* [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it
@ 2022-03-25 11:21 Petr Vorel
2022-03-25 13:29 ` Eric W. Biederman
2022-03-25 15:37 ` Christian Brauner
0 siblings, 2 replies; 5+ messages in thread
From: Petr Vorel @ 2022-03-25 11:21 UTC (permalink / raw)
To: linux-kernel
Cc: Petr Vorel, Christian Brauner, Alexey Gladkov,
Eric W . Biederman, Serge E . Hallyn, Vasily Averin,
Andrew Morton
Move MAX_PID_NS_LEVEL to ns_common.h and reuse it in check in
user_namespace.c.
Signed-off-by: Petr Vorel <pvorel@suse.cz>
---
Hi Christian, all,
I don't see putting MAX_PID_NS_LEVEL into ns_common.h as an elegant
solution but IMHO better than use a hardwired number or redefinition in
user_namespace.h.
Kind regards,
Petr
include/linux/ns_common.h | 3 +++
include/linux/pid_namespace.h | 3 ---
kernel/user_namespace.c | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index 0f1d024bd958..173fab9dadf7 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h
@@ -4,6 +4,9 @@
#include <linux/refcount.h>
+/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
+#define MAX_PID_NS_LEVEL 32
+
struct proc_ns_operations;
struct ns_common {
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
index 07481bb87d4e..f814068012d0 100644
--- a/include/linux/pid_namespace.h
+++ b/include/linux/pid_namespace.h
@@ -11,9 +11,6 @@
#include <linux/ns_common.h>
#include <linux/idr.h>
-/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
-#define MAX_PID_NS_LEVEL 32
-
struct fs_pin;
struct pid_namespace {
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 5481ba44a8d6..6ea6e263403d 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -87,7 +87,7 @@ int create_user_ns(struct cred *new)
int ret, i;
ret = -ENOSPC;
- if (parent_ns->level > 32)
+ if (parent_ns->level > MAX_PID_NS_LEVEL)
goto fail;
ucounts = inc_user_namespaces(parent_ns, owner);
--
2.35.1
^ permalink raw reply related [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it
2022-03-25 11:21 [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it Petr Vorel
@ 2022-03-25 13:29 ` Eric W. Biederman
2022-03-25 16:04 ` Petr Vorel
2022-03-25 15:37 ` Christian Brauner
1 sibling, 1 reply; 5+ messages in thread
From: Eric W. Biederman @ 2022-03-25 13:29 UTC (permalink / raw)
To: Petr Vorel
Cc: linux-kernel, Christian Brauner, Alexey Gladkov,
Serge E . Hallyn, Vasily Averin, Andrew Morton
Petr Vorel <pvorel@suse.cz> writes:
> Move MAX_PID_NS_LEVEL to ns_common.h and reuse it in check in
> user_namespace.c.
What is the motivation for this change?
Is it just that there is a bare number in create_user_ns and that is a
little ugly? Or is there something more motivating this?
Eric
>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> Hi Christian, all,
>
> I don't see putting MAX_PID_NS_LEVEL into ns_common.h as an elegant
> solution but IMHO better than use a hardwired number or redefinition in
> user_namespace.h.
