Commit 7b0b78df authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'userns-for-v5.12' of... 

Merge branch 'userns-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace

Pull user namespace update from Eric Biederman:
 "There are several pieces of active development, but only a single
  change made it through the gauntlet to be ready for v5.12. That change
  is tightening up the semantics of the v3 capabilities xattr. It is
  just short of being a bug-fix/security issue as no user space is known
  to even generate the problem case"

* 'userns-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  capabilities: Don't allow writing ambiguous v3 file capabilities
parents ac9e806c 95ebabde

security/commoncap.c

+11 −1
Original line number Diff line number Diff line
@@ -500,7 +500,8 @@ int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size) 
	__u32 magic, nsmagic;

	struct inode *inode = d_backing_inode(dentry);

	struct user_namespace *task_ns = current_user_ns(),

		*fs_ns = inode->i_sb->s_user_ns;

		*fs_ns = inode->i_sb->s_user_ns,

		*ancestor;

	kuid_t rootid;

	size_t newsize;
@@ -523,6 +524,15 @@ int cap_convert_nscap(struct dentry *dentry, const void **ivalue, size_t size) 
	if (nsrootid == -1)

		return -EINVAL;



	/*

	 * Do not allow allow adding a v3 filesystem capability xattr

	 * if the rootid field is ambiguous.

	 */

	for (ancestor = task_ns->parent; ancestor; ancestor = ancestor->parent) {

		if (from_kuid(ancestor, rootid) == 0)

			return -EINVAL;

	}



	newsize = sizeof(struct vfs_ns_cap_data);

	nscap = kmalloc(newsize, GFP_ATOMIC);

	if (!nscap)