Re: [PATCH v2 5/13] LSM: Use lsmblob in security_ipc_getsecid

[Paul Moore <paul@paul-moore.com>]

On Aug 29, 2024 Casey Schaufler <casey@schaufler-ca.com> wrote:
> 
> There may be more than one LSM that provides IPC data for auditing.
> Change security_ipc_getsecid() to fill in a lsmblob structure instead
> of the u32 secid.  Change the name to security_ipc_getlsmblob() to
> reflect the change.  The audit data structure containing the secid
> will be updated later, so there is a bit of scaffolding here.

I think that last sentence needs to be updated based on the current
ordering in the patchset.

> Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> Cc: audit@vger.kernel.org
> Cc: linux-security-module@vger.kernel.org
> Cc: selinux@vger.kernel.org
> ---
>  include/linux/lsm_hook_defs.h |  4 ++--
>  include/linux/security.h      | 18 +++++++++++++++---
>  kernel/auditsc.c              |  3 +--
>  security/security.c           | 14 +++++++-------
>  security/selinux/hooks.c      |  9 ++++++---
>  security/smack/smack_lsm.c    | 17 ++++++++++-------
>  6 files changed, 41 insertions(+), 24 deletions(-)
> 
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index 3e5f6baa7b9f..c3ffc3f98343 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -253,8 +253,8 @@ LSM_HOOK(void, LSM_RET_VOID, task_to_inode, struct task_struct *p,
>  	 struct inode *inode)
>  LSM_HOOK(int, 0, userns_create, const struct cred *cred)
>  LSM_HOOK(int, 0, ipc_permission, struct kern_ipc_perm *ipcp, short flag)
> -LSM_HOOK(void, LSM_RET_VOID, ipc_getsecid, struct kern_ipc_perm *ipcp,
> -	 u32 *secid)
> +LSM_HOOK(void, LSM_RET_VOID, ipc_getlsmblob, struct kern_ipc_perm *ipcp,
> +	 struct lsmblob *blob)
>  LSM_HOOK(int, 0, msg_msg_alloc_security, struct msg_msg *msg)
>  LSM_HOOK(void, LSM_RET_VOID, msg_msg_free_security, struct msg_msg *msg)
>  LSM_HOOK(int, 0, msg_queue_alloc_security, struct kern_ipc_perm *perm)
> diff --git a/include/linux/security.h b/include/linux/security.h
> index a0b23b6e8734..ebe8edaae953 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -290,6 +290,17 @@ static inline bool lsmblob_is_set(struct lsmblob *blob)
>  	return !!memcmp(blob, &empty, sizeof(*blob));
>  }
>  
> +/**
> + * lsmblob_init - initialize a lsmblob structure
> + * @blob: Pointer to the data to initialize
> + *
> + * Set all secid for all modules to the specified value.
> + */
> +static inline void lsmblob_init(struct lsmblob *blob)
> +{
> +	memset(blob, 0, sizeof(*blob));
> +}
> +
>  #ifdef CONFIG_SECURITY

Once again, I think we may want a !CONFIG_SECURITY variant too.

--
paul-moore.com