Previously --nofilesystem=host only removed specifically access to the
`host` permissions, and not necessarily other filesystems (like `home`
or `/some/path`). This isn't very useful to limit access because you
don't know what other filesystems the app may have access too.
We change this to mean that `--nofilesystem=host` removes *all* filesystem
access from the parent layer, and `--nofilesystem=home` removes all
file access to the homedir and paths inside it.
The available layers are, in order:
* app permissions
* overrides
* commandline args
This allows you to start from scratch with the filesystem permissions
in the overrides or the commandline. This is a small change in
behaviour, but not a lot of things use --nofilesystem, and the ones
that do probably expects this behaviour.
(cherry picked from commit e2c8863fb62301cb05c64bbb32b04446e88ce11a)
This tests for invalid metadata, missing xa.metadata and mismatched
values in xa.metadata and the real metadata, including the embedded
null leading to the hidden permissions of CVE-2021-43860.
(cherry picked from commit 2c2ce58c54b3e6c62f9c21c15efa0ba22f4bc09b)
If we have a bundle without metadata we wouldn't properly present
the permissions in the transaction.
(cherry picked from commit b250541302187ff2209b0bb1295e8223d0af860f)
This was disables a long time ago because the fedora remotes didn't
contain metadata, but that has been added since then. Requiring fixes
a security concern where an app claims to require no permissions (by
having no metadata in commit) but then actually requires permissions
in the installed app.
(cherry picked from commit f0f3a35f404b5bd533186095db055f8b3d135576)
If we fail to parse xa.metadata from the summary cache or the commit
xa.metadata we fail the resolve.
If xa.metadata is missing in the commit we fail the resolve (it is
always set in the summary cache, because summary update converts
missing xa.metadata to "", so we either get that, or cache miss which
leads to resolving from the commit.
This means that op->resolved_metadata is always set during install and
updates, which means we will show the app permissions. The transaction
will also always make sure that this data actually matches what gets
deployed.
Before this change an invalid metadata in the summary cache could lead
to a NULL resolved_metadata, which means we wouldn't print the app
permissions, yet we would still deploy some metadata file that could
have permissions. (NOTE: It would fail to deploy unless the
xa.metadata in the commit matched the metadata file, but in this
corner case we would't compare the summary and commit metadata, so
they may differ.)
(cherry picked from commit 5036bca4214d5b77e884dec42e36496a06e74081)
In particular, if a null terminator is placed inside the metadata file,
Flatpak will only compare the text *before* it to the value of
xa.metadata, but the full file will be parsed when permissions are set
at runtime. This means that any app can include a null terminator in its
permissions metadata, and Flatpak will only show the user the
permissions *preceding* the terminator during install, but the
permissions *after* the terminator are applied at runtime.
Fixes GHSA-qpjc-vq3c-572j / CVE-2021-43860
Signed-off-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>
(cherry picked from commit c9c3a667c09a846c0b230cf1cc8ed330028aa03c)
This was incorrectly looking at errno instead of -r.
Fixes: 0b38b0f0 "run: Handle unknown syscalls as intended"
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit 3fc8c67267)
(cherry picked from commit 97e128c2c1)
The error-handling here was
if (r < 0 && r == -EFAULT)
but Alex says it was almost certainly intended to be
if (r < 0 && r != -EFAULT)
so that syscalls not known to libseccomp are not a fatal error.
Instead of literally making that change, emit a debug message on -EFAULT
so we can see what is going on.
This temporarily weakens our defence against CVE-2021-41133
(GHSA-67h7-w3jq-vh4q) in order to avoid regressions: if the installed
version of libseccomp does not know about the recently-added syscalls,
but the kernel does, then we will not prevent non-native executables
from using those syscalls.
Resolves: https://github.com/flatpak/flatpak/issues/4458
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit d419fa6703)
The soup backend and the curl backend give slightly different error
messages, so we need to tweak the 404 assert check to match both.
(cherry picked from commit 9914dff925)
If we don't allow pivot_root() then there seems no reason why we should
allow chroot().
Partially fixes GHSA-67h7-w3jq-vh4q.
Signed-off-by: Simon McVittie <smcv@collabora.com>
If we don't allow mounting filesystems, we shouldn't allow unmounting
either.
Partially fixes GHSA-67h7-w3jq-vh4q.
Signed-off-by: Simon McVittie <smcv@collabora.com>
If we don't allow unshare() or clone() with CLONE_NEWUSER, we also
shouldn't allow joining an existing (but different) namespace.
Partially fixes GHSA-67h7-w3jq-vh4q.
Signed-off-by: Simon McVittie <smcv@collabora.com>
If we don't allow mount() then we shouldn't allow these either.
Partially fixes GHSA-67h7-w3jq-vh4q.
Thanks: an anonymous reporter
Signed-off-by: Simon McVittie <smcv@collabora.com>
clone3() can be used to implement clone() with CLONE_NEWUSER, allowing
a sandboxed process to get CAP_SYS_ADMIN in a new namespace and
manipulate its root directory. We need to block this so that AF_UNIX-based
socket servers (X11, Wayland, etc.) can rely on
/proc/PID/root/.flatpak-info existing for all Flatpak-sandboxed apps.
Partially fixes GHSA-67h7-w3jq-vh4q.
Thanks: an anonymous reporter
Signed-off-by: Simon McVittie <smcv@collabora.com>
Historically, syscalls could take arbitrarily-different values on
different architectures, but new syscalls are added with syscall numbers
that align on each architecture.
