From: Wolfgang Bumiller <w.bumiller@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH container] disable btrfs ioctl in user namespaces
Date: Thu, 24 Jun 2021 16:09:17 +0200 [thread overview]
Message-ID: <20210624140917.14556-1-w.bumiller@proxmox.com> (raw)
Changes the seccomp profile to return EPERM on every btrfs
ioctl.
Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
src/PVE/LXC.pm | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/src/PVE/LXC.pm b/src/PVE/LXC.pm
index 93286f6..393da1b 100644
--- a/src/PVE/LXC.pm
+++ b/src/PVE/LXC.pm
@@ -435,6 +435,15 @@ sub make_seccomp_config {
my $rules = {
keyctl => ['errno 38'],
+
+ # Disable btrfs ioctrls since they don't work particularly well in user namespaces.
+ # Particularly, without the mount option to enable rmdir removing snapshots, user
+ # namespaces can create snapshots but neither `show` or `delete` them, which is quite
+ # horrible, so for now, just disable this entirely:
+ #
+ # BTRFS_IOCTL_MAGIC 0x94, _IOC type shift is 8,
+ # so `(req & 0xFF00) == 0x9400` is a btrfs ioctl and gets an EPERM
+ ioctl => ['errno 1 [1,0x9400,SCMP_CMP_MASKED_EQ,0xff00]'],
};
my $raw_conf = '';
--
2.30.2
next reply other threads:[~2021-06-24 14:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-24 14:09 Wolfgang Bumiller [this message]
2021-06-24 14:43 ` [pve-devel] applied: " Thomas Lamprecht
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