>
> Kind regards,
> Petr
>
> include/linux/ns_common.h | 3 +++
> include/linux/pid_namespace.h | 3 ---
> kernel/user_namespace.c | 2 +-
> 3 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
> index 0f1d024bd958..173fab9dadf7 100644
> --- a/include/linux/ns_common.h
> +++ b/include/linux/ns_common.h
> @@ -4,6 +4,9 @@
>
> #include <linux/refcount.h>
>
> +/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
> +#define MAX_PID_NS_LEVEL 32
> +
> struct proc_ns_operations;
>
> struct ns_common {
> diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
> index 07481bb87d4e..f814068012d0 100644
> --- a/include/linux/pid_namespace.h
> +++ b/include/linux/pid_namespace.h
> @@ -11,9 +11,6 @@
> #include <linux/ns_common.h>
> #include <linux/idr.h>
>
> -/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
> -#define MAX_PID_NS_LEVEL 32
> -
> struct fs_pin;
>
> struct pid_namespace {
> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> index 5481ba44a8d6..6ea6e263403d 100644
> --- a/kernel/user_namespace.c
> +++ b/kernel/user_namespace.c
> @@ -87,7 +87,7 @@ int create_user_ns(struct cred *new)
> int ret, i;
>
> ret = -ENOSPC;
> - if (parent_ns->level > 32)
> + if (parent_ns->level > MAX_PID_NS_LEVEL)
> goto fail;
>
> ucounts = inc_user_namespaces(parent_ns, owner);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it
2022-03-25 11:21 [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it Petr Vorel
2022-03-25 13:29 ` Eric W. Biederman
@ 2022-03-25 15:37 ` Christian Brauner
2022-03-25 16:12 ` Petr Vorel
1 sibling, 1 reply; 5+ messages in thread
From: Christian Brauner @ 2022-03-25 15:37 UTC (permalink / raw)
To: Petr Vorel
Cc: linux-kernel, Christian Brauner, Alexey Gladkov,
Eric W . Biederman, Serge E . Hallyn, Vasily Averin,
Andrew Morton
On Fri, Mar 25, 2022 at 12:21:27PM +0100, Petr Vorel wrote:
> Move MAX_PID_NS_LEVEL to ns_common.h and reuse it in check in
> user_namespace.c.
>
> Signed-off-by: Petr Vorel <pvorel@suse.cz>
> ---
> Hi Christian, all,
>
> I don't see putting MAX_PID_NS_LEVEL into ns_common.h as an elegant
> solution but IMHO better than use a hardwired number or redefinition in
> user_namespace.h.
Hey Petr,
Weird I either deleted that message by accident or didn't get it.
>
> Kind regards,
> Petr
>
> include/linux/ns_common.h | 3 +++
> include/linux/pid_namespace.h | 3 ---
> kernel/user_namespace.c | 2 +-
> 3 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
> index 0f1d024bd958..173fab9dadf7 100644
> --- a/include/linux/ns_common.h
> +++ b/include/linux/ns_common.h
> @@ -4,6 +4,9 @@
>
> #include <linux/refcount.h>
>
> +/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
> +#define MAX_PID_NS_LEVEL 32
The only two namespaces where this applies to have the same hard-coded
limit. If you want to get rid of the raw number you should just
introduce a generic define that expresses the limit for both pidns
and userns. Using "MAX_PID_NS_LEVEL" in the userns case is very
confusing. So if you wanted to do this introducing something like
#define MAX_NS_LEVEL 32
and using it in both places makes more sense.
Christian
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it
2022-03-25 13:29 ` Eric W. Biederman
@ 2022-03-25 16:04 ` Petr Vorel
0 siblings, 0 replies; 5+ messages in thread
From: Petr Vorel @ 2022-03-25 16:04 UTC (permalink / raw)
To: Eric W. Biederman
Cc: linux-kernel, Christian Brauner, Alexey Gladkov,
Serge E . Hallyn, Vasily Averin, Andrew Morton
> Petr Vorel <pvorel@suse.cz> writes:
> > Move MAX_PID_NS_LEVEL to ns_common.h and reuse it in check in
> > user_namespace.c.
> What is the motivation for this change?
> Is it just that there is a bare number in create_user_ns and that is a
> little ugly? Or is there something more motivating this?
Well, nothing more than to have constant which gives some description.
Kind regards,
Petr
> Eric
> > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > ---
> > Hi Christian, all,
> > I don't see putting MAX_PID_NS_LEVEL into ns_common.h as an elegant
> > solution but IMHO better than use a hardwired number or redefinition in
> > user_namespace.h.
