forked from luck/tmp_suning_uos_patched
e6e5494cb2
Move the i386 VDSO down into a vma and thus randomize it. Besides the security implications, this feature also helps debuggers, which can COW a vma-backed VDSO just like a normal DSO and can thus do single-stepping and other debugging features. It's good for hypervisors (Xen, VMWare) too, which typically live in the same high-mapped address space as the VDSO, hence whenever the VDSO is used, they get lots of guest pagefaults and have to fix such guest accesses up - which slows things down instead of speeding things up (the primary purpose of the VDSO). There's a new CONFIG_COMPAT_VDSO (default=y) option, which provides support for older glibcs that still rely on a prelinked high-mapped VDSO. Newer distributions (using glibc 2.3.3 or later) can turn this option off. Turning it off is also recommended for security reasons: attackers cannot use the predictable high-mapped VDSO page as syscall trampoline anymore. There is a new vdso=[0|1] boot option as well, and a runtime /proc/sys/vm/vdso_enabled sysctl switch, that allows the VDSO to be turned on/off. (This version of the VDSO-randomization patch also has working ELF coredumping, the previous patch crashed in the coredumping code.) This code is a combined work of the exec-shield VDSO randomization code and Gerd Hoffmann's hypervisor-centric VDSO patch. Rusty Russell started this patch and i completed it. [akpm@osdl.org: cleanups] [akpm@osdl.org: compile fix] [akpm@osdl.org: compile fix 2] [akpm@osdl.org: compile fix 3] [akpm@osdl.org: revernt MAXMEM change] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Cc: Gerd Hoffmann <kraxel@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Zachary Amsden <zach@vmware.com> Cc: Andi Kleen <ak@muc.de> Cc: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
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| .. | ||
| irq | ||
| power | ||
| time | ||
| .gitignore | ||
| acct.c | ||
| audit.c | ||
| audit.h | ||
| auditfilter.c | ||
| auditsc.c | ||
| capability.c | ||
| compat.c | ||
| configs.c | ||
| cpu.c | ||
| cpuset.c | ||
| dma.c | ||
| exec_domain.c | ||
| exit.c | ||
| extable.c | ||
| fork.c | ||
| futex_compat.c | ||
| futex.c | ||
| hrtimer.c | ||
| itimer.c | ||
| kallsyms.c | ||
| Kconfig.hz | ||
| Kconfig.preempt | ||
| kexec.c | ||
| kfifo.c | ||
| kmod.c | ||
| kprobes.c | ||
| ksysfs.c | ||
| kthread.c | ||
| Makefile | ||
| module.c | ||
| mutex-debug.c | ||
| mutex-debug.h | ||
| mutex.c | ||
| mutex.h | ||
| panic.c | ||
| params.c | ||
| pid.c | ||
| posix-cpu-timers.c | ||
| posix-timers.c | ||
| printk.c | ||
| profile.c | ||
| ptrace.c | ||
| rcupdate.c | ||
| rcutorture.c | ||
| relay.c | ||
| resource.c | ||
| sched.c | ||
| seccomp.c | ||
| signal.c | ||
| softirq.c | ||
| softlockup.c | ||
| spinlock.c | ||
| stop_machine.c | ||
| sys_ni.c | ||
| sys.c | ||
| sysctl.c | ||
| time.c | ||
| timer.c | ||
| uid16.c | ||
| unwind.c | ||
| user.c | ||
| wait.c | ||
| workqueue.c | ||