From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Wed, 9 Feb 2022 06:03:29 +0000 (+0100)
Subject: 4.19-stable patches
X-Git-Tag: v4.9.301~20
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=702117eb736392dcdd16af7c3a9a3d738c176a8b;p=thirdparty%2Fkernel%2Fstable-queue.git

4.19-stable patches

added patches:
	cgroup-v1-require-capabilities-to-set-release_agent.patch
---

diff --git a/queue-4.19/cgroup-v1-require-capabilities-to-set-release_agent.patch b/queue-4.19/cgroup-v1-require-capabilities-to-set-release_agent.patch
new file mode 100644
index 00000000000..e517a9e61dd
--- /dev/null
+++ b/queue-4.19/cgroup-v1-require-capabilities-to-set-release_agent.patch
@@ -0,0 +1,80 @@
+From 24f6008564183aa120d07c03d9289519c2fe02af Mon Sep 17 00:00:00 2001
+From: "Eric W. Biederman" <ebiederm@xmission.com>
+Date: Thu, 20 Jan 2022 11:04:01 -0600
+Subject: cgroup-v1: Require capabilities to set release_agent
+
+From: Eric W. Biederman <ebiederm@xmission.com>
+
+commit 24f6008564183aa120d07c03d9289519c2fe02af upstream.
+
+The cgroup release_agent is called with call_usermodehelper.  The function
+call_usermodehelper starts the release_agent with a full set fo capabilities.
+Therefore require capabilities when setting the release_agaent.
+
+Reported-by: Tabitha Sable <tabitha.c.sable@gmail.com>
+Tested-by: Tabitha Sable <tabitha.c.sable@gmail.com>
+Fixes: 81a6a5cdd2c5 ("Task Control Groups: automatic userspace notification of idle cgroups")
+Cc: stable@vger.kernel.org # v2.6.24+
+Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
+Signed-off-by: Tejun Heo <tj@kernel.org>
+[mkoutny: Adjust for pre-fs_context, duplicate mount/remount check, drop log messages.]
+Acked-by: Michal Koutný <mkoutny@suse.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ kernel/cgroup/cgroup-v1.c |   24 ++++++++++++++++++++++++
+ 1 file changed, 24 insertions(+)
+
+--- a/kernel/cgroup/cgroup-v1.c
++++ b/kernel/cgroup/cgroup-v1.c
+@@ -577,6 +577,14 @@ static ssize_t cgroup_release_agent_writ
+ 
+ 	BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX);
+ 
++	/*
++	 * Release agent gets called with all capabilities,
++	 * require capabilities to set release agent.
++	 */
++	if ((of->file->f_cred->user_ns != &init_user_ns) ||
++	    !capable(CAP_SYS_ADMIN))
++		return -EPERM;
++
+ 	cgrp = cgroup_kn_lock_live(of->kn, false);
+ 	if (!cgrp)
+ 		return -ENODEV;
+@@ -1048,6 +1056,7 @@ static int cgroup1_remount(struct kernfs
+ {
+ 	int ret = 0;
+ 	struct cgroup_root *root = cgroup_root_from_kf(kf_root);
++	struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
+ 	struct cgroup_sb_opts opts;
+ 	u16 added_mask, removed_mask;
+ 
+@@ -1061,6 +1070,12 @@ static int cgroup1_remount(struct kernfs
+ 	if (opts.subsys_mask != root->subsys_mask || opts.release_agent)
+ 		pr_warn("option changes via remount are deprecated (pid=%d comm=%s)\n",
+ 			task_tgid_nr(current), current->comm);
++	/* See cgroup1_mount release_agent handling */
++	if (opts.release_agent &&
++	    ((ns->user_ns != &init_user_ns) || !capable(CAP_SYS_ADMIN))) {
++		ret = -EINVAL;
++		goto out_unlock;
++	}
+ 
+ 	added_mask = opts.subsys_mask & ~root->subsys_mask;
+ 	removed_mask = root->subsys_mask & ~opts.subsys_mask;
+@@ -1224,6 +1239,15 @@ struct dentry *cgroup1_mount(struct file
+ 		ret = -EPERM;
+ 		goto out_unlock;
+ 	}
++	/*
++	 * Release agent gets called with all capabilities,
++	 * require capabilities to set release agent.
++	 */
++	if (opts.release_agent &&
++	    ((ns->user_ns != &init_user_ns) || !capable(CAP_SYS_ADMIN))) {
++		ret = -EINVAL;
++		goto out_unlock;
++	}
+ 
+ 	root = kzalloc(sizeof(*root), GFP_KERNEL);
+ 	if (!root) {
diff --git a/queue-4.19/series b/queue-4.19/series
new file mode 100644
index 00000000000..cf94f67b753
--- /dev/null
+++ b/queue-4.19/series
@@ -0,0 +1 @@
+cgroup-v1-require-capabilities-to-set-release_agent.patch