[PATCH 05/13] LSM: Use lsmblob in security_ipc_getsecid
Stephen Smalley
stephen.smalley.work at gmail.com
Tue Aug 27 12:23:56 UTC 2024
On Sun, Aug 25, 2024 at 3:02 PM Casey Schaufler <casey at 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.
>
> Reviewed-by: Kees Cook <keescook at chromium.org>
> Reviewed-by: John Johansen <john.johansen at canonical.com>
> Acked-by: Stephen Smalley <stephen.smalley.work at gmail.com>
> Acked-by: Paul Moore <paul at paul-moore.com>
> Signed-off-by: Casey Schaufler <casey at schaufler-ca.com>
> Cc: linux-audit at redhat.com
> Cc: audit at vger.kernel.org
1. Need to cc selinux list on patches that modify it.
2. Can't retain Acked-by or Reviewed-by lines if the patch has changed
since the review.
> ---
> 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
>
> int call_blocking_lsm_notifier(enum lsm_event event, void *data);
> @@ -500,7 +511,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3,
> void security_task_to_inode(struct task_struct *p, struct inode *inode);
> int security_create_user_ns(const struct cred *cred);
> int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag);
> -void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid);
> +void security_ipc_getlsmblob(struct kern_ipc_perm *ipcp, struct lsmblob *blob);
> int security_msg_msg_alloc(struct msg_msg *msg);
> void security_msg_msg_free(struct msg_msg *msg);
> int security_msg_queue_alloc(struct kern_ipc_perm *msq);
> @@ -1340,9 +1351,10 @@ static inline int security_ipc_permission(struct kern_ipc_perm *ipcp,
> return 0;
> }
>
> -static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
> +static inline void security_ipc_getlsmblob(struct kern_ipc_perm *ipcp,
> + struct lsmblob *blob)
> {
> - *secid = 0;
> + lsmblob_init(blob);
> }
>
> static inline int security_msg_msg_alloc(struct msg_msg *msg)
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 84f6e9356b8f..94b7ef89da2e 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -2638,8 +2638,7 @@ void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
> context->ipc.gid = ipcp->gid;
> context->ipc.mode = ipcp->mode;
> context->ipc.has_perm = 0;
> - /* scaffolding */
> - security_ipc_getsecid(ipcp, &context->ipc.oblob.scaffold.secid);
> + security_ipc_getlsmblob(ipcp, &context->ipc.oblob);
> context->type = AUDIT_IPC;
> }
>
> diff --git a/security/security.c b/security/security.c
> index bb541a3be410..6e72e678b5b4 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -3611,17 +3611,17 @@ int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
> }
>
> /**
> - * security_ipc_getsecid() - Get the sysv ipc object's secid
> + * security_ipc_getlsmblob() - Get the sysv ipc object LSM data
> * @ipcp: ipc permission structure
> - * @secid: secid pointer
> + * @blob: pointer to lsm information
> *
> - * Get the secid associated with the ipc object. In case of failure, @secid
> - * will be set to zero.
> + * Get the lsm information associated with the ipc object.
> */
> -void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
> +
> +void security_ipc_getlsmblob(struct kern_ipc_perm *ipcp, struct lsmblob *blob)
> {
> - *secid = 0;
> - call_void_hook(ipc_getsecid, ipcp, secid);
> + lsmblob_init(blob);
> + call_void_hook(ipc_getlsmblob, ipcp, blob);
> }
>
> /**
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 102489e6d579..1b34b86426e8 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -6328,10 +6328,13 @@ static int selinux_ipc_permission(struct kern_ipc_perm *ipcp, short flag)
> return ipc_has_perm(ipcp, av);
> }
>
> -static void selinux_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
> +static void selinux_ipc_getlsmblob(struct kern_ipc_perm *ipcp,
> + struct lsmblob *blob)
> {
> struct ipc_security_struct *isec = selinux_ipc(ipcp);
> - *secid = isec->sid;
> + blob->selinux.secid = isec->sid;
> + /* scaffolding */
> + blob->scaffold.secid = isec->sid;
> }
>
> static void selinux_d_instantiate(struct dentry *dentry, struct inode *inode)
> @@ -7252,7 +7255,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
> LSM_HOOK_INIT(userns_create, selinux_userns_create),
>
> LSM_HOOK_INIT(ipc_permission, selinux_ipc_permission),
> - LSM_HOOK_INIT(ipc_getsecid, selinux_ipc_getsecid),
> + LSM_HOOK_INIT(ipc_getlsmblob, selinux_ipc_getlsmblob),
>
> LSM_HOOK_INIT(msg_queue_associate, selinux_msg_queue_associate),
> LSM_HOOK_INIT(msg_queue_msgctl, selinux_msg_queue_msgctl),
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 5d74d8590862..370ca7fb1843 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -3442,16 +3442,19 @@ static int smack_ipc_permission(struct kern_ipc_perm *ipp, short flag)
> }
>
> /**
> - * smack_ipc_getsecid - Extract smack security id
> + * smack_ipc_getlsmblob - Extract smack security data
> * @ipp: the object permissions
> - * @secid: where result will be saved
> + * @blob: where result will be saved
> */
> -static void smack_ipc_getsecid(struct kern_ipc_perm *ipp, u32 *secid)
> +static void smack_ipc_getlsmblob(struct kern_ipc_perm *ipp,
> + struct lsmblob *blob)
> {
> - struct smack_known **blob = smack_ipc(ipp);
> - struct smack_known *iskp = *blob;
> + struct smack_known **iskpp = smack_ipc(ipp);
> + struct smack_known *iskp = *iskpp;
>
> - *secid = iskp->smk_secid;
> + blob->smack.skp = iskp;
> + /* scaffolding */
> + blob->scaffold.secid = iskp->smk_secid;
> }
>
> /**
> @@ -5157,7 +5160,7 @@ static struct security_hook_list smack_hooks[] __ro_after_init = {
> LSM_HOOK_INIT(task_to_inode, smack_task_to_inode),
>
> LSM_HOOK_INIT(ipc_permission, smack_ipc_permission),
> - LSM_HOOK_INIT(ipc_getsecid, smack_ipc_getsecid),
> + LSM_HOOK_INIT(ipc_getlsmblob, smack_ipc_getlsmblob),
>
> LSM_HOOK_INIT(msg_msg_alloc_security, smack_msg_msg_alloc_security),
>
> --
> 2.41.0
>
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