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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:51:45 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:51:45 -0700 |
commit | 342ff1a1b558ebbdb8cbd55ab6a63eca8b2473ca (patch) | |
tree | 1f967f283dade6e03897169bb29513354f49f910 /Documentation/sysctl | |
parent | 50223e486cabdcf7e540e519da1f26bab3084e5d (diff) | |
parent | 24ed7a97464db44592495f98cff8bcee02f92bc2 (diff) | |
download | lwn-342ff1a1b558ebbdb8cbd55ab6a63eca8b2473ca.tar.gz lwn-342ff1a1b558ebbdb8cbd55ab6a63eca8b2473ca.zip |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits)
trivial: fix typo in aic7xxx comment
trivial: fix comment typo in drivers/ata/pata_hpt37x.c
trivial: typo in kernel-parameters.txt
trivial: fix typo in tracing documentation
trivial: add __init/__exit macros in drivers/gpio/bt8xxgpio.c
trivial: add __init macro/ fix of __exit macro location in ipmi_poweroff.c
trivial: remove unnecessary semicolons
trivial: Fix duplicated word "options" in comment
trivial: kbuild: remove extraneous blank line after declaration of usage()
trivial: improve help text for mm debug config options
trivial: doc: hpfall: accept disk device to unload as argument
trivial: doc: hpfall: reduce risk that hpfall can do harm
trivial: SubmittingPatches: Fix reference to renumbered step
trivial: fix typos "man[ae]g?ment" -> "management"
trivial: media/video/cx88: add __init/__exit macros to cx88 drivers
trivial: fix typo in CONFIG_DEBUG_FS in gcov doc
trivial: fix missing printk space in amd_k7_smp_check
trivial: fix typo s/ketymap/keymap/ in comment
trivial: fix typo "to to" in multiple files
trivial: fix typos in comments s/DGBU/DBGU/
...
Diffstat (limited to 'Documentation/sysctl')
-rw-r--r-- | Documentation/sysctl/kernel.txt | 30 |
1 files changed, 17 insertions, 13 deletions
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt index 2dbff53369d0..3e5b63ebb821 100644 --- a/Documentation/sysctl/kernel.txt +++ b/Documentation/sysctl/kernel.txt @@ -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. ============================================================== |