Messages in this thread |  | | Date | Mon, 13 Jun 2022 08:46:49 -0500 | Subject | Re: [PATCH v3] cred: Propagate security_prepare_creds() error code | From | Frederick Lawler <> |
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Hi Eric,
On 6/9/22 6:18 PM, Eric Biggers wrote: > On Wed, Jun 08, 2022 at 10:09:42AM -0500, Frederick Lawler wrote: >> diff --git a/fs/aio.c b/fs/aio.c >> index 3c249b938632..5abbe88c3ca7 100644 >> --- a/fs/aio.c >> +++ b/fs/aio.c >> @@ -1620,6 +1620,8 @@ static void aio_fsync_work(struct work_struct *work) >> static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb, >> bool datasync) >> { >> + int err; >> + >> if (unlikely(iocb->aio_buf || iocb->aio_offset || iocb->aio_nbytes || >> iocb->aio_rw_flags)) >> return -EINVAL; >> @@ -1628,8 +1630,11 @@ static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb, >> return -EINVAL; >> >> req->creds = prepare_creds(); >> - if (!req->creds) >> - return -ENOMEM; >> + if (IS_ERR(req->creds)) { >> + err = PTR_ERR(req->creds); >> + req->creds = NULL; >> + return err; >> + } > > This part is a little ugly. How about doing: > > creds = prepare_creds(); > if (IS_ERR(creds)) > return PTR_ERR(creds); > req->creds = creds; >
I can do that, and same for below.
>> diff --git a/fs/exec.c b/fs/exec.c >> index 0989fb8472a1..02624783e40e 100644 >> --- a/fs/exec.c >> +++ b/fs/exec.c >> @@ -1468,15 +1468,19 @@ EXPORT_SYMBOL(finalize_exec); >> */ >> static int prepare_bprm_creds(struct linux_binprm *bprm) >> { >> + int err = -ERESTARTNOINTR; >> if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) >> - return -ERESTARTNOINTR; >> + return err; >> >> bprm->cred = prepare_exec_creds(); >> - if (likely(bprm->cred)) >> - return 0; >> + if (IS_ERR(bprm->cred)) { >> + err = PTR_ERR(bprm->cred); >> + bprm->cred = NULL; >> + mutex_unlock(¤t->signal->cred_guard_mutex); >> + return err; >> + } >> >> - mutex_unlock(¤t->signal->cred_guard_mutex); >> - return -ENOMEM; >> + return 0; >> } > > Similarly: > > static int prepare_bprm_creds(struct linux_binprm *bprm) > { > struct cred *cred; > > if (mutex_lock_interruptible(¤t->signal->cred_guard_mutex)) > return -ERESTARTNOINTR; > > cred = prepare_exec_creds(); > if (IS_ERR(cred)) { > mutex_unlock(¤t->signal->cred_guard_mutex); > return PTR_ERR(cred); > } > bprm->cred = cred; > return 0; > } > >> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c >> index eec72ca962e2..6cf75aa83b6c 100644 >> --- a/kernel/nsproxy.c >> +++ b/kernel/nsproxy.c >> @@ -311,6 +311,7 @@ static void put_nsset(struct nsset *nsset) >> >> static int prepare_nsset(unsigned flags, struct nsset *nsset) >> { >> + int err = -ENOMEM; >> struct task_struct *me = current; >> >> nsset->nsproxy = create_new_namespaces(0, me, current_user_ns(), me->fs); >> @@ -324,6 +325,12 @@ static int prepare_nsset(unsigned flags, struct nsset *nsset) >> if (!nsset->cred) >> goto out; >> >> + if (IS_ERR(nsset->cred)) { >> + err = PTR_ERR(nsset->cred); >> + nsset->cred = NULL; >> + goto out; >> + } > > Why is the NULL check above being kept? >
In the branch prior:
if (flags & CLONE_NEWUSER) { nsset->cred = prepare_creds(); else nsset->cred = current_cred();
I don't see cases where others are checking for null after current_cred(), therefore I can remove that check.
> Also, drivers/crypto/ccp/sev-dev.c needs to be updated. >
Nice catch! I clearly missed addition after the merge window.
> - Eric
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