b2dba6634b
Software Kernel TLS needs to allocate a new destination crypto buffer when encrypting data from the page cache, so as to avoid overwriting shared clear-text file data with encrypted data specific to a single socket. When the data is anonymous, eg, not tied to a file, then we can encrypt in place and avoid allocating a new page. This fixes a bug where the existing code always assumes the data is private, and never encrypts in place. This results in unneeded page allocations and potentially more memory bandwidth consumption when doing socket writes. When the code was written at Netflix, ktls_encrypt() looked at private sendfile flags to determine if the pages being encrypted where part of the page cache (coming from sendfile) or anonymous (coming from sosend). This was broken internally at Netflix when the sendfile flags were made private, and the M_WRITABLE() check was added. Unfortunately, M_WRITABLE() will always be false for M_NOMAP mbufs, since one cannot just mtod() them. This change introduces a new flags field to the mbuf_ext_pgs struct by stealing a byte from the tls hdr. Note that the current header is still 2 bytes larger than the largest header we support: AES-CBC with explicit IV. We set MBUF_PEXT_FLAG_ANON when creating an unmapped mbuf in m_uiotombuf_nomap() (which is the path that socket writes take), and we check for that flag in ktls_encrypt() when looking for anon pages. Reviewed by: jhb Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D21796 |
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|---|---|---|
| bin | ||
| cddl | ||
| contrib | ||
| crypto | ||
| etc | ||
| gnu | ||
| include | ||
| kerberos5 | ||
| lib | ||
| libexec | ||
| release | ||
| rescue | ||
| sbin | ||
| secure | ||
| share | ||
| stand | ||
| sys | ||
| targets | ||
| tests | ||
| tools | ||
| usr.bin | ||
| usr.sbin | ||
| .arcconfig | ||
| .arclint | ||
| .cirrus.yml | ||
| .clang-format | ||
| .gitattributes | ||
| .gitignore | ||
| COPYRIGHT | ||
| LOCKS | ||
| MAINTAINERS | ||
| Makefile | ||
| Makefile.inc1 | ||
| Makefile.libcompat | ||
| Makefile.sys.inc | ||
| ObsoleteFiles.inc | ||
| README | ||
| README.md | ||
| RELNOTES | ||
| UPDATING | ||
FreeBSD Source:
This is the top level of the FreeBSD source directory. This file
was last revised on:
FreeBSD
FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms. A large community has continually developed it for more than thirty years. Its advanced networking, security, and storage features have made FreeBSD the platform of choice for many of the busiest web sites and most pervasive embedded networking and storage devices.
For copyright information, please see the file COPYRIGHT in this directory. Additional copyright information also exists for some sources in this tree - please see the specific source directories for more information.
The Makefile in this directory supports a number of targets for building components (or all) of the FreeBSD source tree. See build(7), config(8), https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/makeworld.html, and https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig.html for more information, including setting make(1) variables.
Source Roadmap:
bin System/user commands.
cddl Various commands and libraries under the Common Development
and Distribution License.
contrib Packages contributed by 3rd parties.
crypto Cryptography stuff (see crypto/README).
etc Template files for /etc.
gnu Various commands and libraries under the GNU Public License.
Please see gnu/COPYING* for more information.
include System include files.
kerberos5 Kerberos5 (Heimdal) package.
lib System libraries.
libexec System daemons.
release Release building Makefile & associated tools.
rescue Build system for statically linked /rescue utilities.
sbin System commands.
secure Cryptographic libraries and commands.
share Shared resources.
stand Boot loader sources.
sys Kernel sources.
sys/<arch>/conf Kernel configuration files. GENERIC is the configuration
used in release builds. NOTES contains documentation of
all possible entries.
tests Regression tests which can be run by Kyua. See tests/README
for additional information.
tools Utilities for regression testing and miscellaneous tasks.
usr.bin User commands.
usr.sbin System administration commands.
For information on synchronizing your source tree with one or more of the FreeBSD Project's development branches, please see:
https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/current-stable.html