Arcvm needs this ioctl for looking up the project id of an inode.
BUG=b:157189438
TEST=Call the ioctl inside a vm and verify that it succeeds
Change-Id: Ib178cf32b09056f9b1e9acedb49de068d5525a66
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2214964
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Matthias Springer <springerm@chromium.org>
Reviewed-by: Zach Reizner <zachr@chromium.org>
Reviewed-by: Stephen Barber <smbarber@chromium.org>
When creating a file or directory the virtio-fs server changes its
effective uid and gid to the uid and gid of the process that made the
call. This ensures that the file or directory has the correct owner and
group when it is created and also serves as an access check to ensure
that the process that made the call has permission to modify the parent
directory.
However, this causes an EACCES error when the following conditions are
met:
* The parent directory has g+rw permissions with gid A
* The process has gid B but has A in its list of supplementary groups
In this case the fuse context only contains gid B, which doesn't have
permission to modify the parent directory.
Unfortunately there's no way for us to detect this on the server side so
instead we just have to rely on the permission checks carried out by the
kernel driver. If the server receives a create call, then assume that
the kernel has verified that the process is allowed to create that
file/directory and just create it without changing the server thread's
uid and gid.
Additionally, in order to ensure that a newly created file appears
atomically in the parent directory with the proper owner and group,
change the create implementation to use `O_TMPFILE` and `linkat` as
described in the open(2) manpage. There is no `O_TMPFILE` equivalent
for directories so create a "hidden" directory with a randomly generated
name, modify the uid/gid and mode, and then rename it into place.
BUG=b:156696212
TEST=tast run $DUT vm.Virtiofs
TEST=Create a test directory with group wayland and permissions g+rw.
Then run `su -s /bin/bash -c 'touch ${dir}/foo' - crosvm` and
`su -s /bin/bash -c 'mkdir ${dir}/bar' - crosvm`.
Change-Id: If5fbcb1b011664c7c1ac29542a2f90d129c34962
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2217534
Reviewed-by: Chirantan Ekbote <chirantan@chromium.org>
Commit-Queue: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: Chirantan Ekbote <chirantan@chromium.org>
Using the `open_inode` method on an fd for a symlink results in the
kernel returning -ELOOP. Since there are no `*at` methods for extended
attributes, manually read the path for the file and then use the
l{get,set,list,remove}xattr method on the returned path.
BUG=b:136128512
TEST=boot arcvm with virtio-fs and selinux enabled
Change-Id: I2fde57db8a075838a3a877309f6cf89059f19258
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2120763
Auto-Submit: Chirantan Ekbote <chirantan@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Stephen Barber <smbarber@chromium.org>
Reviewed-by: Stephen Barber <smbarber@chromium.org>
Minijail's policy compiler complains when there's multiple
unconditional rules for a syscall. In most cases the rules
are redundant to common_device.policy.
BUG=None
TEST=Ran compile_seccomp_policy.py until it stopped
complaining.
Change-Id: Ic43d1fd13f9c012641d71e526942229eb8b08ed4
Signed-off-by: Matt Delco <delco@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/2034024
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Dylan Reid <dgreid@chromium.org>
