Author: Jiri Kosina <[EMAIL PROTECTED]>
AuthorDate: Sat Feb 9 23:24:08 2008 +0100
Committer: Thomas Gleixner <[EMAIL PROTECTED]>
CommitDate: Sat Feb 9 23:24:08 2008 +0100
brk: document randomize_va_space and CONFIG_COMPAT_BRK (was Re:
Document randomize_va_space and CONFIG_COMPAT_BRK.
Signed-off-by: Jiri Kosina <[EMAIL PROTECTED]>
Signed-off-by: Ingo Molnar <[EMAIL PROTECTED]>
Signed-off-by: Thomas Gleixner <[EMAIL PROTECTED]>
Documentation/sysctl/kernel.txt | 29 +++++++++++++++++++++++++++++
1 files changed, 29 insertions(+), 0 deletions(-)
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 8984a53..dc8801d 100644
@@ -41,6 +41,7 @@ show up in /proc/sys/kernel:
- powersave-nap [ PPC only ]
- real-root-dev ==> Documentation/initrd.txt
- reboot-cmd [ SPARC only ]
@@ -280,6 +281,34 @@ send before ratelimiting kicks in.
+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.
+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.
+ With heap randomization, the situation is a little bit more
+ There 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
+ 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.
reboot-cmd: (Sparc only)
??? This seems to be a way to give an argument to the Sparc
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