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Yonghong Song 239946314e bpf: possibly avoid extra masking for narrower load in verifier
Commit 31fd85816d ("bpf: permits narrower load from bpf program
context fields") permits narrower load for certain ctx fields.
The commit however will already generate a masking even if
the prog-specific ctx conversion produces the result with
narrower size.

For example, for __sk_buff->protocol, the ctx conversion
loads the data into register with 2-byte load.
A narrower 2-byte load should not generate masking.
For __sk_buff->vlan_present, the conversion function
set the result as either 0 or 1, essentially a byte.
The narrower 2-byte or 1-byte load should not generate masking.

To avoid unnecessary masking, prog-specific *_is_valid_access
now passes converted_op_size back to verifier, which indicates
the valid data width after perceived future conversion.
Based on this information, verifier is able to avoid
unnecessary marking.

Since we want more information back from prog-specific
*_is_valid_access checking, all of them are packed into
one data structure for more clarity.

Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-23 14:04:11 -04:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-21 17:35:22 -04:00
block block: Fix a blk_exit_rl() regression 2017-06-14 13:27:50 -06:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto : asymmetric_keys : verify_pefile:zero memory content before freeing 2017-06-09 13:29:50 +10:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-21 17:35:22 -04:00
drivers net: stmmac: make some functions static 2017-06-23 13:58:39 -04:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-21 17:35:22 -04:00
include bpf: possibly avoid extra masking for narrower load in verifier 2017-06-23 14:04:11 -04:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel bpf: possibly avoid extra masking for narrower load in verifier 2017-06-23 14:04:11 -04:00
lib net: manual clean code which call skb_put_[data:zero] 2017-06-20 13:30:15 -04:00
mm Allow stack to grow up to address space limit 2017-06-21 11:07:18 -07:00
net bpf: possibly avoid extra masking for narrower load in verifier 2017-06-23 14:04:11 -04:00
samples samples/bpf: fix a build problem 2017-06-22 11:35:19 -04:00
scripts scripts/gdb: make lx-dmesg command work (reliably) 2017-06-02 15:07:38 -07:00
security Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-21 17:35:22 -04:00
sound ALSA: timer: Fix missing queue indices reset at SNDRV_TIMER_IOCTL_SELECT 2017-06-07 10:25:23 +02:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-21 17:35:22 -04:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Handle possible NULL stage2 pud when ageing pages 2017-06-06 15:28:40 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig kbuild: migrate all arch to the kconfig mainmenu upgrade 2010-09-19 22:54:11 -04:00
MAINTAINERS tls: kernel TLS support 2017-06-15 12:12:40 -04:00
Makefile Linux 4.12-rc6 2017-06-19 22:19:37 +08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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.