diff options
| author |   Dan Williams <dan.j.williams@intel.com> | 2018-01-29 17:03:05 -0800 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2018-01-30 21:54:32 +0100 |
| commit | 56c30ba7b348b90484969054d561f711ba196507 (patch) | |
| tree | 6e5d8ed79763c5cbf8477f8627ae0545dacc3ff0 /include/linux/fdtable.h | |
| parent | x86/syscall: Sanitize syscall table de-references under speculation (diff) | |
| download | linux-dev-56c30ba7b348b90484969054d561f711ba196507.tar.xz linux-dev-56c30ba7b348b90484969054d561f711ba196507.zip | |
vfs, fdtable: Prevent bounds-check bypass via speculative execution
'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@dwillia2-desk3.amr.corp.intel.com
Diffstat (limited to 'include/linux/fdtable.h')
| -rw-r--r-- | include/linux/fdtable.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h index 1c65817673db..41615f38bcff 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> @@ -82,8 +83,10 @@ static inline struct file *__fcheck_files(struct files_struct *files, unsigned i { 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; } |