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Linus Torvalds 594cc251fd make 'user_access_begin()' do 'access_ok()'
Originally, the rule used to be that you'd have to do access_ok()
separately, and then user_access_begin() before actually doing the
direct (optimized) user access.

But experience has shown that people then decide not to do access_ok()
at all, and instead rely on it being implied by other operations or
similar.  Which makes it very hard to verify that the access has
actually been range-checked.

If you use the unsafe direct user accesses, hardware features (either
SMAP - Supervisor Mode Access Protection - on x86, or PAN - Privileged
Access Never - on ARM) do force you to use user_access_begin().  But
nothing really forces the range check.

By putting the range check into user_access_begin(), we actually force
people to do the right thing (tm), and the range check vill be visible
near the actual accesses.  We have way too long a history of people
trying to avoid them.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 12:56:09 -08:00
arch make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
block for-4.21/block-20190102 2019-01-02 18:49:58 -08:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto Kconfig updates for v4.21 2018-12-29 13:03:29 -08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-01-03 12:53:47 -08:00
drivers make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
firmware firmware: refactor firmware/Makefile 2018-12-23 10:10:32 +09:00
fs Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
include make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
init Merge tag 'devicetree-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux 2018-12-28 20:08:34 -08:00
ipc ipc: IPCMNI limit check for semmni 2018-10-31 08:54:14 -07:00
kernel make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
lib make 'user_access_begin()' do 'access_ok()' 2019-01-04 12:56:09 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
net Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
samples Merge branch 'next-seccomp' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-01-02 09:48:13 -08:00
scripts Tracing changes for v4.21: 2018-12-31 11:46:59 -08:00
security Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
sound Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
tools Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
usr user/Makefile: Fix typo and capitalization in comment section 2018-12-11 00:18:03 +09:00
virt Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
.clang-format page cache: Convert find_get_pages_contig to XArray 2018-10-21 10:46:34 -04:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support for DT binding schema checks 2018-12-13 09:41:32 -06:00
.mailmap Merge tag 'nand/for-4.21' of git://git.infradead.org/linux-mtd into mtd/next 2018-12-18 19:59:16 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS: update entry for MMP platform 2018-12-03 12:39:57 -08:00
Kbuild kbuild: remove unused cmd_gentimeconst 2018-12-25 00:10:30 +09:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS Merge branch 'for-linus-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml 2019-01-02 18:39:22 -08:00
Makefile Kbuild updates for v4.21 2018-12-29 12:03:17 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.