From 7dd30552d3b750246997e0de9fdd3da0850766e5 Mon Sep 17 00:00:00 2001 From: inference Date: Thu, 27 Jun 2024 15:09:21 +0100 Subject: [PATCH] Update webpage "Documentation - hardened_malloc" from version "5.0.1" to "5.0.2" --- documentation/hardened_malloc.xhtml | 82 ++++++++++++++++------------- 1 file changed, 46 insertions(+), 36 deletions(-) diff --git a/documentation/hardened_malloc.xhtml b/documentation/hardened_malloc.xhtml index ac71b00..72c7af2 100644 --- a/documentation/hardened_malloc.xhtml +++ b/documentation/hardened_malloc.xhtml @@ -1,7 +1,7 @@ - + @@ -34,12 +34,16 @@

This documentation contains instructions to use hardened_malloc - memory allocator as the system's default memory allocator. These instructions apply to both musl and - glibc C libraries on Unix-based and Unix-like systems.

+ memory allocator as the system's default memory allocator via dynamic linking as a shared library. These + instructions apply to both musl and glibc C libraries on Linux-based systems.

hardened_malloc can also be used per-application and/or per-user, in which case root permissions are not required; this documentation focuses on system-wide usage of hardened_malloc, assumes root - privileges, and assumes the compiled library will be located in a path readable and executable by all - users of the system.

+ privileges, and assumes the compiled library will readable and executable by all users of the + system.

+

This documentation uses + Linux Filesystem Hierarchy Standard + paths, with the modern /usr/ merge approach of most Linux distributions. For non-standard + configurations, adjust the paths accordingly.

For the complete hardened_malloc documentation, visit its official documentation.

This documentation is also available in portable AsciiDoc format in my @@ -58,67 +62,73 @@

Increase Permitted Amount of Memory Pages

-

Add vm.max_map_count = 1048576 to /etc/sysctl.conf to accommodate - hardened_malloc's large amount of guard pages.

+

Add the following to /etc/sysctl.conf or a configuration file within + /etc/sysctl.d/to accommodate hardened_malloc's large amount of guard pages:

+ 
vm.max_map_count = 1048576

Clone hardened_malloc Source Code

-

$ git clone https://github.com/GrapheneOS/hardened_malloc.git

+ 
$ git clone https://github.com/GrapheneOS/hardened_malloc.git

Enter hardened_malloc Local Git Repository

-

$ cd hardened_malloc/

+ 
$ cd hardened_malloc/

Compile hardened_malloc

-

$ make <arguments>

+ 
$ make <arguments>

CONFIG_N_ARENA=n can be adjusted to increase parallel performance at the expense of memory usage, or decrease memory usage at the expense of parallel performance, where n is a non-negative integer. Higher values prefer parallel performance, whereas lower values prefer lower memory usage. Note that having too many arenas may cause memory fragmentation and decrease system performance. The number of arenas has no impact on the security properties of hardened_malloc.

- - - - - - - - - - - - - - - -
MinimumMaximumDefault
12564
+
+ + + + + + + + + + + + + + + +
MinimumMaximumDefault
12564
+

For extra security, CONFIG_SEAL_METADATA=true can be used in order to control whether - Memory Protection Keys + Memory Protection Keys are used to disable access to all writable allocator state outside of the memory allocator code. It's currently disabled by default due to a significant performance cost for this use case on current-generation hardware. Whether or not this feature is enabled, the metadata is all contained within an isolated memory region with high-entropy random guard regions around it.

For low-memory systems, VARIANT=light can be used to compile the light variant of - hardened_malloc, which sacrifices some security for much less memory usage. This option still - produces a more hardened memory allocator than both the default musl and glibc allocators, despite - the security sacrifices over the full variant.

+ hardened_malloc, which sacrifices some security for less memory usage. This option still produces a + more hardened memory allocator than both the default musl and glibc allocators, despite the security + sacrifices over the full variant.

For all compile-time options, see the configuration section - of hardened_malloc's extensive official documentation.

+ of hardened_malloc's official documentation.

Copy Compiled hardened_malloc Library

-

# cp out/libhardened_malloc.so <target path>

+ 
# cp out/libhardened_malloc.so /usr/local/lib/libhardened_malloc.so

Set System to Preload hardened_malloc on Boot

-

musl-based systems: Add LD_PRELOAD=<hardened_malloc path> to - /etc/environment

-

glibc-based systems: Add <hardened_malloc path> to - /etc/ld.so.preload

+

In order to preload the hardened_malloc shared library on boot, perform the following + actions:

+

musl-based systems: Add the following to /etc/environment or a configuration + file within /etc/environment.d/:

+ 
LD_PRELOAD=/usr/local/lib/libhardened_malloc.so
+

glibc-based systems: Add the following to /etc/ld.so.preload:

+ 
/usr/local/lib/libhardened_malloc.so
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