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doc: RELRO revert

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nia 2021-11-07 11:30:19 +00:00
parent bf115b5cf8
commit 642d8b5360
2 changed files with 48 additions and 53 deletions
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8
doc/NEWS
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@ -1,4 +1,4 @@
# $NetBSD: NEWS,v 1.21 2021/10/10 08:39:40 nia Exp $
# $NetBSD: NEWS,v 1.22 2021/11/07 11:30:19 nia Exp $
PKGSRC NEWS
===========
@ -24,12 +24,6 @@ Increased enabled-by-default hardening options [nia 2021-09-27]
like i386 - usually this is due to unsafe assembly code,
which should be disabled when MKPIE is enabled.
PKGSRC_USE_RELRO was enabled on some architectures.
This should not affect the majority of packages that properly
honor CFLAGS/LDFLAGS when building. Packages experiencing
problems loading dynamic ELF plugins at runtime should have
RELRO disabled.
PKGSRC_USE_SSP was bumped from "yes" to "strong". This
is not expected to have a noticable effect.

93
doc/guide/files/hardening.xml
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@ -1,4 +1,4 @@
<!-- $NetBSD: hardening.xml,v 1.4 2021/11/02 08:28:45 nia Exp $ -->
<!-- $NetBSD: hardening.xml,v 1.5 2021/11/07 11:30:19 nia Exp $ -->
<appendix id="hardening">
<title>Security hardening</title>
@ -143,51 +143,6 @@ Currently, this means NetBSD on x86, ARM, SPARC64, m68k, and MIPS.
</para>
</sect3>
<sect3 id="hardening.mechanisms.enabled.relro">
<title>PKGSRC_USE_RELRO</title>
<para>
This also makes the exploitation of some security vulnerabilities more
difficult in some cases.
</para>
<para>Two different mitigation levels are available:</para>
<itemizedlist>
<listitem>
<para>
partial: the ELF sections are reordered so that internal data sections
precede the program's own data sections, and non-PLT GOT is read-only;
</para>
</listitem>
<listitem>
<para>
full: in addition to partial RELRO, every relocation is performed immediately
when starting the program (with a slight performance impact), allowing the
entire GOT to be read-only.
</para>
</listitem>
</itemizedlist>
<para>
This is currently supported by GCC. Many software distributions now enable this
feature by default, at the "partial" level.
</para>
<para>
More details can be found here:
</para>
<itemizedlist>
<listitem>
<para>
<ulink url="https://www.redhat.com/en/blog/hardening-elf-binaries-using-relocation-read-only-relro">Hardening ELF binaries using Relocation Read-Only (RELRO)</ulink>
</para>
</listitem>
</itemizedlist>
</sect3>
</sect2>
<sect2 id="hardening.mechanisms.disabled">
<title>Not enabled by default</title>
@ -219,6 +174,52 @@ More work likely needs to be done before pkgsrc is fully reproducible.
</para>
</sect3>
<sect3 id="hardening.mechanisms.enabled.relro">
<title>PKGSRC_USE_RELRO</title>
<para>
This also makes the exploitation of some security vulnerabilities more
difficult in some cases.
</para>
<para>Two different mitigation levels are available:</para>
<itemizedlist>
<listitem>
<para>
partial: the ELF sections are reordered so that internal data sections
precede the program's own data sections, and non-PLT GOT is read-only;
</para>
</listitem>
<listitem>
<para>
full: in addition to partial RELRO, every relocation is performed immediately
when starting the program (with a slight performance impact), allowing the
entire GOT to be read-only.
</para>
</listitem>
</itemizedlist>
<para>
This is currently supported by GCC. Many software distributions now enable this
feature by default, at the "partial" level. However, it cannot yet be enforced
globally in pkgsrc through cwrappers.
</para>
<para>
More details can be found here:
</para>
<itemizedlist>
<listitem>
<para>
<ulink url="https://www.redhat.com/en/blog/hardening-elf-binaries-using-relocation-read-only-relro">Hardening ELF binaries using Relocation Read-Only (RELRO)</ulink>
</para>
</listitem>
</itemizedlist>
</sect3>
</sect2>
<sect3 id="hardening.mechanisms.disabled.stackcheck">
<title>PKGSRC_USE_STACK_CHECK</title>