2017-04-12 09:12:45

by Sebastien Buisson

[permalink] [raw]
Subject: [PATCH] selinux: add selinux_status_get_seq() function

Add selinux_status_get_seq() function to give access to sequence
number of current SELinux policy loaded to the rest of the kernel.

Signed-off-by: Sebastien Buisson <[email protected]>
---
include/linux/selinux.h | 7 +++++++
security/selinux/ss/status.c | 21 +++++++++++++++++++++
2 files changed, 28 insertions(+)

diff --git a/include/linux/selinux.h b/include/linux/selinux.h
index 44f4596..926f9f0 100644
--- a/include/linux/selinux.h
+++ b/include/linux/selinux.h
@@ -24,12 +24,19 @@
* selinux_is_enabled - is SELinux enabled?
*/
bool selinux_is_enabled(void);
+u32 selinux_status_get_seq(void);
#else

static inline bool selinux_is_enabled(void)
{
return false;
}
+
+static inline u32 selinux_status_get_seq(void)
+{
+ return 0;
+}
+
#endif /* CONFIG_SECURITY_SELINUX */

#endif /* _LINUX_SELINUX_H */
diff --git a/security/selinux/ss/status.c b/security/selinux/ss/status.c
index d982365..a0670d3 100644
--- a/security/selinux/ss/status.c
+++ b/security/selinux/ss/status.c
@@ -124,3 +124,24 @@ void selinux_status_update_policyload(int seqno)
}
mutex_unlock(&selinux_status_lock);
}
+
+/*
+ * selinux_status_get_seq
+ *
+ * It gets current sequence of policy loaded.
+ */
+u32 selinux_status_get_seq(void)
+{
+ struct selinux_kernel_status *status;
+ u32 seq = 0;
+
+ mutex_lock(&selinux_status_lock);
+ if (selinux_status_page) {
+ status = page_address(selinux_status_page);
+ seq = status->sequence;
+ }
+ mutex_unlock(&selinux_status_lock);
+
+ return seq;
+}
+EXPORT_SYMBOL_GPL(selinux_status_get_seq);
--
1.8.3.1


2017-04-12 11:55:44

by Paul Moore

[permalink] [raw]
Subject: Re: [PATCH] selinux: add selinux_status_get_seq() function

On Wed, Apr 12, 2017 at 5:12 AM, Sebastien Buisson
<[email protected]> wrote:
> Add selinux_status_get_seq() function to give access to sequence
> number of current SELinux policy loaded to the rest of the kernel.
>
> Signed-off-by: Sebastien Buisson <[email protected]>
> ---
> include/linux/selinux.h | 7 +++++++
> security/selinux/ss/status.c | 21 +++++++++++++++++++++
> 2 files changed, 28 insertions(+)

See my comments on your other patch, they apply here as well.

> diff --git a/include/linux/selinux.h b/include/linux/selinux.h
> index 44f4596..926f9f0 100644
> --- a/include/linux/selinux.h
> +++ b/include/linux/selinux.h
> @@ -24,12 +24,19 @@
> * selinux_is_enabled - is SELinux enabled?
> */
> bool selinux_is_enabled(void);
> +u32 selinux_status_get_seq(void);
> #else
>
> static inline bool selinux_is_enabled(void)
> {
> return false;
> }
> +
> +static inline u32 selinux_status_get_seq(void)
> +{
> + return 0;
> +}
> +
> #endif /* CONFIG_SECURITY_SELINUX */
>
> #endif /* _LINUX_SELINUX_H */
> diff --git a/security/selinux/ss/status.c b/security/selinux/ss/status.c
> index d982365..a0670d3 100644
> --- a/security/selinux/ss/status.c
> +++ b/security/selinux/ss/status.c
> @@ -124,3 +124,24 @@ void selinux_status_update_policyload(int seqno)
> }
> mutex_unlock(&selinux_status_lock);
> }
> +
> +/*
> + * selinux_status_get_seq
> + *
> + * It gets current sequence of policy loaded.
> + */
> +u32 selinux_status_get_seq(void)
> +{
> + struct selinux_kernel_status *status;
> + u32 seq = 0;
> +
> + mutex_lock(&selinux_status_lock);
> + if (selinux_status_page) {
> + status = page_address(selinux_status_page);
> + seq = status->sequence;
> + }
> + mutex_unlock(&selinux_status_lock);
> +
> + return seq;
> +}
> +EXPORT_SYMBOL_GPL(selinux_status_get_seq);
> --
> 1.8.3.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html



--
paul moore
security @ redhat

2017-04-12 12:28:06

by Stephen Smalley

[permalink] [raw]
Subject: Re: [PATCH] selinux: add selinux_status_get_seq() function

On Wed, 2017-04-12 at 18:12 +0900, Sebastien Buisson wrote:
> Add selinux_status_get_seq() function to give access to sequence
> number of current SELinux policy loaded to the rest of the kernel.
>
> Signed-off-by: Sebastien Buisson <[email protected]>
> ---
>  include/linux/selinux.h      |  7 +++++++
>  security/selinux/ss/status.c | 21 +++++++++++++++++++++
>  2 files changed, 28 insertions(+)
>
> diff --git a/include/linux/selinux.h b/include/linux/selinux.h
> index 44f4596..926f9f0 100644
> --- a/include/linux/selinux.h
> +++ b/include/linux/selinux.h
> @@ -24,12 +24,19 @@
>   * selinux_is_enabled - is SELinux enabled?
>   */
>  bool selinux_is_enabled(void);
> +u32 selinux_status_get_seq(void);
>  #else
>  
>  static inline bool selinux_is_enabled(void)
>  {
>   return false;
>  }
> +
> +static inline u32 selinux_status_get_seq(void)
> +{
> + return 0;
> +}
> +
>  #endif /* CONFIG_SECURITY_SELINUX */
>  
>  #endif /* _LINUX_SELINUX_H */
> diff --git a/security/selinux/ss/status.c
> b/security/selinux/ss/status.c
> index d982365..a0670d3 100644
> --- a/security/selinux/ss/status.c
> +++ b/security/selinux/ss/status.c
> @@ -124,3 +124,24 @@ void selinux_status_update_policyload(int seqno)
>   }
>   mutex_unlock(&selinux_status_lock);
>  }
> +
> +/*
> + * selinux_status_get_seq
> + *
> + * It gets current sequence of policy loaded.
> + */
> +u32 selinux_status_get_seq(void)
> +{
> + struct selinux_kernel_status   *status;
> + u32 seq = 0;
> +
> + mutex_lock(&selinux_status_lock);
> + if (selinux_status_page) {
> + status = page_address(selinux_status_page);
> + seq = status->sequence;
> + }
> + mutex_unlock(&selinux_status_lock);
> +
> + return seq;
> +}
> +EXPORT_SYMBOL_GPL(selinux_status_get_seq);

status->sequence is a sequence number for the seqlock logic, not the
policy sequence number. You likely want avc_policy_seqno() instead,
although I can't tell without seeing the user of this function.
Regardless, as with the other patch, there needs to be an in-tree user
and a LSM hook interface to use this outside of the SELinux code
itself.