140 lines
4.0 KiB
C
140 lines
4.0 KiB
C
/* $NetBSD: subr_exec_fd.c,v 1.12 2021/06/29 22:40:53 dholland Exp $ */
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/*-
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* Copyright (c) 2008 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: subr_exec_fd.c,v 1.12 2021/06/29 22:40:53 dholland Exp $");
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#include <sys/param.h>
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#include <sys/atomic.h>
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#include <sys/file.h>
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#include <sys/filedesc.h>
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#include <sys/mutex.h>
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#include <sys/namei.h>
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#include <sys/syslog.h>
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#include <sys/vnode.h>
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#include <sys/ktrace.h>
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void
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fd_ktrexecfd(void)
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{
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proc_t *p;
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filedesc_t *fdp;
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fdfile_t *ff;
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lwp_t *l;
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fdtab_t *dt;
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file_t *fp;
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int fd;
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l = curlwp;
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p = l->l_proc;
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fdp = p->p_fd;
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dt = atomic_load_consume(&fdp->fd_dt);
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for (fd = 0; fd <= fdp->fd_lastfile; fd++) {
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if ((ff = dt->dt_ff[fd]) == NULL) {
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KASSERT(fd >= NDFDFILE);
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continue;
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}
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KASSERT(fd >= NDFDFILE ||
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ff == (fdfile_t *)fdp->fd_dfdfile[fd]);
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if ((fp = atomic_load_consume(&ff->ff_file)) == NULL)
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continue;
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ktr_execfd(fd, fp->f_type);
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}
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}
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/*
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* It is unsafe for set[ug]id processes to be started with file
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* descriptors 0..2 closed, as these descriptors are given implicit
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* significance in the Standard C library. fd_checkstd() will create a
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* descriptor referencing /dev/null for each of stdin, stdout, and
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* stderr that is not already open.
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*/
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#define CHECK_UPTO 3
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int
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fd_checkstd(void)
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{
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struct proc *p;
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struct pathbuf *pb;
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struct vnode *vp;
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filedesc_t *fdp;
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file_t *fp;
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fdtab_t *dt;
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struct proc *pp;
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int fd, i, error, flags = FREAD|FWRITE;
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char closed[CHECK_UPTO * 3 + 1], which[3 + 1];
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p = curproc;
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closed[0] = '\0';
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if ((fdp = p->p_fd) == NULL)
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return (0);
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dt = atomic_load_consume(&fdp->fd_dt);
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for (i = 0; i < CHECK_UPTO; i++) {
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KASSERT(i >= NDFDFILE ||
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dt->dt_ff[i] == (fdfile_t *)fdp->fd_dfdfile[i]);
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if (dt->dt_ff[i]->ff_file != NULL)
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continue;
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snprintf(which, sizeof(which), ",%d", i);
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strlcat(closed, which, sizeof(closed));
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if ((error = fd_allocfile(&fp, &fd)) != 0)
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return (error);
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KASSERT(fd < CHECK_UPTO);
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pb = pathbuf_create("/dev/null");
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if (pb == NULL) {
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return ENOMEM;
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}
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error = vn_open(NULL, pb, 0, flags, 0, &vp, NULL, NULL);
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if (error != 0) {
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pathbuf_destroy(pb);
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fd_abort(p, fp, fd);
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return (error);
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}
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fp->f_type = DTYPE_VNODE;
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fp->f_vnode = vp;
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fp->f_flag = flags;
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fp->f_ops = &vnops;
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VOP_UNLOCK(vp);
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fd_affix(p, fp, fd);
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pathbuf_destroy(pb);
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}
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if (closed[0] != '\0') {
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mutex_enter(&proc_lock);
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pp = p->p_pptr;
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mutex_enter(pp->p_lock);
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log(LOG_WARNING, "set{u,g}id pid %d (%s) "
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"was invoked by uid %d ppid %d (%s) "
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"with fd %s closed\n",
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p->p_pid, p->p_comm, kauth_cred_geteuid(pp->p_cred),
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pp->p_pid, pp->p_comm, &closed[1]);
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mutex_exit(pp->p_lock);
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mutex_exit(&proc_lock);
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}
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return (0);
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}
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#undef CHECK_UPTO
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