MFC r280130:

  cred: add proc_set_cred helper

8 files changed, 55 insertions, 27 deletions

diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index ae6bd3a..03a3d9e 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -437,6 +437,7 @@ proc0_init(void *dummy __unused)
 {
 	struct proc *p;
 	struct thread *td;
+	struct ucred *newcred;
 	vm_paddr_t pageablemem;
 	int i;
 
@@ -513,19 +514,20 @@ proc0_init(void *dummy __unused)
 	callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
 
 	/* Create credentials. */
-	p->p_ucred = crget();
-	p->p_ucred->cr_ngroups = 1;	/* group 0 */
-	p->p_ucred->cr_uidinfo = uifind(0);
-	p->p_ucred->cr_ruidinfo = uifind(0);
-	p->p_ucred->cr_prison = &prison0;
-	p->p_ucred->cr_loginclass = loginclass_find("default");
+	newcred = crget();
+	newcred->cr_ngroups = 1;	/* group 0 */
+	newcred->cr_uidinfo = uifind(0);
+	newcred->cr_ruidinfo = uifind(0);
+	newcred->cr_prison = &prison0;
+	newcred->cr_loginclass = loginclass_find("default");
+	proc_set_cred(p, newcred);
 #ifdef AUDIT
-	audit_cred_kproc0(p->p_ucred);
+	audit_cred_kproc0(newcred);
 #endif
 #ifdef MAC
-	mac_cred_create_swapper(p->p_ucred);
+	mac_cred_create_swapper(newcred);
 #endif
-	td->td_ucred = crhold(p->p_ucred);
+	td->td_ucred = crhold(newcred);
 
 	/* Create sigacts. */
 	p->p_sigacts = sigacts_alloc();
@@ -844,7 +846,7 @@ create_init(const void *udata __unused)
 #ifdef AUDIT
 	audit_cred_proc1(newcred);
 #endif
-	initproc->p_ucred = newcred;
+	proc_set_cred(initproc, newcred);
 	PROC_UNLOCK(initproc);
 	sx_xunlock(&proctree_lock);
 	crfree(oldcred);
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 188eba7..ef51347 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -751,7 +751,7 @@ interpret:
 		 */
 		change_svuid(newcred, newcred->cr_uid);
 		change_svgid(newcred, newcred->cr_gid);
-		p->p_ucred = newcred;
+		proc_set_cred(p, newcred);
 	} else {
 		if (oldcred->cr_uid == oldcred->cr_ruid &&
 		    oldcred->cr_gid == oldcred->cr_rgid)
@@ -777,7 +777,7 @@ interpret:
 			PROC_LOCK(p);
 			change_svuid(newcred, newcred->cr_uid);
 			change_svgid(newcred, newcred->cr_gid);
-			p->p_ucred = newcred;
+			proc_set_cred(p, newcred);
 		}
 	}
 
diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index 76b4427..cb7387d 100644
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -937,7 +937,7 @@ proc_reap(struct thread *td, struct proc *p, int *status, int options)
 	 * Free credentials, arguments, and sigacts.
 	 */
 	crfree(p->p_ucred);
-	p->p_ucred = NULL;
+	proc_set_cred(p, NULL);
 	pargs_drop(p->p_args);
 	p->p_args = NULL;
 	sigacts_free(p->p_sigacts);
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 7b02c4d..6f5f74b 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -413,7 +413,8 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
 	p2->p_treeflag = 0;
 	p2->p_filemon = NULL;
 
-	p2->p_ucred = crhold(td->td_ucred);
+	crhold(td->td_ucred);
+	proc_set_cred(p2, td->td_ucred);
 
 	/* Tell the prison that we exist. */
 	prison_proc_hold(p2->p_ucred->cr_prison);
@@ -913,7 +914,7 @@ fork1(struct thread *td, int flags, int pages, struct proc **procp,
 	 * XXX: This is ugly; when we copy resource usage, we need to bump
 	 *      per-cred resource counters.
 	 */
-	newproc->p_ucred = p1->p_ucred;
+	proc_set_cred(newproc, p1->p_ucred);
 
