------- Comment From gcwil...@us.ibm.com 2016-03-23 10:29 EDT------- Making comment from Mehmet Kayaalp external:
In the 4.4.0-15.31 kernel the reserved space is not filled with randomized bytes. The second step of the build seems to be skipped. ---quote--- make vmlinux scripts/insert-sys-cert -b vmlinux -c /dev/null make bzImage The 2nd step above changes the reserved memory to randomized. ---quote--- This results in a larger vmlinux when the key is inserted: ubuntu@ubuntu-xenial:~$ uname -a Linux ubuntu-xenial 4.4.0-15-generic #31-Ubuntu SMP Fri Mar 18 19:08:31 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux ubuntu@ubuntu-xenial:~$ sudo grep SYSTEM_EXTRA /boot/config-4.4.0-15-generic CONFIG_SYSTEM_EXTRA_CERTIFICATE=y CONFIG_SYSTEM_EXTRA_CERTIFICATE_SIZE=4096 ubuntu@ubuntu-xenial:~$ sudo ./insert-sys-cert -s /boot/System.map-4.4.0-15-generic -z /boot/vmlinuz-4.4.0-15-generic -c cert.x509 ... INFO: Inserted the contents of cert.x509 into ffffffff82075ffa. INFO: Used 1308 bytes out of 4096 bytes reserved. INFO: Executing: gzip -n -f -9 <vmlinux-PquuG7 >vmlinux-0ZuoLz ERROR: Increase in compressed size is not supported. ERROR: Old size was 6952429, new size is 6956652 -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1558553 Title: IMA-appraisal is unusable in Ubuntu 16.04 Status in linux package in Ubuntu: Fix Released Status in linux source package in Xenial: Fix Released Bug description: At some point, the IMA keyring changed from _ima to a trusted .ima keyring. At that point, we couldn't add keys to the IMA keyring. Other distros import UEFI keys onto the system keyring. Another method of loading keys on the system keyring is needed, which doesn't require the UEFI keys or rebuilding the kernel. To resolve this problem, the kernel should be built so that certificate memory is reserved and randomized. Two patches are being upstreamed in this open window (linux-4.6): 8e16789 KEYS: Use the symbol value for list size, updated by scripts/insert-sys-cert c4c3610 KEYS: Reserve an extra certificate symbol for inserting without recompiling We need to include these Kconfig options to reserve the memory: CONFIG_SYSTEM_EXTRA_CERTIFICATE=y CONFIG_SYSTEM_EXTRA_CERTIFICATE_SIZE=4096 An additional patch, which will be upstreamed, is needed to fill the reserved memory with random data before it is compressed. (The patch is attached.) After compiling the kernel with the reserved memory, the following build step is required: scripts/insert-sys-cert -b vmlinux -c /dev/null If you want to add a cert, the following command will unpack a bzImage, install the cert (DER format) in the vmlinuz, and repack the bzImage. scripts/insert-sys-cert -s <System.map> -z <bzImage> -c <certfile> Contact Information = George Wilson <gcwil...@us.ibm.com> / Mimi Zohar <zo...@us.ibm.com> To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1558553/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
