From 0de0e610f6b359c52d4f8b02bac2963f4968c9d6 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 7 Jan 2015 14:28:26 -0600 Subject: mnt: Fail collect_mounts when applied to unmounted mounts [ Upstream commit cd4a40174b71acd021877341684d8bb1dc8ea4ae ] The only users of collect_mounts are in audit_tree.c In audit_trim_trees and audit_add_tree_rule the path passed into collect_mounts is generated from kern_path passed an audit_tree pathname which is guaranteed to be an absolute path. In those cases collect_mounts is obviously intended to work on mounted paths and if a race results in paths that are unmounted when collect_mounts it is reasonable to fail early. The paths passed into audit_tag_tree don't have the absolute path check. But are used to play with fsnotify and otherwise interact with the audit_trees, so again operating only on mounted paths appears reasonable. Avoid having to worry about what happens when we try and audit unmounted filesystems by restricting collect_mounts to mounts that appear in the mount tree. Fixes CVE-2015-4177. Upstream-Status: Backport Signed-off-by: "Eric W. Biederman" Signed-off-by: Sasha Levin Signed-off-by: Sona Sarmadi --- fs/namespace.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/namespace.c b/fs/namespace.c index 64837e3..8b60287 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -1675,8 +1675,11 @@ struct vfsmount *collect_mounts(struct path *path) { struct mount *tree; namespace_lock(); - tree = copy_tree(real_mount(path->mnt), path->dentry, - CL_COPY_ALL | CL_PRIVATE); + if (!check_mnt(real_mount(path->mnt))) + tree = ERR_PTR(-EINVAL); + else + tree = copy_tree(real_mount(path->mnt), path->dentry, + CL_COPY_ALL | CL_PRIVATE); namespace_unlock(); if (IS_ERR(tree)) return ERR_CAST(tree); -- cgit v0.11.2