dan Williams dan.j.williams@intel.com Date: Mon Jan 29 17:03:05 2018 -0800

From: Dan Williams dan.j.williams@intel.com

commit 56c30ba7b348b90484969054d561f711ba196507

'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.

Co-developed-by: Elena Reshetova elena.reshetova@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: linux-arch@vger.kernel.org Cc: kernel-hardening@lists.openwall.com Cc: gregkh@linuxfoundation.org Cc: Al Viro viro@zeniv.linux.org.uk Cc: torvalds@linux-foundation.org Cc: alan@linux.intel.com Link: https://lkml.kernel.org/r/151727418500.33451.17392199002892248656.stgit@dwil... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- include/linux/fdtable.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

--- 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> @@ -82,8 +83,10 @@ static inline struct file *__fcheck_file { struct fdtable *fdt = rcu_dereference_raw(files->fdt);

- if (fd < fdt->max_fds) + if (fd < fdt->max_fds) { + fd = array_index_nospec(fd, fdt->max_fds); return rcu_dereference_raw(fdt->fd[fd]); + } return NULL; }

Patches currently in stable-queue which might be from elena.reshetova@intel.com are

queue-4.14/nl80211_Sanitize_array_index_in_parse_txq_params.patch queue-4.14/vfs_fdtable_Prevent_bounds-check_bypass_via_speculative_execution.patch