[PATCH v20 08/23] LSM: Use lsmblob in security_ipc_getsecid

[Casey Schaufler]

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. The
audit data structure containing the secid will be updated
later, so there is a bit of scaffolding here.

Reviewed-by: Kees Cook <keesc...@chromium.org>
Reviewed-by: John Johansen <john.johan...@canonical.com>
Acked-by: Stephen Smalley <s...@tycho.nsa.gov>
Signed-off-by: Casey Schaufler <ca...@schaufler-ca.com>
---
 include/linux/security.h |  7 ++++---
 kernel/auditsc.c         |  7 ++++++-
 security/security.c      | 12 +++++++++---
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index 5c66348d9ab0..5f38bde9162f 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -494,7 +494,7 @@ int security_task_prctl(int option, unsigned long arg2, 
unsigned long arg3,
                        unsigned long arg4, unsigned long arg5);
 void security_task_to_inode(struct task_struct *p, struct inode *inode);
 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_getsecid(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);
@@ -1215,9 +1215,10 @@ 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_getsecid(struct kern_ipc_perm *ipcp,
+                                        struct lsmblob *blob)
 {
-       *secid = 0;
+       lsmblob_init(blob, 0);
 }
 
 static inline int security_msg_msg_alloc(struct msg_msg *msg)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 5f9bdd62f78d..35d6bd0526a2 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -2341,11 +2341,16 @@ void __audit_mq_getsetattr(mqd_t mqdes, struct mq_attr 
*mqstat)
 void __audit_ipc_obj(struct kern_ipc_perm *ipcp)
 {
        struct audit_context *context = audit_context();
+       struct lsmblob blob;
        context->ipc.uid = ipcp->uid;
        context->ipc.gid = ipcp->gid;
        context->ipc.mode = ipcp->mode;
        context->ipc.has_perm = 0;
-       security_ipc_getsecid(ipcp, &context->ipc.osid);
+       security_ipc_getsecid(ipcp, &blob);
+       /* context->ipc.osid will be changed to a lsmblob later in
+        * the patch series. This will allow auditing of all the object
+        * labels associated with the ipc object. */
+       context->ipc.osid = lsmblob_value(&blob);
        context->type = AUDIT_IPC;
 }
 
diff --git a/security/security.c b/security/security.c
index ce0934395c53..c74c7722e5f4 100644
--- a/security/security.c
+++ b/security/security.c
@@ -1866,10 +1866,16 @@ int security_ipc_permission(struct kern_ipc_perm *ipcp, 
short flag)
        return call_int_hook(ipc_permission, 0, ipcp, flag);
 }
 
-void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid)
+void security_ipc_getsecid(struct kern_ipc_perm *ipcp, struct lsmblob *blob)
 {
-       *secid = 0;
-       call_void_hook(ipc_getsecid, ipcp, secid);
+       struct security_hook_list *hp;
+
+       lsmblob_init(blob, 0);
+       hlist_for_each_entry(hp, &security_hook_heads.ipc_getsecid, list) {
+               if (WARN_ON(hp->lsmid->slot < 0 || hp->lsmid->slot >= lsm_slot))
+                       continue;
+               hp->hook.ipc_getsecid(ipcp, &blob->secid[hp->lsmid->slot]);
+       }
 }
 
 int security_msg_msg_alloc(struct msg_msg *msg)
-- 
2.24.1

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