The patch protects from leaking sensitive data after resume from suspend.
During suspend a temporary key is created and this key is used to encrypt the
data written to disk. When, during resume, the data was read back into memory
the temporary key is destroyed which simply means that all data written to
disk during suspend are then inaccessible so they can't be stolen lateron.
Think of the following: you suspend while an application is running that keeps
sensitive data in memory. The application itself prevents the data from being
swapped out. Suspend, however, must write these data to swap to be able to
resume lateron. Without suspend encryption your sensitive data are then
stored in plaintext on disk. This means that after resume your sensitive data
are accessible to all applications having direct access to the swap device
which was used for suspend. If you don't need swap after resume these data
can remain on disk virtually forever. Thus it can happen that your system
gets broken in weeks later and sensitive data which you thought were encrypted
and protected are retrieved and stolen from the swap device.
Signed-off-by: Andreas Steinmetz <ast@domdv.de>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Show swsuspend only on .config where it can compile. I got this on PPC32 &&
SMP:
kernel/power/smp.c:24: error: storage size of `ctxt' isn't known
Also mark swsusp as no longer experimental.
Signed-off-by: Olaf Hering <olh@suse.de>
Signed-off-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Using CPU hotplug to support suspend/resume SMP. Both S3 and S4 use
disable/enable_nonboot_cpus API. The S4 part is based on Pavel's original S4
SMP patch.
Signed-off-by: Li Shaohua<shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Andreas Steinmetz