Skip to content

Commit

Permalink
---
Browse files Browse the repository at this point in the history
yaml
---
r: 164561
b: refs/heads/master
c: b7f5ab6
h: refs/heads/master
i:
  164559: 9f7bc8d
v: v3
  • Loading branch information
Horst Schirmeier authored and Jiri Kosina committed Sep 21, 2009
1 parent 2200b21 commit 80b286a
Show file tree
Hide file tree
Showing 2 changed files with 18 additions and 14 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 627df23c61ce28043a0715a941605ab42dfeb05e
refs/heads/master: b7f5ab6fbbb9459a91c0acae15097a495f800206
30 changes: 17 additions & 13 deletions trunk/Documentation/sysctl/kernel.txt
Original file line number Diff line number Diff line change
Expand Up @@ -319,25 +319,29 @@ This option can be used to select the type of process address
space randomization that is used in the system, for architectures
that support this feature.

0 - Turn the process address space randomization off by default.
0 - Turn the process address space randomization off. This is the
default for architectures that do not support this feature anyways,
and kernels that are booted with the "norandmaps" parameter.

1 - Make the addresses of mmap base, stack and VDSO page randomized.
This, among other things, implies that shared libraries will be
loaded to random addresses. Also for PIE-linked binaries, the location
of code start is randomized.
loaded to random addresses. Also for PIE-linked binaries, the
location of code start is randomized. This is the default if the
CONFIG_COMPAT_BRK option is enabled.

With heap randomization, the situation is a little bit more
complicated.
There a few legacy applications out there (such as some ancient
2 - Additionally enable heap randomization. This is the default if
CONFIG_COMPAT_BRK is disabled.

There are a few legacy applications out there (such as some ancient
versions of libc.so.5 from 1996) that assume that brk area starts
just after the end of the code+bss. These applications break when
start of the brk area is randomized. There are however no known
just after the end of the code+bss. These applications break when
start of the brk area is randomized. There are however no known
non-legacy applications that would be broken this way, so for most
systems it is safe to choose full randomization. However there is
a CONFIG_COMPAT_BRK option for systems with ancient and/or broken
binaries, that makes heap non-randomized, but keeps all other
parts of process address space randomized if randomize_va_space
sysctl is turned on.
systems it is safe to choose full randomization.

Systems with ancient and/or broken binaries should be configured
with CONFIG_COMPAT_BRK enabled, which excludes the heap from process
address space randomization.

==============================================================

Expand Down

0 comments on commit 80b286a

Please sign in to comment.