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Commit a work-around for a more general bug involving process state:

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check whether p_ucred is NULL or not in pfs_getattr() before
dereferencing the credential, and return ENOENT if there wasn't one.

This is a symptom of a larger problem, wherein pfind() can return
references to incompletely initialized processes, and we instead ought
to not return them, or check the process state before acting on the
process.

Reported by:	kris
Discussed with:	tjr, others
This commit is contained in:
Robert Watson 2004-08-13 20:27:56 +00:00
parent 19ef43daef
commit d990378077
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=133668
1 changed files with 11 additions and 0 deletions
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11
sys/fs/pseudofs/pseudofs_vnops.c
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@ -197,6 +197,17 @@ pfs_getattr(struct vop_getattr_args *va)
if (pvd->pvd_pid != NO_PID) {
if ((proc = pfind(pvd->pvd_pid)) == NULL)
PFS_RETURN (ENOENT);
/*
* XXX: pfind() returning incompletely allocated processes
* is probably a bug. Or, at least, we should check the
* process state, not the ucred pointer. Work around for
* now by checking that to avoid a possible NULL pointer
* dereference.
*/
if (proc->p_ucred == NULL) {
PROC_UNLOCK(proc);
PFS_RETURN (ENOENT);
}
vap->va_uid = proc->p_ucred->cr_ruid;
vap->va_gid = proc->p_ucred->cr_rgid;
if (pn->pn_attr != NULL)