[PATCH v5 5/7] proc: instantiate only pids that we can ptrace on 'limit_pids=1' mount option
From: Alexey Gladkov <hidden>
Date: 2018-05-11 09:46:13
Also in:
linux-api, linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), proc filesystem, the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Djalal Harouni <redacted> If "limit_pids=1" mount option is set then do not instantiate pids that we can not ptrace. "limit_pids=1" means that procfs should only contain pids that the caller can ptrace. Cc: Kees Cook <redacted> Cc: Andy Lutomirski <luto@kernel.org> Signed-off-by: Djalal Harouni <redacted> --- fs/proc/base.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 6f084344..31baeef 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c@@ -3187,6 +3187,7 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsign unsigned tgid; struct proc_fs_info *fs_info = proc_sb(dir->i_sb); struct pid_namespace *ns = fs_info->pid_ns; + int limit_pids = proc_fs_limit_pids(fs_info); tgid = name_to_int(&dentry->d_name); if (tgid == ~0U)
@@ -3200,7 +3201,15 @@ struct dentry *proc_pid_lookup(struct inode *dir, struct dentry * dentry, unsign if (!task) goto out; + /* Limit procfs to only ptracable tasks */ + if (limit_pids == PROC_LIMIT_PIDS_PTRACE) { + cond_resched(); + if (!has_pid_permissions(fs_info, task, HIDEPID_NO_ACCESS)) + goto out_put_task; + } + result = proc_pid_instantiate(dir, dentry, task, NULL); +out_put_task: put_task_struct(task); out: return ERR_PTR(result);
--
2.10.5
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