diff options
| -rw-r--r-- | kernel/cgroup/cgroup.c | 57 |
1 files changed, 33 insertions, 24 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index dbfd7028b1c6..d48069ee84c2 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -2363,27 +2363,12 @@ static int cgroup_procs_write_permission(struct task_struct *task, struct cgroup *dst_cgrp, struct kernfs_open_file *of) { - int ret = 0; - - if (cgroup_on_dfl(dst_cgrp)) { - struct super_block *sb = of->file->f_path.dentry->d_sb; - struct cgroup *cgrp; - struct inode *inode; - - spin_lock_irq(&css_set_lock); - cgrp = task_cgroup_from_root(task, &cgrp_dfl_root); - spin_unlock_irq(&css_set_lock); - - while (!cgroup_is_descendant(dst_cgrp, cgrp)) - cgrp = cgroup_parent(cgrp); + struct super_block *sb = of->file->f_path.dentry->d_sb; + struct cgroup *src_cgrp, *com_cgrp; + struct inode *inode; + int ret; - ret = -ENOMEM; - inode = kernfs_get_inode(sb, cgrp->procs_file.kn); - if (inode) { - ret = inode_permission(inode, MAY_WRITE); - iput(inode); - } - } else { + if (!cgroup_on_dfl(dst_cgrp)) { const struct cred *cred = current_cred(); const struct cred *tcred = get_task_cred(task); @@ -2391,14 +2376,38 @@ static int cgroup_procs_write_permission(struct task_struct *task, * even if we're attaching all tasks in the thread group, * we only need to check permissions on one of them. */ - if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) && - !uid_eq(cred->euid, tcred->uid) && - !uid_eq(cred->euid, tcred->suid)) + if (uid_eq(cred->euid, GLOBAL_ROOT_UID) || + uid_eq(cred->euid, tcred->uid) || + uid_eq(cred->euid, tcred->suid)) + ret = 0; + else ret = -EACCES; + put_cred(tcred); + return ret; } - return ret; + /* find the source cgroup */ + spin_lock_irq(&css_set_lock); + src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root); + spin_unlock_irq(&css_set_lock); + + /* and the common ancestor */ + com_cgrp = src_cgrp; + while (!cgroup_is_descendant(dst_cgrp, com_cgrp)) + com_cgrp = cgroup_parent(com_cgrp); + + /* %current should be authorized to migrate to the common ancestor */ + inode = kernfs_get_inode(sb, com_cgrp->procs_file.kn); + if (!inode) + return -ENOMEM; + + ret = inode_permission(inode, MAY_WRITE); + iput(inode); + if (ret) + return ret; + + return 0; } /* |