> > Kind regards,
> > Petr
> > include/linux/ns_common.h | 3 +++
> > include/linux/pid_namespace.h | 3 ---
> > kernel/user_namespace.c | 2 +-
> > 3 files changed, 4 insertions(+), 4 deletions(-)
> > diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
> > index 0f1d024bd958..173fab9dadf7 100644
> > --- a/include/linux/ns_common.h
> > +++ b/include/linux/ns_common.h
> > @@ -4,6 +4,9 @@
> > #include <linux/refcount.h>
> > +/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
> > +#define MAX_PID_NS_LEVEL 32
> > +
> > struct proc_ns_operations;
> > struct ns_common {
> > diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
> > index 07481bb87d4e..f814068012d0 100644
> > --- a/include/linux/pid_namespace.h
> > +++ b/include/linux/pid_namespace.h
> > @@ -11,9 +11,6 @@
> > #include <linux/ns_common.h>
> > #include <linux/idr.h>
> > -/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
> > -#define MAX_PID_NS_LEVEL 32
> > -
> > struct fs_pin;
> > struct pid_namespace {
> > diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> > index 5481ba44a8d6..6ea6e263403d 100644
> > --- a/kernel/user_namespace.c
> > +++ b/kernel/user_namespace.c
> > @@ -87,7 +87,7 @@ int create_user_ns(struct cred *new)
> > int ret, i;
> > ret = -ENOSPC;
> > - if (parent_ns->level > 32)
> > + if (parent_ns->level > MAX_PID_NS_LEVEL)
> > goto fail;
> > ucounts = inc_user_namespaces(parent_ns, owner);
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it
2022-03-25 15:37 ` Christian Brauner
@ 2022-03-25 16:12 ` Petr Vorel
0 siblings, 0 replies; 5+ messages in thread
From: Petr Vorel @ 2022-03-25 16:12 UTC (permalink / raw)
To: Christian Brauner
Cc: linux-kernel, Christian Brauner, Alexey Gladkov,
Eric W . Biederman, Serge E . Hallyn, Vasily Averin,
Andrew Morton
Hi all,
> On Fri, Mar 25, 2022 at 12:21:27PM +0100, Petr Vorel wrote:
> > Move MAX_PID_NS_LEVEL to ns_common.h and reuse it in check in
> > user_namespace.c.
> > Signed-off-by: Petr Vorel <pvorel@suse.cz>
> > ---
> > Hi Christian, all,
> > I don't see putting MAX_PID_NS_LEVEL into ns_common.h as an elegant
> > solution but IMHO better than use a hardwired number or redefinition in
> > user_namespace.h.
> Hey Petr,
> Weird I either deleted that message by accident or didn't get it.
Interesting. BTW I didn't get any bounce suggesting mail to you didn't arrive.
> > Kind regards,
> > Petr
> > include/linux/ns_common.h | 3 +++
> > include/linux/pid_namespace.h | 3 ---
> > kernel/user_namespace.c | 2 +-
> > 3 files changed, 4 insertions(+), 4 deletions(-)
> > diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
> > index 0f1d024bd958..173fab9dadf7 100644
> > --- a/include/linux/ns_common.h
> > +++ b/include/linux/ns_common.h
> > @@ -4,6 +4,9 @@
> > #include <linux/refcount.h>
> > +/* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */
> > +#define MAX_PID_NS_LEVEL 32
> The only two namespaces where this applies to have the same hard-coded
> limit. If you want to get rid of the raw number you should just
> introduce a generic define that expresses the limit for both pidns
> and userns. Using "MAX_PID_NS_LEVEL" in the userns case is very
> confusing. So if you wanted to do this introducing something like
> #define MAX_NS_LEVEL 32
> and using it in both places makes more sense.
Thanks a lot, I overlooked they aren't related.
I wonder if there should be just one constant for both (i.e. MAX_NS_LEVEL) as
you suggest, 2 constants, i.e keep MAX_PID_NS_LEVEL and add MAX_USER_NS_LEVEL
(which happen to be both 32).
Also understand if you prefer just to keep the raw number (MAX_PID_NS_LEVEL has
more use than just a single place, but user namespaces need it just on single
place).
Kind regards,
Petr
> Christian
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-03-25 11:21 [PATCH 1/1] ns: Move MAX_PID_NS_LEVEL to ns_common.h, reuse it Petr Vorel
2022-03-25 13:29 ` Eric W. Biederman
2022-03-25 16:04 ` Petr Vorel
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