CRED: Use RCU to access another task's creds and to release a task's own creds

[mirror_ubuntu-bionic-kernel.git] / kernel / auditsc.c

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 2febf5165fade49ef54981042c9bffd73961b096..ae8ef88ade3f859af04a01f736084856c3b9ce18 100644 (file)
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -447,7 +447,7 @@ static int audit_filter_rules(struct task_struct *tsk,
                              struct audit_names *name,
                              enum audit_state *state)
 {
-       struct cred *cred = tsk->cred;
+       const struct cred *cred = get_task_cred(tsk);
        int i, j, need_sid = 1;
        u32 sid;
 
@@ -642,8 +642,10 @@ static int audit_filter_rules(struct task_struct *tsk,
                        break;
                }
 
-               if (!result)
+               if (!result) {
+                       put_cred(cred);
                        return 0;
+               }
        }
        if (rule->filterkey && ctx)
                ctx->filterkey = kstrdup(rule->filterkey, GFP_ATOMIC);
@@ -651,6 +653,7 @@ static int audit_filter_rules(struct task_struct *tsk,
        case AUDIT_NEVER:    *state = AUDIT_DISABLED;       break;
        case AUDIT_ALWAYS:   *state = AUDIT_RECORD_CONTEXT; break;
        }
+       put_cred(cred);
        return 1;
 }
 
@@ -1229,7 +1232,7 @@ static void audit_log_fcaps(struct audit_buffer *ab, struct audit_names *name)
 
 static void audit_log_exit(struct audit_context *context, struct task_struct *tsk)
 {
-       struct cred *cred = tsk->cred;
+       const struct cred *cred;
        int i, call_panic = 0;
        struct audit_buffer *ab;
        struct audit_aux_data *aux;
@@ -1239,13 +1242,14 @@ static void audit_log_exit(struct audit_context *context, struct task_struct *ts
        context->pid = tsk->pid;
        if (!context->ppid)
                context->ppid = sys_getppid();
-       context->uid = cred->uid;
-       context->gid = cred->gid;
-       context->euid = cred->euid;
-       context->suid = cred->suid;
+       cred = current_cred();
+       context->uid   = cred->uid;
+       context->gid   = cred->gid;
+       context->euid  = cred->euid;
+       context->suid  = cred->suid;
        context->fsuid = cred->fsuid;
-       context->egid = cred->egid;
-       context->sgid = cred->sgid;
+       context->egid  = cred->egid;
+       context->sgid  = cred->sgid;
        context->fsgid = cred->fsgid;
        context->personality = tsk->personality;
 
@@ -2088,7 +2092,7 @@ int audit_set_loginuid(struct task_struct *task, uid_t loginuid)
                        audit_log_format(ab, "login pid=%d uid=%u "
                                "old auid=%u new auid=%u"
                                " old ses=%u new ses=%u",
-                               task->pid, task->cred->uid,
+                               task->pid, task_uid(task),
                                task->loginuid, loginuid,
                                task->sessionid, sessionid);
                        audit_log_end(ab);
@@ -2471,7 +2475,7 @@ void __audit_ptrace(struct task_struct *t)
 
        context->target_pid = t->pid;
        context->target_auid = audit_get_loginuid(t);
-       context->target_uid = t->cred->uid;
+       context->target_uid = task_uid(t);
        context->target_sessionid = audit_get_sessionid(t);
        security_task_getsecid(t, &context->target_sid);
        memcpy(context->target_comm, t->comm, TASK_COMM_LEN);
@@ -2490,6 +2494,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
        struct audit_aux_data_pids *axp;
        struct task_struct *tsk = current;
        struct audit_context *ctx = tsk->audit_context;
+       uid_t uid = current_uid(), t_uid = task_uid(t);
 
        if (audit_pid && t->tgid == audit_pid) {
                if (sig == SIGTERM || sig == SIGHUP || sig == SIGUSR1 || sig == SIGUSR2) {
@@ -2497,7 +2502,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
                        if (tsk->loginuid != -1)
                                audit_sig_uid = tsk->loginuid;
                        else
-                               audit_sig_uid = tsk->cred->uid;
+                               audit_sig_uid = uid;
                        security_task_getsecid(tsk, &audit_sig_sid);
                }
                if (!audit_signals || audit_dummy_context())
@@ -2509,7 +2514,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
        if (!ctx->target_pid) {
                ctx->target_pid = t->tgid;
                ctx->target_auid = audit_get_loginuid(t);
-               ctx->target_uid = t->cred->uid;
+               ctx->target_uid = t_uid;
                ctx->target_sessionid = audit_get_sessionid(t);
                security_task_getsecid(t, &ctx->target_sid);
                memcpy(ctx->target_comm, t->comm, TASK_COMM_LEN);
@@ -2530,7 +2535,7 @@ int __audit_signal_info(int sig, struct task_struct *t)
 
        axp->target_pid[axp->pid_count] = t->tgid;
        axp->target_auid[axp->pid_count] = audit_get_loginuid(t);
-       axp->target_uid[axp->pid_count] = t->cred->uid;
+       axp->target_uid[axp->pid_count] = t_uid;
        axp->target_sessionid[axp->pid_count] = audit_get_sessionid(t);
        security_task_getsecid(t, &axp->target_sid[axp->pid_count]);
        memcpy(axp->target_comm[axp->pid_count], t->comm, TASK_COMM_LEN);