* [PATCH] Smack: Handle io_uring kernel thread privileges.
[not found] <dacfb329-de66-d0cf-dcf9-f030ea1370de.ref@schaufler-ca.com>
@ 2020-12-18 1:12 ` Casey Schaufler
2020-12-21 19:55 ` Eric W. Biederman
2020-12-22 2:05 ` Jens Axboe
0 siblings, 2 replies; 3+ messages in thread
From: Casey Schaufler @ 2020-12-18 1:12 UTC (permalink / raw)
To: SMACK-discuss, Linux Security Module list
Cc: Jens Axboe, Eric W. Biederman, Casey Schaufler, LKML
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(-)
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());
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] Smack: Handle io_uring kernel thread privileges.
2020-12-18 1:12 ` [PATCH] Smack: Handle io_uring kernel thread privileges Casey Schaufler
@ 2020-12-21 19:55 ` Eric W. Biederman
2020-12-22 2:05 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Eric W. Biederman @ 2020-12-21 19:55 UTC (permalink / raw)
To: Casey Schaufler
Cc: SMACK-discuss, Linux Security Module list, Jens Axboe, LKML
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());
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Smack: Handle io_uring kernel thread privileges.
2020-12-18 1:12 ` [PATCH] Smack: Handle io_uring kernel thread privileges Casey Schaufler
2020-12-21 19:55 ` Eric W. Biederman
@ 2020-12-22 2:05 ` Jens Axboe
1 sibling, 0 replies; 3+ messages in thread
From: Jens Axboe @ 2020-12-22 2:05 UTC (permalink / raw)
To: Casey Schaufler, SMACK-discuss, Linux Security Module list
Cc: Eric W. Biederman, LKML
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>
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-12-22 2:06 UTC | newest]
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2020-12-18 1:12 ` [PATCH] Smack: Handle io_uring kernel thread privileges Casey Schaufler
2020-12-21 19:55 ` Eric W. Biederman
2020-12-22 2:05 ` Jens Axboe
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