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Gustavo A. R. Silva 505b524032 drm/ioctl: Fix Spectre v1 vulnerabilities
nr is indirectly controlled by user-space, hence leading to a
potential exploitation of the Spectre variant 1 vulnerability.

This issue was detected with the help of Smatch:

drivers/gpu/drm/drm_ioctl.c:805 drm_ioctl() warn: potential spectre issue 'dev->driver->ioctls' [r]
drivers/gpu/drm/drm_ioctl.c:810 drm_ioctl() warn: potential spectre issue 'drm_ioctls' [r] (local cap)
drivers/gpu/drm/drm_ioctl.c:892 drm_ioctl_flags() warn: potential spectre issue 'drm_ioctls' [r] (local cap)

Fix this by sanitizing nr before using it to index dev->driver->ioctls
and drm_ioctls.

Notice that given that speculation windows are large, the policy is
to kill the speculation on the first load and not worry if it can be
completed with a dependent load/store [1].

[1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2

Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181220000015.GA18973@embeddedor
2018-12-20 08:13:29 +01:00
arch arch/sh/include/asm/io.h: provide prototypes for PCI I/O mapping in asm/io.h 2018-12-14 15:05:45 -08:00
block
certs
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Documentation XArray updates for 4.20-rc7 2018-12-13 16:35:58 -08:00
drivers drm/ioctl: Fix Spectre v1 vulnerabilities 2018-12-20 08:13:29 +01:00
firmware
fs Merge branch 'akpm' (patches from Andrew) 2018-12-14 15:35:30 -08:00
include mm/sparse: add common helper to mark all memblocks present 2018-12-14 15:05:45 -08:00
init psi: fix reference to kernel commandline enable 2018-12-14 15:05:45 -08:00
ipc
kernel
lib XArray: Fix xa_alloc when id exceeds max 2018-12-13 14:07:33 -05:00
LICENSES
mm hugetlbfs: call VM_BUG_ON_PAGE earlier in free_huge_page() 2018-12-14 15:05:45 -08:00
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samples
scripts scripts/spdxcheck.py: always open files in binary mode 2018-12-14 15:05:45 -08:00
security
sound
tools XArray updates for 4.20-rc7 2018-12-13 16:35:58 -08:00
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MAINTAINERS drm vmwgfx, mediatek, nouveau, amdgpu, rockchip, intel fixes 2018-12-14 09:12:02 -08:00
Makefile Linux 4.20-rc7 2018-12-16 15:46:55 -08:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.