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author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 10:51:45 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 10:51:45 -0400 |
commit | 342ff1a1b558ebbdb8cbd55ab6a63eca8b2473ca (patch) | |
tree | 1f967f283dade6e03897169bb29513354f49f910 /Documentation/sysctl | |
parent | 50223e486cabdcf7e540e519da1f26bab3084e5d (diff) | |
parent | 24ed7a97464db44592495f98cff8bcee02f92bc2 (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')
-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 | |||
319 | space randomization that is used in the system, for architectures | 319 | space randomization that is used in the system, for architectures |
320 | that support this feature. | 320 | that support this feature. |
321 | 321 | ||
322 | 0 - Turn the process address space randomization off by default. | 322 | 0 - 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 | ||
324 | 1 - Make the addresses of mmap base, stack and VDSO page randomized. | 326 | 1 - 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 | 332 | 2 - 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 | ||