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 | |