Signed-off-by: Simon McVittie <smcv@collabora.com>
At the moment, if we block a syscall we always make it fail with EPERM,
but this is risky: user-space libraries can start to use new replacements
for old syscalls at any time, and will often treat EPERM as a fatal error.
For new syscalls, we should make the syscall fail with ENOSYS, which is
indistinguishable from running on an older kernel and will cause fallback
to an older implementation, for example clone3() to clone().
In future we should probably move from EPERM to ENOSYS for some of the
syscalls we already block, but for now keep the status quo.
This is a prerequisite for fixing the vulnerability tracked as
GHSA-67h7-w3jq-vh4q.
Signed-off-by: Simon McVittie <smcv@collabora.com>
These checks were broken in commit d762a2f, as the commit failed to
consider the fact that `flatpak_dir_check_parental_controls()` is run
both in the `flatpak` CLI process run by the user, but also in the
`flatpak-system-helper` process which always runs as root, and which
handles any installations done on the system repository.
As a result, parental controls were not working for the system
repository.
Fix that by limiting the scope of the check to only pass if running
without the system helper. flatpak calls from root never go through the
system helper.
Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Fixes: #4418
For reasons unknown, libarchive appears to generate broken gnutar format
tar archives when the archive contains files that are larger than 2 GB.
This commit switches to the pax format to work this around.
This should be a better default as it also removes 256 char filename
length limitation and matches what other libraries are doing, e.g.
Python 3.8 switched to the pax format by default as well.
See https://pagure.io/fedora-infrastructure/issue/9840
(cherry picked from commit b90d638601)
If we do, it interferes with xdg-dbus-proxy, causing test failure under
some circumstances: the test passes on a development system, but fails
when run on a qemu virtual machine in Debian's autopkgtest framework.
Fixes: 6e5b02e2 "run: Don't let XDG_RUNTIME_DIR from user override the value we set"
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit 7bf6ecfaa2)
We use `bwrap --setenv XDG_RUNTIME_DIR` to set it to `/run/user/UID`,
regardless of what it is on the host system, but the changes made
to resolve CVE-2021-21261 unintentionally broke this by overwriting it
with the user's XDG_RUNTIME_DIR.
In practice this worked for most people, who either have
XDG_RUNTIME_DIR set to the same value we use (which is the conventional
setup from systemd-logind and elogind), or entirely unset (if they do not
have systemd-logind or elogind). However, it broke Wayland and other
XDG_RUNTIME_DIR-based protocols for people who intentionally set up an
XDG_RUNTIME_DIR that is different.
Fixes: 6d1773d2 "run: Convert all environment variables into bwrap arguments"
Resolves: https://github.com/flatpak/flatpak/issues/4372
Signed-off-by: Simon McVittie <smcv@collabora.com>
For updates in remotes with a local (file:) uri we just do a deploy
with a LOCAL_PULL flag set and an empty arg_repo_path. However, our
arg_repo_path checking at some point seemed to stop properly handling
the case where it is empty. I got it to report "No such file" wich
broke the tests.
(cherry picked from commit 49e8bfcea5)
Fixes: #4339
Distributions run these tests on other architectures, but hard-coding
x86_64 to look for in output dooms that to failure.
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit ba381ae936)
Just because we can allocate a new, unused fd in the portal's fd space,
that doesn't mean that fd number is going to be unused in the child
process's fd space: we might need to remap it.
Resolves: flatpak/flatpak#4286
Fixes: aeb6a7ab "portal: Convert --env in extra-args into --env-fd"
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit 526dae9241)
This will allow us to add additional mapping entries for fds to be
used internally by `flatpak run`, in particular --env-fd.
Defer the second pass through the fd array until the last possible
moment, so that any extra fds we want to add (like the --env-fd) have
already been added by then.
Helps: flatpak/flatpak#4286
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit a09d07f085)
Otherwise we'll run out of file descriptors eventually, when starting
a sufficiently large number of subsandboxes.
Resolves: flatpak/flatpak#4285
Fixes: aeb6a7ab "portal: Convert --env in extra-args into --env-fd"
Signed-off-by: Simon McVittie <smcv@collabora.com>
(cherry picked from commit f2fbc75827)
For whatever reason parts of mono is installed, but the repo is not
configured so there is a version conflict on update:
libglib2.0-cil is already the newest version (2.12.45-0xamarin19+ubuntu1604b1).
libglib2.0-cil set to manually installed.
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
libglib2.0-cil-dev : Depends: libglib2.0-cil (= 2.12.10-6) but 2.12.45-0xamarin19+ubuntu1604b1 is to be installed
E: Unable to correct problems, you have held broken packages.
(cherry picked from commit b6d5e20857)
Currently the create-usb command copies extra-data flatpaks such as the
org.freedesktop.Platform.openh264 runtime extension along with normal
non-extra-data content. This is an issue because on the computer
installing from the USB it will attempt to get the extra-data content
from the URI specified in the commit metadata, which will fail if the
URI is a resource on the Internet and the computer is offline.
Instead, have create-usb omit such refs. If it was specified explicitly
this is treated as a hard error and if it's a dependency it's treated as
a warning, so that e.g. org.freedesktop.Platform can still be copied to
a USB and installed/updated offline. On the receiving end the absence of
org.freedesktop.Platform.openh264 will correctly not be treated as fatal
to the installation of org.freedesktop.Platform.
This issue was affecting offline updates of Endless OS, since such OS
updates include flatpaks along with the OS content.
For the (legally questionable) topic of properly supporting extra-data
distribution offline, see https://github.com/flatpak/flatpak/issues/969
(cherry picked from commit 0bf8cf9a08)
