2022-08-18 15:53:31

by Roberto Sassu

Subject: [PATCH v12 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h

From: Roberto Sassu <[email protected]>

In preparation for the patch that introduces the bpf_lookup_user_key() eBPF
kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to
validate the kfunc parameters.

Also, introduce key_lookup_flags_check() directly in include/linux/key.h,
to reduce the risk that the check is not in sync with currently defined
flags.

Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: KP Singh <[email protected]>
---
include/linux/key.h | 11 +++++++++++
security/keys/internal.h | 2 --
2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/include/linux/key.h b/include/linux/key.h
index 7febc4881363..b5bbae77a9e7 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -88,6 +88,17 @@ enum key_need_perm {
KEY_DEFER_PERM_CHECK, /* Special: permission check is deferred */
};

+#define KEY_LOOKUP_CREATE 0x01
+#define KEY_LOOKUP_PARTIAL 0x02
+
+static inline int key_lookup_flags_check(u64 flags)
+{
+ if (flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))
+ return -EINVAL;
+
+ return 0;
+}
+
struct seq_file;
struct user_struct;
struct signal_struct;
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 9b9cf3b6fcbb..3c1e7122076b 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -165,8 +165,6 @@ extern struct key *request_key_and_link(struct key_type *type,

extern bool lookup_user_key_possessed(const struct key *key,
const struct key_match_data *match_data);
-#define KEY_LOOKUP_CREATE 0x01
-#define KEY_LOOKUP_PARTIAL 0x02

extern long join_session_keyring(const char *name);
extern void key_change_session_keyring(struct callback_head *twork);
--
2.25.1

2022-08-26 05:57:15

by Jarkko Sakkinen

Subject: Re: [PATCH v12 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h

On Thu, Aug 18, 2022 at 05:29:23PM +0200, [email protected] wrote:
> From: Roberto Sassu <[email protected]>
>
> In preparation for the patch that introduces the bpf_lookup_user_key() eBPF
> kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to
> validate the kfunc parameters.
>
> Also, introduce key_lookup_flags_check() directly in include/linux/key.h,
> to reduce the risk that the check is not in sync with currently defined
> flags.

Missing the description what the heck this function even is.

Please, explain that.

Also, the short subject is misleading because this *just*
does not move flags.

>
> Signed-off-by: Roberto Sassu <[email protected]>
> Reviewed-by: KP Singh <[email protected]>
> ---
> include/linux/key.h | 11 +++++++++++
> security/keys/internal.h | 2 --
> 2 files changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/key.h b/include/linux/key.h
> index 7febc4881363..b5bbae77a9e7 100644
> --- a/include/linux/key.h
> +++ b/include/linux/key.h
> @@ -88,6 +88,17 @@ enum key_need_perm {
> KEY_DEFER_PERM_CHECK, /* Special: permission check is deferred */
> };
>
> +#define KEY_LOOKUP_CREATE 0x01
> +#define KEY_LOOKUP_PARTIAL 0x02
> +

/*
* Explain what the heck this function is.
*/
> +static inline int key_lookup_flags_check(u64 flags)
> +{
> + if (flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))
> + return -EINVAL;
> +
> + return 0;
> +}

This is essentially a boolean function, right?

I.e. the implementation can be just:

!!(flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))

Not even sure if this is needed in the first place, or
would it be better just to open code it. How many call
sites does it have anyway?

BR, Jarkko

2022-08-26 07:31:18

by Roberto Sassu

Subject: Re: [PATCH v12 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h

On Fri, 2022-08-26 at 08:42 +0300, Jarkko Sakkinen wrote:
> On Thu, Aug 18, 2022 at 05:29:23PM +0200,
> [email protected] wrote:
> > From: Roberto Sassu <[email protected]>
> >
> > In preparation for the patch that introduces the
> > bpf_lookup_user_key() eBPF
> > kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be
> > able to
> > validate the kfunc parameters.
> >
> > Also, introduce key_lookup_flags_check() directly in
> > include/linux/key.h,
> > to reduce the risk that the check is not in sync with currently
> > defined
> > flags.
>
> Missing the description what the heck this function even is.
>
> Please, explain that.

Hi Jarkko

sorry, forgot to update the commit description. Will do it.

