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Filename Latest commit message Latest commit date
Luck, Tony bef3efbeb8 efivarfs: Limit the rate for non-root to read files
Each read from a file in efivarfs results in two calls to EFI
(one to get the file size, another to get the actual data).

On X86 these EFI calls result in broadcast system management
interrupts (SMI) which affect performance of the whole system.
A malicious user can loop performing reads from efivarfs bringing
the system to its knees.

Linus suggested per-user rate limit to solve this.

So we add a ratelimit structure to "user_struct" and initialize
it for the root user for no limit. When allocating user_struct for
other users we set the limit to 100 per second. This could be used
for other places that want to limit the rate of some detrimental
user action.

In efivarfs if the limit is exceeded when reading, we take an
interruptible nap for 50ms and check the rate limit again.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-02-22 10:21:02 -08:00
arch x86: Treat R_X86_64_PLT32 as R_X86_64_PC32 2018-02-22 09:01:10 -08:00
block blk: optimization for classic polling 2018-02-13 09:12:04 -07:00
certs
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2018-02-12 08:57:21 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-19 11:58:19 -08:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-19 11:58:19 -08:00
firmware
fs efivarfs: Limit the rate for non-root to read files 2018-02-22 10:21:02 -08:00
include efivarfs: Limit the rate for non-root to read files 2018-02-22 10:21:02 -08:00
init membarrier: Provide core serializing command, *_SYNC_CORE 2018-02-05 21:35:03 +01:00
ipc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kernel efivarfs: Limit the rate for non-root to read files 2018-02-22 10:21:02 -08:00
lib dma-direct: comment the dma_direct_free calling convention 2018-02-12 15:59:07 +00:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm mm: hide a #warning for COMPILE_TEST 2018-02-16 09:41:36 -08:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-02-19 11:58:19 -08:00
samples sample/bpf: fix erspan metadata 2018-02-06 11:32:49 -05:00
scripts Kbuild updates for v4.16 (2nd) 2018-02-09 19:32:41 -08:00
security vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
sound ALSA: hda/realtek: PCI quirk for Fujitsu U7x7 2018-02-14 12:02:26 +01:00
tools perf/core improvements and fixes: 2018-02-16 09:10:09 +01:00
usr
virt vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap mailmap: update Mark Yao's email address 2018-01-04 16:45:09 -08:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Remove Richard Purdie from LED maintainers 2018-02-19 20:23:49 +01:00
Makefile Linux 4.16-rc2 2018-02-18 17:29:42 -08:00
README

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.