1 /* $NetBSD: subr_exec_fd.c,v 1.7 2014/09/05 09:20:59 matt Exp $ */ 2 3 /*- 4 * Copyright (c) 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: subr_exec_fd.c,v 1.7 2014/09/05 09:20:59 matt Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/file.h> 34 #include <sys/filedesc.h> 35 #include <sys/mutex.h> 36 #include <sys/namei.h> 37 #include <sys/syslog.h> 38 #include <sys/vnode.h> 39 #include <sys/ktrace.h> 40 41 void 42 fd_ktrexecfd(void) 43 { 44 proc_t *p; 45 filedesc_t *fdp; 46 fdfile_t *ff; 47 lwp_t *l; 48 fdtab_t *dt; 49 int fd; 50 51 l = curlwp; 52 p = l->l_proc; 53 fdp = p->p_fd; 54 dt = fdp->fd_dt; 55 56 for (fd = 0; fd <= fdp->fd_lastfile; fd++) { 57 if ((ff = dt->dt_ff[fd]) == NULL) { 58 KASSERT(fd >= NDFDFILE); 59 continue; 60 } 61 KASSERT(fd >= NDFDFILE || 62 ff == (fdfile_t *)fdp->fd_dfdfile[fd]); 63 if (ff->ff_file == NULL) 64 continue; 65 ktr_execfd(fd, ff->ff_file->f_type); 66 } 67 } 68 69 /* 70 * It is unsafe for set[ug]id processes to be started with file 71 * descriptors 0..2 closed, as these descriptors are given implicit 72 * significance in the Standard C library. fdcheckstd() will create a 73 * descriptor referencing /dev/null for each of stdin, stdout, and 74 * stderr that is not already open. 75 */ 76 #define CHECK_UPTO 3 77 int 78 fd_checkstd(void) 79 { 80 struct proc *p; 81 struct pathbuf *pb; 82 struct nameidata nd; 83 filedesc_t *fdp; 84 file_t *fp; 85 fdtab_t *dt; 86 struct proc *pp; 87 int fd, i, error, flags = FREAD|FWRITE; 88 char closed[CHECK_UPTO * 3 + 1], which[3 + 1]; 89 90 p = curproc; 91 closed[0] = '\0'; 92 if ((fdp = p->p_fd) == NULL) 93 return (0); 94 dt = fdp->fd_dt; 95 for (i = 0; i < CHECK_UPTO; i++) { 96 KASSERT(i >= NDFDFILE || 97 dt->dt_ff[i] == (fdfile_t *)fdp->fd_dfdfile[i]); 98 if (dt->dt_ff[i]->ff_file != NULL) 99 continue; 100 snprintf(which, sizeof(which), ",%d", i); 101 strlcat(closed, which, sizeof(closed)); 102 if ((error = fd_allocfile(&fp, &fd)) != 0) 103 return (error); 104 KASSERT(fd < CHECK_UPTO); 105 pb = pathbuf_create("/dev/null"); 106 if (pb == NULL) { 107 return ENOMEM; 108 } 109 NDINIT(&nd, LOOKUP, FOLLOW, pb); 110 if ((error = vn_open(&nd, flags, 0)) != 0) { 111 pathbuf_destroy(pb); 112 fd_abort(p, fp, fd); 113 return (error); 114 } 115 fp->f_type = DTYPE_VNODE; 116 fp->f_vnode = nd.ni_vp; 117 fp->f_flag = flags; 118 fp->f_ops = &vnops; 119 VOP_UNLOCK(nd.ni_vp); 120 fd_affix(p, fp, fd); 121 pathbuf_destroy(pb); 122 } 123 if (closed[0] != '\0') { 124 mutex_enter(proc_lock); 125 pp = p->p_pptr; 126 mutex_enter(pp->p_lock); 127 log(LOG_WARNING, "set{u,g}id pid %d (%s) " 128 "was invoked by uid %d ppid %d (%s) " 129 "with fd %s closed\n", 130 p->p_pid, p->p_comm, kauth_cred_geteuid(pp->p_cred), 131 pp->p_pid, pp->p_comm, &closed[1]); 132 mutex_exit(pp->p_lock); 133 mutex_exit(proc_lock); 134 } 135 return (0); 136 } 137 #undef CHECK_UPTO 138