On Wed, 2018-05-02 at 16:49 -0500, Eric W. Biederman wrote: > From: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > Date: Fri, 22 Dec 2017 15:32:35 +0100 > > The kernel should not calculate new hmacs for mounts done by > non-root users. Update evm_calc_hmac_or_hash() to refuse to > calculate new hmacs for mounts for non-init user namespaces. > > Cc: linux-integrity@xxxxxxxxxxxxxxx > Cc: linux-security-module@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: James Morris <james.l.morris@xxxxxxxxxx> > Cc: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx> > Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx> > Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > Signed-off-by: Dongsu Park <dongsu@xxxxxxxxxx> > Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx> > --- > > Mimi this patch has been floating around for a while and it appears to > be the only piece missing from the vfs to make unprivileged mounts safe > (at least semantically). Do you want to merge this through your integrity > tree or should merge this through my userns tree? Matthew's EVM patches don't conflict with this change, so either way is fine. Mimi > > security/integrity/evm/evm_crypto.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > > diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c > index a46fba322340..facf9cdd577d 100644 > --- a/security/integrity/evm/evm_crypto.c > +++ b/security/integrity/evm/evm_crypto.c > @@ -200,7 +200,8 @@ static int evm_calc_hmac_or_hash(struct dentry *dentry, > int size; > bool ima_present = false; > > - if (!(inode->i_opflags & IOP_XATTR)) > + if (!(inode->i_opflags & IOP_XATTR) || > + inode->i_sb->s_user_ns != &init_user_ns) > return -EOPNOTSUPP; > > desc = init_desc(type);
