shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-07 19:30:30 +09:00
Code Issues Packages Projects Releases Wiki Activity

UPSTREAM: cgroup-v1: Require capabilities to set release_agent

Browse Source 
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: 81a6a5cdd2 ("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>
(cherry picked from commit 24f6008564)
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: If663568d24f781c58c882d69a5b81a9327c0e6fe
This commit is contained in:
Eric W. Biederman
2022-01-20 11:04:01 -06:00
committed by Todd Kjos
parent 7e6f112beb
commit ee1e2de73c
1 changed files with 14 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

14
kernel/cgroup/cgroup-v1.c
View File

@@ -548,6 +548,14 @@ static ssize_t cgroup_release_agent_write(struct kernfs_open_file *of,
BUILD_BUG_ON(sizeof(cgrp->root->release_agent_path) < PATH_MAX); 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); cgrp = cgroup_kn_lock_live(of->kn, false);
if (!cgrp) if (!cgrp)
return -ENODEV; return -ENODEV;
@@ -961,6 +969,12 @@ int cgroup1_parse_param(struct fs_context *fc, struct fs_parameter *param)
/* Specifying two release agents is forbidden */ /* Specifying two release agents is forbidden */
if (ctx->release_agent) if (ctx->release_agent)
return invalfc(fc, "release_agent respecified"); return invalfc(fc, "release_agent respecified");
/*
* Release agent gets called with all capabilities,
* require capabilities to set release agent.
*/
if ((fc->user_ns != &init_user_ns) || !capable(CAP_SYS_ADMIN))
return invalfc(fc, "Setting release_agent not allowed");
ctx->release_agent = param->string; ctx->release_agent = param->string;
param->string = NULL; param->string = NULL;
break; break;