[Bug 2071478] Update Released
Ćukasz Zemczak
2071478 at bugs.launchpad.net
Wed Aug 21 15:47:57 UTC 2024
The verification of the Stable Release Update for swtpm has completed
successfully and the package is now being released to -updates.
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https://bugs.launchpad.net/bugs/2071478
Title:
Add sys_admin capability to apparmor profile by default
Status in swtpm package in Ubuntu:
Fix Released
Status in swtpm source package in Jammy:
Fix Committed
Status in swtpm source package in Mantic:
Won't Fix
Status in swtpm source package in Noble:
Fix Released
Status in swtpm source package in Oracular:
Fix Released
Bug description:
[Impact]
The default apparmor profile for swtpm blocks access to kernel
modules, which causes a failure when using the --vtpm-proxy argument,
since it requires tpm_vtpm_proxy.
The fix for this should be backported so the vtpm-proxy works for
users by default.
The issue is fixed by adding the sys_admin capability, which gives
swtpm access to the required kernel modules
[Test Plan]
$ sudo apt update && sudo apt dist-upgrade -y
$ sudo apt install swtpm apparmor -y
$ mkdir /tmp/myvtpm
# Before fix
$ sudo modprobe tpm_vtpm_proxy
$ sudo swtpm chardev --vtpm-proxy --tpmstate dir=/tmp/myvtpm --tpm2 --ctrl type=tcp,port=2322
swtpm: Ioctl to create vtpm proxy failed: Operation not permitted
# After fix
$ sudo modprobe tpm_vtpm_proxy
$ sudo swtpm chardev --vtpm-proxy --tpmstate dir=/tmp/myvtpm --tpm2 --ctrl type=tcp,port=2322
New TPM device: /dev/tpm1 (major/minor = 253/1)
[Where problems could occur]
This change will allow swtpm to access various kernel modules by
default. So if malicious code were to exist within swtpm, then it
would have far greater access when running with super user
permissions.
Likewise, with a change to the apparmor profile, a conflict will occur
on update for users that modified their profile directly.
[Other Info]
The issue was fixed in oracular in 0.7.3-0ubuntu7.
[Original Description]
Based on the upstream discussion here -
https://github.com/stefanberger/swtpm/discussions/866 - certain
features of swtpm require access to kernel modules to work. For
example, using --vtpm-proxy requires the tpm_vtpm_proxy module. This
should work by default, and is fixed by adding capability sys_admin to
the apparmor profile.
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