 	/*
 	 * Initialize resource accounting for the child process.
diff --git a/sys/kern/kern_jail.c b/sys/kern/kern_jail.c
index a0e4c61..5d7824d 100644
--- a/sys/kern/kern_jail.c
+++ b/sys/kern/kern_jail.c
@@ -2476,7 +2476,7 @@ do_jail_attach(struct thread *td, struct prison *pr)
 	PROC_LOCK(p);
 	oldcred = crcopysafe(p, newcred);
 	newcred->cr_prison = pr;
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	setsugid(p);
 	PROC_UNLOCK(p);
 #ifdef RACCT
diff --git a/sys/kern/kern_loginclass.c b/sys/kern/kern_loginclass.c
index b20f60b..04f6809 100644
--- a/sys/kern/kern_loginclass.c
+++ b/sys/kern/kern_loginclass.c
@@ -205,7 +205,7 @@ sys_setloginclass(struct thread *td, struct setloginclass_args *uap)
 	PROC_LOCK(p);
 	oldcred = crcopysafe(p, newcred);
 	newcred->cr_loginclass = newlc;
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 #ifdef RACCT
 	racct_proc_ucred_changed(p, oldcred, newcred);
diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c
index 03b9001..a7d4331 100644
--- a/sys/kern/kern_prot.c
+++ b/sys/kern/kern_prot.c
@@ -582,7 +582,7 @@ sys_setuid(struct thread *td, struct setuid_args *uap)
 		change_euid(newcred, uip);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 #ifdef RACCT
 	racct_proc_ucred_changed(p, oldcred, newcred);
@@ -641,7 +641,7 @@ sys_seteuid(struct thread *td, struct seteuid_args *uap)
 		change_euid(newcred, euip);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 	uifree(euip);
 	crfree(oldcred);
@@ -741,7 +741,7 @@ sys_setgid(struct thread *td, struct setgid_args *uap)
 		change_egid(newcred, gid);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 	crfree(oldcred);
 	return (0);
@@ -787,7 +787,7 @@ sys_setegid(struct thread *td, struct setegid_args *uap)
 		change_egid(newcred, egid);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 	crfree(oldcred);
 	return (0);
@@ -860,7 +860,7 @@ kern_setgroups(struct thread *td, u_int ngrp, gid_t *groups)
 		crsetgroups_locked(newcred, ngrp, groups);
 	}
 	setsugid(p);
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 	crfree(oldcred);
 	return (0);
@@ -923,7 +923,7 @@ sys_setreuid(register struct thread *td, struct setreuid_args *uap)
 		change_svuid(newcred, newcred->cr_uid);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 #ifdef RACCT
 	racct_proc_ucred_changed(p, oldcred, newcred);
@@ -990,7 +990,7 @@ sys_setregid(register struct thread *td, struct setregid_args *uap)
 		change_svgid(newcred, newcred->cr_groups[0]);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 	crfree(oldcred);
 	return (0);
@@ -1064,7 +1064,7 @@ sys_setresuid(register struct thread *td, struct setresuid_args *uap)
 		change_svuid(newcred, suid);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 #ifdef RACCT
 	racct_proc_ucred_changed(p, oldcred, newcred);
@@ -1143,7 +1143,7 @@ sys_setresgid(register struct thread *td, struct setresgid_args *uap)
 		change_svgid(newcred, sgid);
 		setsugid(p);
 	}
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 	crfree(oldcred);
 	return (0);
@@ -1956,6 +1956,31 @@ cred_update_thread(struct thread *td)
 		crfree(cred);
 }
 
+/*
+ * Change process credentials.
+ * Callers are responsible for providing the reference for current credentials
+ * and for freeing old ones.
+ *
+ * Process has to be locked except when it does not have credentials (as it
+ * should not be visible just yet) or when newcred is NULL (as this can be
+ * only used when the process is about to be freed, at which point it should
+ * not be visible anymore).
+ */
+struct ucred *
+proc_set_cred(struct proc *p, struct ucred *newcred)
+{
+	struct ucred *oldcred;
+
+	if (newcred == NULL)
+		MPASS(p->p_state == PRS_ZOMBIE);
+	else if (p->p_ucred != NULL)
+		PROC_LOCK_ASSERT(p, MA_OWNED);
+
+	oldcred = p->p_ucred;
+	p->p_ucred = newcred;
+	return (oldcred);
+}
+
 struct ucred *
 crcopysafe(struct proc *p, struct ucred *cr)
 {
diff --git a/sys/kern/sys_capability.c b/sys/kern/sys_capability.c
index b309905..b3dc1b5 100644
--- a/sys/kern/sys_capability.c
+++ b/sys/kern/sys_capability.c
@@ -105,7 +105,7 @@ sys_cap_enter(struct thread *td, struct cap_enter_args *uap)
 	oldcred = p->p_ucred;
 	crcopy(newcred, oldcred);
 	newcred->cr_flags |= CRED_FLAG_CAPMODE;
-	p->p_ucred = newcred;
+	proc_set_cred(p, newcred);
 	PROC_UNLOCK(p);
 	crfree(oldcred);
 	return (0);