| Message ID | dacfb329-de66-d0cf-dcf9-f030ea1370de@schaufler-ca.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Smack: Handle io_uring kernel thread privileges. | expand |
Casey Schaufler <casey@schaufler-ca.com> writes: > Smack assumes that kernel threads are privileged for smackfs > operations. This was necessary because the credential of the > kernel thread was not related to a user operation. With io_uring > the credential does reflect a user's rights and can be used. Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> > > Suggested-by: Jens Axboe <axboe@kernel.dk> > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> > --- > security/smack/smack_access.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c > index efe2406a3960..7eabb448acab 100644 > --- a/security/smack/smack_access.c > +++ b/security/smack/smack_access.c > @@ -688,9 +688,10 @@ bool smack_privileged_cred(int cap, const struct cred *cred) > bool smack_privileged(int cap) > { > /* > - * All kernel tasks are privileged > + * Kernel threads may not have credentials we can use. > + * The io_uring kernel threads do have reliable credentials. > */ > - if (unlikely(current->flags & PF_KTHREAD)) > + if ((current->flags & (PF_KTHREAD | PF_IO_WORKER)) == PF_KTHREAD) > return true; > > return smack_privileged_cred(cap, current_cred());
On 12/17/20 6:12 PM, Casey Schaufler wrote: > Smack assumes that kernel threads are privileged for smackfs > operations. This was necessary because the credential of the > kernel thread was not related to a user operation. With io_uring > the credential does reflect a user's rights and can be used. Acked-by: Jens Axboe <axboe@kernel.dk>
diff --git a/security/smack/smack_access.c b/security/smack/smack_access.c index efe2406a3960..7eabb448acab 100644 --- a/security/smack/smack_access.c +++ b/security/smack/smack_access.c @@ -688,9 +688,10 @@ bool smack_privileged_cred(int cap, const struct cred *cred) bool smack_privileged(int cap) { /* - * All kernel tasks are privileged + * Kernel threads may not have credentials we can use. + * The io_uring kernel threads do have reliable credentials. */ - if (unlikely(current->flags & PF_KTHREAD)) + if ((current->flags & (PF_KTHREAD | PF_IO_WORKER)) == PF_KTHREAD) return true; return smack_privileged_cred(cap, current_cred());
Smack assumes that kernel threads are privileged for smackfs operations. This was necessary because the credential of the kernel thread was not related to a user operation. With io_uring the credential does reflect a user's rights and can be used. Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> --- security/smack/smack_access.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)