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- Change the first argument of ktrcanset(), ktrsetchildren(), and ktrops()

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to a thread pointer so that ktrcanset() can use td_ucred.
- Add some proc locking to partially protect p_tracep and p_traceflag.
This commit is contained in:
John Baldwin 2002-04-13 22:54:18 +00:00
parent 0301e9c83b
commit a7ff744350
1 changed files with 57 additions and 32 deletions
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89
sys/kern/kern_ktrace.c
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@ -57,9 +57,9 @@ static MALLOC_DEFINE(M_KTRACE, "KTRACE", "KTRACE");
#ifdef KTRACE
static struct ktr_header *ktrgetheader(int type);
static void ktrwrite(struct vnode *, struct ktr_header *, struct uio *);
static int ktrcanset(struct proc *,struct proc *);
static int ktrsetchildren(struct proc *,struct proc *,int,int,struct vnode *);
static int ktrops(struct proc *,struct proc *,int,int,struct vnode *);
static int ktrcanset(struct thread *, struct proc *);
static int ktrsetchildren(struct thread *, struct proc *, int, int, struct vnode *);
static int ktrops(struct thread *, struct proc *, int, int, struct vnode *);
static struct ktr_header *
@ -325,16 +325,20 @@ ktrace(td, uap)
if (ops == KTROP_CLEARFILE) {
sx_slock(&allproc_lock);
LIST_FOREACH(p, &allproc, p_list) {
PROC_LOCK(p);
if (p->p_tracep == vp) {
if (ktrcanset(curp, p) && p->p_tracep == vp) {
if (ktrcanset(td, p) && p->p_tracep == vp) {
p->p_tracep = NULL;
p->p_traceflag = 0;
PROC_UNLOCK(p);
(void) vn_close(vp, FREAD|FWRITE,
td->td_ucred, td);
} else {
PROC_UNLOCK(p);
error = EPERM;
}
}
} else
PROC_UNLOCK(p);
}
sx_sunlock(&allproc_lock);
goto done;
@ -367,9 +371,9 @@ ktrace(td, uap)
PGRP_UNLOCK(pg);
LIST_FOREACH(p, &pg->pg_members, p_pglist)
if (descend)
ret |= ktrsetchildren(curp, p, ops, facs, vp);
ret |= ktrsetchildren(td, p, ops, facs, vp);
else
ret |= ktrops(curp, p, ops, facs, vp);
ret |= ktrops(td, p, ops, facs, vp);
PGRPSESS_SUNLOCK();
} else {
/*
@ -381,10 +385,11 @@ ktrace(td, uap)
goto done;
}
PROC_UNLOCK(p);
/* XXX: UNLOCK above has a race */
if (descend)
ret |= ktrsetchildren(curp, p, ops, facs, vp);
ret |= ktrsetchildren(td, p, ops, facs, vp);
else
ret |= ktrops(curp, p, ops, facs, vp);
ret |= ktrops(td, p, ops, facs, vp);
}
if (!ret)
error = EPERM;
@ -442,31 +447,32 @@ utrace(td, uap)
#ifdef KTRACE
static int
ktrops(curp, p, ops, facs, vp)
struct proc *p, *curp;
ktrops(td, p, ops, facs, vp)
struct thread *td;
struct proc *p;
int ops, facs;
struct vnode *vp;
{
struct vnode *vtmp = NULL, *newvp = NULL;
if (!ktrcanset(curp, p))
PROC_LOCK(p);
if (!ktrcanset(td, p)) {
PROC_UNLOCK(p);
return (0);
}
if (ops == KTROP_SET) {
if (p->p_tracep != vp) {
struct vnode *vtmp;
/*
* if trace file already in use, relinquish
* if trace file already in use, relinquish below
*/
VREF(vp);
while ((vtmp = p->p_tracep) != NULL) {
p->p_tracep = NULL;
vrele(vtmp);
}
p->p_tracep = vp;
newvp = vp;
vtmp = p->p_tracep;
p->p_tracep = NULL;
}
p->p_traceflag |= facs;
/* XXX: Not safe */
if (curp->p_ucred->cr_uid == 0)
if (td->td_ucred->cr_uid == 0)
p->p_traceflag |= KTRFAC_ROOT;
} else {
/* KTROP_CLEAR */
@ -475,19 +481,36 @@ ktrops(curp, p, ops, facs, vp)
/* no more tracing */
p->p_traceflag = 0;
if ((vtmp = p->p_tracep) != NULL) {
p->p_tracep = NULL;
vrele(vtmp);
}
vtmp = p->p_tracep;
p->p_tracep = NULL;
}
}
PROC_UNLOCK(p);
/* Release old trace file if requested. */
if (vtmp != NULL)
vrele(vtmp);
/* Setup new trace file if requested. */
/*
* XXX: Doing this before the PROC_UNLOCK above would result in
* fewer lock operations but would break old behavior where the
* above vrele() would not be traced when changing trace files.
*/
if (newvp != NULL) {
VREF(newvp);
PROC_LOCK(p);
p->p_tracep = newvp;
PROC_UNLOCK(p);
}
return (1);
}
static int
ktrsetchildren(curp, top, ops, facs, vp)
struct proc *curp, *top;
ktrsetchildren(td, top, ops, facs, vp)
struct thread *td;
struct proc *top;
int ops, facs;
struct vnode *vp;
{
@ -497,7 +520,7 @@ ktrsetchildren(curp, top, ops, facs, vp)
p = top;
sx_slock(&proctree_lock);
for (;;) {
ret |= ktrops(curp, p, ops, facs, vp);
ret |= ktrops(td, p, ops, facs, vp);
/*
* If this process has children, descend to them next,
* otherwise do any siblings, and if done with this level,
@ -589,15 +612,17 @@ ktrwrite(vp, kth, uio)
* so, only root may further change it.
*/
static int
ktrcanset(callp, targetp)
struct proc *callp, *targetp;
ktrcanset(td, targetp)
struct thread *td;
struct proc *targetp;
{
PROC_LOCK_ASSERT(targetp, MA_OWNED);
if (targetp->p_traceflag & KTRFAC_ROOT &&
suser_cred(callp->p_ucred, PRISON_ROOT))
suser_cred(td->td_ucred, PRISON_ROOT))
return (0);
if (p_candebug(callp, targetp) != 0)
if (p_candebug(td->td_proc, targetp) != 0)
return (0);
return (1);