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Accepting request 764685 from Virtualization:containers

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CVE-2019-19921

OBS-URL: https://build.opensuse.org/request/show/764685
OBS-URL: https://build.opensuse.org/package/show/openSUSE:Factory/runc?expand=0&rev=25
This commit is contained in:
Dominique Leuenberger 2020-01-16 17:19:36 +00:00 committed by Git OBS Bridge
commit 0cad9de1a9
3 changed files with 62 additions and 2 deletions
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50
CVE-2019-19921.patch Normal file
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@ -0,0 +1,50 @@
From 9975f5238a792586bfa3e36e4c66a8d1154b44ac Mon Sep 17 00:00:00 2001
From: Aleksa Sarai <asarai@suse.de>
Date: Sat, 21 Dec 2019 23:40:17 +1100
Subject: [PATCH] rootfs: do not permit /proc mounts to non-directories
mount(2) will blindly follow symlinks, which is a problem because it
allows a malicious container to trick runc into mounting /proc to an
entirely different location (and thus within the attacker's control for
a rename-exchange attack).
This is just a hotfix (to "stop the bleeding"), and the more complete
fix would be finish libpathrs and port runc to it (to avoid these types
of attacks entirely, and defend against a variety of other /proc-related
attacks). It can be bypased by someone having "/" be a volume controlled
by another container.
Fixes: CVE-2019-19921
Signed-off-by: Aleksa Sarai <asarai@suse.de>
---
libcontainer/rootfs_linux.go | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/libcontainer/rootfs_linux.go b/libcontainer/rootfs_linux.go
index 291021440a1a..6bc0747f9f7e 100644
--- a/libcontainer/rootfs_linux.go
+++ b/libcontainer/rootfs_linux.go
@@ -299,6 +299,20 @@ func mountToRootfs(m *configs.Mount, rootfs, mountLabel string, enableCgroupns b
switch m.Device {
case "proc", "sysfs":
+ // If the destination already exists and is not a directory, we remove
+ // it. This is to avoid mounting through a symlink or similar -- which
+ // has been a "fun" attack scenario in the past.
+ // TODO: This won't be necessary once we switch to libpathrs and we can
+ // stop all of these symlink-exchange attacks.
+ if fi, err := os.Lstat(dest); err != nil {
+ if !os.IsNotExist(err) {
+ return err
+ }
+ } else if fi.Mode()&os.ModeDir == 0 {
+ if err := os.Remove(dest); err != nil {
+ return err
+ }
+ }
if err := os.MkdirAll(dest, 0755); err != nil {
return err
}
--
2.24.1

6
runc.changes
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@ -1,3 +1,9 @@
-------------------------------------------------------------------
Tue Jan 14 04:44:36 UTC 2020 - Aleksa Sarai <asarai@suse.com>
- Add backported fix for CVE-2019-19921. bsc#1160452
+ CVE-2019-19921.patch
-------------------------------------------------------------------
Sat Oct 5 11:40:13 UTC 2019 - Aleksa Sarai <asarai@suse.com>

8
runc.spec
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@ -1,7 +1,7 @@
#
# spec file for package runc
#
# Copyright (c) 2019 SUSE LINUX GmbH, Nuernberg, Germany.
# Copyright (c) 2020 SUSE LLC
#
# All modifications and additions to the file contributed by third parties
# remain the property of their copyright owners, unless otherwise agreed
@ -46,11 +46,13 @@ Release: 0
Summary: Tool for spawning and running OCI containers
License: Apache-2.0
Group: System/Management
Url: https://github.com/opencontainers/runc
URL: https://github.com/opencontainers/runc
Source0: https://github.com/opencontainers/runc/releases/download/v%{_version}/runc.tar.xz#/runc-%{_version}.tar.xz
Source1: https://github.com/opencontainers/runc/releases/download/v%{_version}/runc.tar.xz.asc#/runc-%{_version}.tar.xz.asc
Source2: runc.keyring
Source3: runc-rpmlintrc
# FIX-UPSTREAM: Backport of https://github.com/opencontainers/runc/pull/2207.
Patch1: CVE-2019-19921.patch
BuildRequires: fdupes
BuildRequires: go-go-md2man
BuildRequires: golang(API) = %{go_version}
@ -85,6 +87,8 @@ Test package for runc. It contains the source code and the tests.
%prep
%setup -q -n %{name}-%{_version}
# CVE-2019-19921
%patch1 -p1
%build
# Do not use symlinks. If you want to run the unit tests for this package at