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authorLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 10:51:45 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 10:51:45 -0400
commit342ff1a1b558ebbdb8cbd55ab6a63eca8b2473ca (patch)
tree1f967f283dade6e03897169bb29513354f49f910 /Documentation/sysctl/kernel.txt
parent50223e486cabdcf7e540e519da1f26bab3084e5d (diff)
parent24ed7a97464db44592495f98cff8bcee02f92bc2 (diff)
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/kernel.txt')
-rw-r--r--Documentation/sysctl/kernel.txt30
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
319space randomization that is used in the system, for architectures 319space randomization that is used in the system, for architectures
320that support this feature. 320that support this feature.
321 321
3220 - Turn the process address space randomization off by default. 3220 - Turn the process address space randomization off. This is the
323 default for architectures that do not support this feature anyways,
324 and kernels that are booted with the "norandmaps" parameter.
323 325
3241 - Make the addresses of mmap base, stack and VDSO page randomized. 3261 - Make the addresses of mmap base, stack and VDSO page randomized.
325 This, among other things, implies that shared libraries will be 327 This, among other things, implies that shared libraries will be
326 loaded to random addresses. Also for PIE-linked binaries, the location 328 loaded to random addresses. Also for PIE-linked binaries, the
327 of code start is randomized. 329 location of code start is randomized. This is the default if the
330 CONFIG_COMPAT_BRK option is enabled.
328 331
329 With heap randomization, the situation is a little bit more 3322 - Additionally enable heap randomization. This is the default if
330 complicated. 333 CONFIG_COMPAT_BRK is disabled.
331 There a few legacy applications out there (such as some ancient 334
335 There are a few legacy applications out there (such as some ancient
332 versions of libc.so.5 from 1996) that assume that brk area starts 336 versions of libc.so.5 from 1996) that assume that brk area starts
333 just after the end of the code+bss. These applications break when 337 just after the end of the code+bss. These applications break when
334 start of the brk area is randomized. There are however no known 338 start of the brk area is randomized. There are however no known
335 non-legacy applications that would be broken this way, so for most 339 non-legacy applications that would be broken this way, so for most
336 systems it is safe to choose full randomization. However there is 340 systems it is safe to choose full randomization.
337 a CONFIG_COMPAT_BRK option for systems with ancient and/or broken 341
338 binaries, that makes heap non-randomized, but keeps all other 342 Systems with ancient and/or broken binaries should be configured
339 parts of process address space randomized if randomize_va_space 343 with CONFIG_COMPAT_BRK enabled, which excludes the heap from process
340 sysctl is turned on. 344 address space randomization.
341 345
342============================================================== 346==============================================================
343 347