> Also, the short subject is misleading because this *just*
> does not move flags.
>
> > Signed-off-by: Roberto Sassu <[email protected]>
> > Reviewed-by: KP Singh <[email protected]>
> > ---
> > include/linux/key.h | 11 +++++++++++
> > security/keys/internal.h | 2 --
> > 2 files changed, 11 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/key.h b/include/linux/key.h
> > index 7febc4881363..b5bbae77a9e7 100644
> > --- a/include/linux/key.h
> > +++ b/include/linux/key.h
> > @@ -88,6 +88,17 @@ enum key_need_perm {
> > KEY_DEFER_PERM_CHECK, /* Special: permission check is
> > deferred */
> > };
> >
> > +#define KEY_LOOKUP_CREATE 0x01
> > +#define KEY_LOOKUP_PARTIAL 0x02
> > +
>
> /*
> * Explain what the heck this function is.
> */
> > +static inline int key_lookup_flags_check(u64 flags)
> > +{
> > + if (flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
>
> This is essentially a boolean function, right?
>
> I.e. the implementation can be just:
>
> !!(flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))

Absolutely fine with that, if you prefer.

> Not even sure if this is needed in the first place, or
> would it be better just to open code it. How many call
> sites does it have anyway?
>

Daniel preferred to have this check here.

Thanks

Roberto

2022-08-26 10:01:57

by Roberto Sassu

Subject: [PATCH v14 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h and add flags check function

From: Roberto Sassu <[email protected]>

In preparation for the patch that introduces the bpf_lookup_user_key() eBPF
kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be able to
validate the kfunc parameters.

Also, introduce key_lookup_flags_valid() to check if the caller set in the
argument only defined flags. Introduce it directly in include/linux/key.h,
to reduce the risk that the check is not in sync with currently defined
flags.

Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: KP Singh <[email protected]>
---
include/linux/key.h | 16 ++++++++++++++++
security/keys/internal.h | 2 --
2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/include/linux/key.h b/include/linux/key.h
index 7febc4881363..e679dbf0c940 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -88,6 +88,22 @@ enum key_need_perm {
KEY_DEFER_PERM_CHECK, /* Special: permission check is deferred */
};

+#define KEY_LOOKUP_CREATE 0x01
+#define KEY_LOOKUP_PARTIAL 0x02
+
+/**
+ * key_lookup_flags_valid - detect if provided key lookup flags are valid
+ * @flags: key lookup flags.
+ *
+ * Verify whether or not the caller set in the argument only defined flags.
+ *
+ * Return: true if flags are valid, false if not.
+ */
+static inline bool key_lookup_flags_valid(u64 flags)
+{
+ return !(flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL));
+}
+
struct seq_file;
struct user_struct;
struct signal_struct;
diff --git a/security/keys/internal.h b/security/keys/internal.h
index 9b9cf3b6fcbb..3c1e7122076b 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -165,8 +165,6 @@ extern struct key *request_key_and_link(struct key_type *type,

extern bool lookup_user_key_possessed(const struct key *key,
const struct key_match_data *match_data);
-#define KEY_LOOKUP_CREATE 0x01
-#define KEY_LOOKUP_PARTIAL 0x02

extern long join_session_keyring(const char *name);
extern void key_change_session_keyring(struct callback_head *twork);
--
2.25.1

2022-08-28 05:26:49

by Jarkko Sakkinen

Subject: Re: [PATCH v12 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h

On Fri, Aug 26, 2022 at 09:14:09AM +0200, Roberto Sassu wrote:
> On Fri, 2022-08-26 at 08:42 +0300, Jarkko Sakkinen wrote:
> > On Thu, Aug 18, 2022 at 05:29:23PM +0200,
> > [email protected] wrote:
> > > From: Roberto Sassu <[email protected]>
> > >
> > > In preparation for the patch that introduces the
> > > bpf_lookup_user_key() eBPF
> > > kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be
> > > able to
> > > validate the kfunc parameters.
> > >
> > > Also, introduce key_lookup_flags_check() directly in
> > > include/linux/key.h,
> > > to reduce the risk that the check is not in sync with currently
> > > defined
> > > flags.
> >
> > Missing the description what the heck this function even is.
> >
> > Please, explain that.
>
> Hi Jarkko
>
> sorry, forgot to update the commit description. Will do it.
>
> > Also, the short subject is misleading because this *just*
> > does not move flags.
> >
> > > Signed-off-by: Roberto Sassu <[email protected]>
> > > Reviewed-by: KP Singh <[email protected]>
> > > ---
> > > include/linux/key.h | 11 +++++++++++
> > > security/keys/internal.h | 2 --
> > > 2 files changed, 11 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/include/linux/key.h b/include/linux/key.h
> > > index 7febc4881363..b5bbae77a9e7 100644
> > > --- a/include/linux/key.h
> > > +++ b/include/linux/key.h
> > > @@ -88,6 +88,17 @@ enum key_need_perm {
> > > KEY_DEFER_PERM_CHECK, /* Special: permission check is
> > > deferred */
> > > };
> > >
> > > +#define KEY_LOOKUP_CREATE 0x01
> > > +#define KEY_LOOKUP_PARTIAL 0x02
> > > +
> >
> > /*
> > * Explain what the heck this function is.
> > */
> > > +static inline int key_lookup_flags_check(u64 flags)
> > > +{
> > > + if (flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))
> > > + return -EINVAL;
> > > +
> > > + return 0;
> > > +}
> >
> > This is essentially a boolean function, right?
> >
> > I.e. the implementation can be just:
> >
> > !!(flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))
>
> Absolutely fine with that, if you prefer.

