Bug Summary

File:src/libexec/login_lchpass/login_lchpass.c
Warning:line 134, column 15
Access to field 'pw_name' results in a dereference of a null pointer (loaded from variable 'pwd')

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name login_lchpass.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/libexec/login_lchpass/obj -resource-dir /usr/local/lib/clang/13.0.0 -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -Wno-unused -fdebug-compilation-dir=/usr/src/libexec/login_lchpass/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/libexec/login_lchpass/login_lchpass.c
1/* $OpenBSD: login_lchpass.c,v 1.21 2018/04/26 12:42:51 guenther Exp $ */
2
3/*-
4 * Copyright (c) 1995,1996 Berkeley Software Design, Inc. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by Berkeley Software Design,
17 * Inc.
18 * 4. The name of Berkeley Software Design, Inc. may not be used to endorse
19 * or promote products derived from this software without specific prior
20 * written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN, INC. ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN, INC. BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * BSDI $From: login_lchpass.c,v 1.4 1997/08/08 18:58:23 prb Exp $
35 */
36
37#include <sys/resource.h>
38#include <sys/uio.h>
39
40#include <pwd.h>
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#include <syslog.h>
45#include <unistd.h>
46#include <login_cap.h>
47#include <readpassphrase.h>
48
49#define BACK_CHANNEL3 3
50
51int local_passwd(char *, int);
52
53int
54main(int argc, char *argv[])
55{
56 struct iovec iov[2];
57 struct passwd *pwd;
58 char *username = NULL((void *)0), *hash = NULL((void *)0);
59 char oldpass[1024];
60 struct rlimit rl;
61 int c;
62
63 iov[0].iov_base = BI_SILENT"reject silent";
64 iov[0].iov_len = sizeof(BI_SILENT"reject silent") - 1;
65 iov[1].iov_base = "\n";
66 iov[1].iov_len = 1;
67
68 rl.rlim_cur = 0;
69 rl.rlim_max = 0;
70 (void)setrlimit(RLIMIT_CORE4, &rl);
71
72 (void)setpriority(PRIO_PROCESS0, 0, 0);
73
74 openlog("login", LOG_ODELAY0x04, LOG_AUTH(4<<3));
75
76 while ((c = getopt(argc, argv, "v:s:")) != -1)
1
Assuming the condition is false
→
2
←
Loop condition is false. Execution continues on line 91
→
77 switch (c) {
78 case 'v':
79 break;
80 case 's': /* service */
81 if (strcmp(optarg, "login") != 0) {
82 syslog(LOG_ERR3, "%s: invalid service", optarg);
83 exit(1);
84 }
85 break;
86 default:
87 syslog(LOG_ERR3, "usage error");
88 exit(1);
89 }
90
91 switch (argc - optind) {
3
←
Control jumps to 'case 1:' at line 94
→
92 case 2:
93 /* class is not used */
94 case 1:
95 username = argv[optind];
96 break;
4
←
 Execution continues on line 102
→
97 default:
98 syslog(LOG_ERR3, "usage error");
99 exit(1);
100 }
101
102 pwd = getpwnam_shadow(username);
5
←
Value assigned to 'pwd'
→
103 if (pwd) {
6
←
Assuming 'pwd' is null
→
7
←
Taking false branch
→
104 if (pwd->pw_uid == 0) {
105 syslog(LOG_ERR3, "attempted root password change");
106 pwd = NULL((void *)0);
107 } else if (*pwd->pw_passwd == '\0') {
108 syslog(LOG_ERR3, "%s attempting to add password",
109 username);
110 pwd = NULL((void *)0);
111 }
112 }
113
114 if (pwd
7.1
'pwd' is null
)
8
←
Taking false branch
→
115 hash = pwd->pw_passwd;
116
117 (void)setpriority(PRIO_PROCESS0, 0, -4);
118
119 (void)printf("Changing local password for %s.\n", username);
120 if ((readpassphrase("Old Password:", oldpass, sizeof(oldpass),
9
←
Assuming the condition is false
→
10
←
Taking false branch
→
121 RPP_ECHO_OFF0x00)) == NULL((void *)0))
122 exit(1);
123
124 if (crypt_checkpass(oldpass, hash) != 0) {
11
←
Assuming the condition is false
→
12
←
Taking false branch
→
125 explicit_bzero(oldpass, strlen(oldpass));
126 exit(1);
127 }
128 explicit_bzero(oldpass, strlen(oldpass));
129
130 /*
131 * We rely on local_passwd() to block signals during the
132 * critical section.
133 */
134 local_passwd(pwd->pw_name, 1);
13
←
Access to field 'pw_name' results in a dereference of a null pointer (loaded from variable 'pwd')
135 (void)writev(BACK_CHANNEL3, iov, 2);
136 exit(0);
137}