** Also affects: apparmor (Ubuntu Plucky)
Importance: Undecided
Status: New
** Also affects: apparmor (Ubuntu Questing)
Importance: Undecided
Assignee: Maxime Bélair (mbelair)
Status: Fix Released
** Changed in: apparmor (Ubuntu Plucky)
Status: New => In Progress
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https://bugs.launchpad.net/bugs/2107455
Title:
segfault of lsblk s390x in containers due to apparmor
Status in Ubuntu on IBM z Systems:
Confirmed
Status in apparmor package in Ubuntu:
Fix Released
Status in apparmor source package in Plucky:
In Progress
Status in apparmor source package in Questing:
Fix Released
Bug description:
SRU Justification:
[ Impact ]
lsblk would segfault when run from a confined context due to missing
permissions on the binary execution path, and the lsblk profile need
rules to give m+r permissions for the binaries themselves.
[ Test Plan ]
* Add the following to a new file and use `apparmor_parser path/to/file` to
load it as a profile:
abi <abi/4.0>,
include <tunables/global>
profile allow_all {
allow all,
priority=1 /** px,
}
* Choose a subset of the applications confined by profiles under
profiles/apparmor.d modified by
debian/patches/ubuntu/profiles_ensure_access_to_attach_path.patch, and for each
selected application:
- Run `aa-exec -p allow_all -- lsblk`
- Verify that the application does not segfault on launch
- If application segfaults on launch only when run under confinement,
check for apparmor="DENIED" log entry denying read or mmap operations on the
binary path, and report verification test failure
[ Where problems could occur ]
The lsblk profile update loosens confinement on a profile. However, if
a user manually modified the installed profile, then the package
upgrade would cause conflicts, and rejection of the incoming changes
(either by hand during an interactive upgrade or automatically during
an batch unattended upgrade) would result in end users not getting the
packaged fix.
[ Other Info ]
__________
Hey,
while debugging bug 2107402 we found that there is more to fix.
Running lsblk in a container on s390x hits this:
[12064869.934674] audit: type=1400 audit(1744791155.353:111962):
apparmor="DENIED" operation="file_mmap" class="file"
namespace="root//lxd-p_<var-snap-lxd-common-lxd>" profile="lsblk"
name="/usr/bin/lsblk" pid=3286747 comm="lsblk" requested_mask="rm"
denied_mask="rm" fsuid=1000000 ouid=1000000
To the user it just segfaults.
root@p:~# lsblk
Segmentation fault
root@p:~# aa-disable lsblk
Disabling /usr/bin/lsblk.
root@p:~# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
loop0 7:0 0 93.8M 1 loop
loop1 7:1 0 94M 1 l
...
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