== SRU Justification ==
Artful has a bug in IMA policy parsing introduced by mailine commit 787d8c530af7.
This bug prevents setting IMA measurements and appraisal options per fsuuid.
This commit has been cc'd to upstream stable. However, it has not yet been applied
to Artful, since upstream 4.13 is EOL.
== Fix ==
36447456e1cc ("ima/policy: fix parsing of fsuuid")
== Regression Potential ==
Low. This patch has also been sent to upstream stable, so it has had additional upstream
review.
== Test Case ==
A test kernel was built with this patch and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug.
Linux kernel version 4.13 has a bug in IMA policy parsing that prevents setting IMA measurements and appraisal options per fsuuid.
The issue can be reproduced with simple ima_policy:
# fsuuid=$(blkid -s UUID -o value /dev/sda1)
# cat > ima_policy << EOF
dont_appraise fsuuid=$fsuuid
dont_measure fsuuid=$fsuuid
EOF
# cat ima_policy > /sys/kernel/security/ima/policy
cat: write error: Invalid argument
# dmesg | tail
[ 928.069606] audit: type=1805 audit(1521031959.907:18): action="dont_appraise" fsuuid="aef88a4e-dbea-4cc7-be8b-03cf8501cc8f" res=0
[ 928.069895] audit: type=1802 audit(1521031959.908:19): pid=1806 uid=0 auid=0 ses=1 op="update_policy" cause="invalid-policy" comm="cat" res=0
[ 928.070829] IMA: policy update failed
[ 928.070860] audit: type=1802 audit(1521031959.909:20): pid=1806 uid=0 auid=0 ses=1 op="policy_update" cause="failed" comm="cat" res=0
The same policy can be successfully loaded on v4.10:
(v4.10) # dmesg | tail
[ 54.071383] IMA: policy update completed
[ 54.071484] kauditd_printk_skb: 1 callbacks suppressed
[ 54.071487] audit: type=1805 audit(1521030962.958:15): action="dont_appraise" fsuuid="aef88a4e-dbea-4cc7-be8b-03cf8501cc8f" res=1
[ 54.071491] audit: type=1805 audit(1521030962.958:16): action="dont_measure" fsuuid="aef88a4e-dbea-4cc7-be8b-03cf8501cc8f" res=1
[ 54.071493] audit: type=1802 audit(1521030962.958:17): pid=1793 uid=0 auid=0 ses=1 op="policy_update" cause="completed" comm="cat" res=1
The bug is fixed in the mainline kernel:
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/security/integrity/ima/ima_policy.c?id=36447456e1cca853188505f2a964dbbeacfc7a7a
---
AlsaDevices:
total 0
crw-rw---- 1 root audio 116, 1 Mar 14 12:37 seq
crw-rw---- 1 root audio 116, 33 Mar 14 12:37 timer
AplayDevices: Error: [Errno 2] No such file or directory
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
DistroRelease: Ubuntu 16.04
IwConfig: Error: [Errno 2] No such file or directory
Lsusb: Error: command ['lsusb'] failed with exit code 1:
MachineType: QEMU Standard PC (i440FX + PIIX, 1996)
Package: linux (not installed)
PciMultimedia:
ProcFB:
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.13.0-36-generic root=UUID=aef88a4e-dbea-4cc7-be8b-03cf8501cc8f ro console=tty1 console=ttyS0 crashkernel=384M-2G:128M,2G-:256M
ProcVersionSignature: Ubuntu 4.13.0-36.40~16.04.1-generic 4.13.13
RelatedPackageVersions:
linux-restricted-modules-4.13.0-36-generic N/A
linux-backports-modules-4.13.0-36-generic N/A
linux-firmware 1.157.17
RfKill: Error: [Errno 2] No such file or directory
Tags: xenial uec-images
Uname: Linux 4.13.0-36-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: pkcs11
_MarkForUpload: True
dmi.bios.date: 04/01/2014
dmi.bios.vendor: SeaBIOS
dmi.bios.version: Ubuntu-1.8.2-1ubuntu1
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-i440fx-xenial
dmi.modalias: dmi:bvnSeaBIOS:bvrUbuntu-1.8.2-1ubuntu1:bd04/01/2014:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-xenial:cvnQEMU:ct1:cvrpc-i440fx-xenial:
dmi.product.name: Standard PC (i440FX + PIIX, 1996)
dmi.product.version: pc-i440fx-xenial
dmi.sys.vendor: QEMU
This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1755804
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.