[PATCH 2/3] cred: add proc_set_cred_init helper
Mateusz Guzik
mjguzik at gmail.com
Sat Mar 21 01:00:48 UTC 2015
From: Mateusz Guzik <mjg at freebsd.org>
proc_set_cred_init can be used to set first credentials of a new
process.
Update proc_set_cred assertions so that it only expects already used
processes.
This fixes panics where p_ucred of a new process happens to be non-NULL.
---
sys/kern/init_main.c | 2 +-
sys/kern/kern_fork.c | 2 +-
sys/kern/kern_prot.c | 16 ++++++++++++++--
sys/sys/ucred.h | 1 +
4 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index 82cf63f..88cd44c 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -515,7 +515,7 @@ proc0_init(void *dummy __unused)
newcred->cr_ruidinfo = uifind(0);
newcred->cr_prison = &prison0;
newcred->cr_loginclass = loginclass_find("default");
- proc_set_cred(p, newcred);
+ proc_set_cred_init(p, newcred);
#ifdef AUDIT
audit_cred_kproc0(newcred);
#endif
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 15833fd..a3a70b8 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -867,7 +867,7 @@ 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.
*/
- proc_set_cred(newproc, crhold(td->td_ucred));
+ proc_set_cred_init(newproc, crhold(td->td_ucred));
/*
* Initialize resource accounting for the child process.
diff --git a/sys/kern/kern_prot.c b/sys/kern/kern_prot.c
index 72c9f65..9c49f71 100644
--- a/sys/kern/kern_prot.c
+++ b/sys/kern/kern_prot.c
@@ -1954,8 +1954,19 @@ cred_update_thread(struct thread *td)
}
/*
+ * Set initial process credentials.
+ * Callers are responsible for providing the reference for provided credentials.
+ */
+void
+proc_set_cred_init(struct proc *p, struct ucred *newcred)
+{
+
+ p->p_ucred = newcred;
+}
+
+/*
* Change process credentials.
- * Callers are responsible for providing the reference for current credentials
+ * Callers are responsible for providing the reference for passed credentials
* and for freeing old ones.
*
* Process has to be locked except when it does not have credentials (as it
@@ -1968,9 +1979,10 @@ proc_set_cred(struct proc *p, struct ucred *newcred)
{
struct ucred *oldcred;
+ MPASS(p->p_ucred != NULL);
if (newcred == NULL)
MPASS(p->p_state == PRS_ZOMBIE);
- else if (p->p_ucred != NULL)
+ else
PROC_LOCK_ASSERT(p, MA_OWNED);
oldcred = p->p_ucred;
diff --git a/sys/sys/ucred.h b/sys/sys/ucred.h
index 2b42b01..9a45308 100644
--- a/sys/sys/ucred.h
+++ b/sys/sys/ucred.h
@@ -106,6 +106,7 @@ void crcopy(struct ucred *dest, struct ucred *src);
struct ucred *crcopysafe(struct proc *p, struct ucred *cr);
struct ucred *crdup(struct ucred *cr);
void cred_update_thread(struct thread *td);
+void proc_set_cred_init(struct proc *p, struct ucred *cr);
struct ucred *proc_set_cred(struct proc *p, struct ucred *cr);
void crfree(struct ucred *cr);
struct ucred *crget(void);
--
2.3.2
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