It can be either, it more depends on if a new function
is needed in the first place.

E.g. if you are worried about maintaining you could just
as well define a constant containing the mask, right?

>
> > Not even sure if this is needed in the first place, or
> > would it be better just to open code it. How many call
> > sites does it have anyway?
> >
>
> Daniel preferred to have this check here.

How many call sites?

BR, Jarkko

2022-08-28 12:48:27

by KP Singh

Subject: Re: [PATCH v12 04/10] KEYS: Move KEY_LOOKUP_ to include/linux/key.h

On Sun, Aug 28, 2022 at 5:57 AM Jarkko Sakkinen <[email protected]> wrote:
>
> On Fri, Aug 26, 2022 at 09:14:09AM +0200, Roberto Sassu wrote:
> > On Fri, 2022-08-26 at 08:42 +0300, Jarkko Sakkinen wrote:
> > > On Thu, Aug 18, 2022 at 05:29:23PM +0200,
> > > [email protected] wrote:
> > > > From: Roberto Sassu <[email protected]>
> > > >
> > > > In preparation for the patch that introduces the
> > > > bpf_lookup_user_key() eBPF
> > > > kfunc, move KEY_LOOKUP_ definitions to include/linux/key.h, to be
> > > > able to
> > > > validate the kfunc parameters.
> > > >
> > > > Also, introduce key_lookup_flags_check() directly in
> > > > include/linux/key.h,
> > > > to reduce the risk that the check is not in sync with currently
> > > > defined
> > > > flags.
> > >
> > > Missing the description what the heck this function even is.
> > >
> > > Please, explain that.
> >
> > Hi Jarkko
> >
> > sorry, forgot to update the commit description. Will do it.
> >
> > > Also, the short subject is misleading because this *just*
> > > does not move flags.
> > >
> > > > Signed-off-by: Roberto Sassu <[email protected]>
> > > > Reviewed-by: KP Singh <[email protected]>
> > > > ---
> > > > include/linux/key.h | 11 +++++++++++
> > > > security/keys/internal.h | 2 --
> > > > 2 files changed, 11 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/include/linux/key.h b/include/linux/key.h
> > > > index 7febc4881363..b5bbae77a9e7 100644
> > > > --- a/include/linux/key.h
> > > > +++ b/include/linux/key.h
> > > > @@ -88,6 +88,17 @@ enum key_need_perm {
> > > > KEY_DEFER_PERM_CHECK, /* Special: permission check is
> > > > deferred */
> > > > };
> > > >
> > > > +#define KEY_LOOKUP_CREATE 0x01
> > > > +#define KEY_LOOKUP_PARTIAL 0x02
> > > > +
> > >
> > > /*
> > > * Explain what the heck this function is.
> > > */
> > > > +static inline int key_lookup_flags_check(u64 flags)
> > > > +{
> > > > + if (flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))
> > > > + return -EINVAL;
> > > > +
> > > > + return 0;
> > > > +}
> > >
> > > This is essentially a boolean function, right?
> > >
> > > I.e. the implementation can be just:
> > >
> > > !!(flags & ~(KEY_LOOKUP_CREATE | KEY_LOOKUP_PARTIAL))
> >
> > Absolutely fine with that, if you prefer.
>
> It can be either, it more depends on if a new function
> is needed in the first place.
>
> E.g. if you are worried about maintaining you could just
> as well define a constant containing the mask, right?

+1 A mask is better.

>
> >
> > > Not even sure if this is needed in the first place, or
> > > would it be better just to open code it. How many call
> > > sites does it have anyway?
> > >
> >
> > Daniel preferred to have this check here.
>
> How many call sites?
>
> BR, Jarkko