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PR/45393: Greg A. Woods: The mount point validation code (that looks for

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nocoredump filesystems to avoid dumping on them) only worked for core
filenames that dump in the current working directory. Update the code to
validate the mount point of the parent directory of the core file if needed.
This commit is contained in:
christos 2011-09-23 00:03:29 +00:00
parent afeabb041e
commit eae1c5542c
1 changed files with 46 additions and 22 deletions
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68
sys/kern/kern_core.c
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@ -1,4 +1,4 @@
/* $NetBSD: kern_core.c,v 1.18 2011/04/29 22:57:54 rmind Exp $ */
/* $NetBSD: kern_core.c,v 1.19 2011/09/23 00:03:29 christos Exp $ */
/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_core.c,v 1.18 2011/04/29 22:57:54 rmind Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_core.c,v 1.19 2011/09/23 00:03:29 christos Exp $");
#include <sys/param.h>
#include <sys/vnode.h>
@ -102,7 +102,7 @@ coredump(struct lwp *l, const char *pattern)
struct coredump_iostate io;
struct plimit *lim;
int error, error1;
char *name;
char *name, *lastslash;
name = PNBUF_GET();
@ -132,24 +132,6 @@ coredump(struct lwp *l, const char *pattern)
kauth_cred_hold(p->p_cred);
cred = p->p_cred;
/*
* The core dump will go in the current working directory. Make
* sure that the directory is still there and that the mount flags
* allow us to write core dumps there.
*
* XXX: this is partially bogus, it should be checking the directory
* into which the file is actually written - which probably needs
* a flag on namei()
*/
vp = p->p_cwdi->cwdi_cdir;
if (vp->v_mount == NULL ||
(vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0) {
error = EPERM;
mutex_exit(p->p_lock);
mutex_exit(proc_lock);
goto done;
}
/*
* Make sure the process has not set-id, to prevent data leaks,
* unless it was specifically requested to allow set-id coredumps.
@ -173,10 +155,52 @@ coredump(struct lwp *l, const char *pattern)
error = coredump_buildname(p, name, pattern, MAXPATHLEN);
mutex_exit(&lim->pl_lock);
/*
* On a simple filename, see if the filesystem allow us to write
* core dumps there.
*/
lastslash = strrchr(name, '/');
if (!lastslash) {
vp = p->p_cwdi->cwdi_cdir;
if (vp->v_mount == NULL ||
(vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
error = EPERM;
}
mutex_exit(p->p_lock);
mutex_exit(proc_lock);
if (error) {
if (error)
goto done;
/*
* On a complex filename, see if the filesystem allow us to write
* core dumps there.
*
* XXX: We should have an API that avoids double lookups
*/
if (lastslash) {
char c[2];
if (lastslash - name >= MAXPATHLEN - 2) {
error = EPERM;
goto done;
}
c[0] = lastslash[1];
c[1] = lastslash[2];
lastslash[1] = '.';
lastslash[2] = '\0';
error = namei_simple_kernel(name, NSM_FOLLOW_NOEMULROOT, &vp);
if (error)
goto done;
if (vp->v_mount == NULL ||
(vp->v_mount->mnt_flag & MNT_NOCOREDUMP) != 0)
error = EPERM;
vrele(vp);
if (error)
goto done;
lastslash[1] = c[0];
lastslash[2] = c[1];
}
pb = pathbuf_create(name);