File: 055_pam_unix_nullok_secure

package info (click to toggle)
pam 1.1.8-3.6
  • links: PTS, VCS
  • area: main
  • in suites: stretch
  • size: 11,800 kB
  • ctags: 2,930
  • sloc: ansic: 31,350; xml: 21,611; sh: 11,344; makefile: 1,563; perl: 893; yacc: 408; lex: 70; sed: 16
file content (223 lines) | stat: -rw-r--r-- 8,604 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
Debian patch to add a new 'nullok_secure' option to pam_unix, which
accepts users with null passwords only when the applicant is connected
from a tty listed in /etc/securetty.

Authors: Sam Hartman <hartmans@debian.org>,
         Steve Langasek <vorlon@debian.org>

Upstream status: not yet submitted

Index: pam.debian/modules/pam_unix/support.c
===================================================================
--- pam.debian.orig/modules/pam_unix/support.c
+++ pam.debian/modules/pam_unix/support.c
@@ -189,13 +189,22 @@
 	/* now parse the arguments to this module */
 
 	for (; argc-- > 0; ++argv) {
+		int sl;
 
 		D(("pam_unix arg: %s", *argv));
 
 		for (j = 0; j < UNIX_CTRLS_; ++j) {
-			if (unix_args[j].token
-			    && !strncmp(*argv, unix_args[j].token, strlen(unix_args[j].token))) {
-				break;
+			if (unix_args[j].token) {
+			    sl = strlen(unix_args[j].token);
+			    if (unix_args[j].token[sl-1] == '=') {
+				/* exclude argument from comparison */
+				if (!strncmp(*argv, unix_args[j].token, sl))
+				    break;
+			    } else {
+				/* compare full strings */
+				if (!strcmp(*argv, unix_args[j].token))
+				    break;
+			    }
 			}
 		}
 
@@ -565,6 +574,7 @@
     child = fork();
     if (child == 0) {
         int i=0;
+        int nullok = off(UNIX__NONULL, ctrl);
         struct rlimit rlim;
 	static char *envp[] = { NULL };
 	char *args[] = { NULL, NULL, NULL, NULL };
@@ -595,7 +605,18 @@
 	/* exec binary helper */
 	args[0] = strdup(CHKPWD_HELPER);
 	args[1] = x_strdup(user);
-	if (off(UNIX__NONULL, ctrl)) {	/* this means we've succeeded */
+
+	if (on(UNIX_NULLOK_SECURE, ctrl)) {
+	    const void *uttyname;
+	    retval = pam_get_item(pamh, PAM_TTY, &uttyname);
+	    if (retval != PAM_SUCCESS || uttyname == NULL
+	        || _pammodutil_tty_secure(pamh, (const char *)uttyname) != PAM_SUCCESS)
+	    {
+	        nullok = 0;
+	    }
+	}
+
+	if (nullok) {
 	  args[2]=strdup("nullok");
 	} else {
 	  args[2]=strdup("nonull");
@@ -675,6 +696,17 @@
 	if (on(UNIX__NONULL, ctrl))
 		return 0;	/* will fail but don't let on yet */
 
+	if (on(UNIX_NULLOK_SECURE, ctrl)) {
+		int retval2;
+		const void *uttyname;
+		retval2 = pam_get_item(pamh, PAM_TTY, &uttyname);
+		if (retval2 != PAM_SUCCESS || uttyname == NULL)
+			return 0;
+
+		if (_pammodutil_tty_secure(pamh, (const char *)uttyname) != PAM_SUCCESS)
+			return 0;
+	}
+
 	/* UNIX passwords area */
 
 	retval = get_pwd_hash(pamh, name, &pwd, &salt);
@@ -761,7 +793,8 @@
 			}
 		}
 	} else {
-		retval = verify_pwd_hash(p, salt, off(UNIX__NONULL, ctrl));
+		retval = verify_pwd_hash(p, salt,
+		                         _unix_blankpasswd(pamh, ctrl, name));
 	}
 
 	if (retval == PAM_SUCCESS) {
Index: pam.debian/modules/pam_unix/support.h
===================================================================
--- pam.debian.orig/modules/pam_unix/support.h
+++ pam.debian/modules/pam_unix/support.h
@@ -98,8 +98,9 @@
 #define UNIX_BLOWFISH_PASS       26	/* new password hashes will use blowfish */
 #define UNIX_MIN_PASS_LEN        27	/* min length for password */
 #define UNIX_OBSCURE_CHECKS      28	/* enable obscure checks on passwords */
+#define UNIX_NULLOK_SECURE       29	/* NULL passwords allowed only on secure ttys */
 /* -------------- */
-#define UNIX_CTRLS_              29	/* number of ctrl arguments defined */
+#define UNIX_CTRLS_              30	/* number of ctrl arguments defined */
 
 #define UNIX_DES_CRYPT(ctrl)	(off(UNIX_MD5_PASS,ctrl)&&off(UNIX_BIGCRYPT,ctrl)&&off(UNIX_SHA256_PASS,ctrl)&&off(UNIX_SHA512_PASS,ctrl)&&off(UNIX_BLOWFISH_PASS,ctrl))
 
@@ -117,7 +118,7 @@
 /* UNIX_NOT_SET_PASS */    {"not_set_pass",    _ALL_ON_,                 0x40, 0},
 /* UNIX__PRELIM */         {NULL,              _ALL_ON_^(0x180),         0x80, 0},
 /* UNIX__UPDATE */         {NULL,              _ALL_ON_^(0x180),        0x100, 0},
-/* UNIX__NONULL */         {NULL,              _ALL_ON_,                0x200, 0},
+/* UNIX__NONULL */         {NULL,              _ALL_ON_^(0x10000000),   0x200, 0},
 /* UNIX__QUIET */          {NULL,              _ALL_ON_,                0x400, 0},
 /* UNIX_USE_AUTHTOK */     {"use_authtok",     _ALL_ON_,                0x800, 0},
 /* UNIX_SHADOW */          {"shadow",          _ALL_ON_,               0x1000, 0},
@@ -137,6 +138,7 @@
 /* UNIX_BLOWFISH_PASS */   {"blowfish",        _ALL_ON_^(0x2C22000),0x2000000, 1},
 /* UNIX_MIN_PASS_LEN */    {"minlen=",         _ALL_ON_,            0x4000000, 0},
 /* UNIX_OBSCURE_CHECKS */  {"obscure",         _ALL_ON_,            0x8000000, 0},
+/* UNIX_NULLOK_SECURE */   {"nullok_secure",   _ALL_ON_^(0x200),   0x10000000, 0},
 };
 
 #define UNIX_DEFAULTS  (unix_args[UNIX__NONULL].flag)
@@ -172,6 +174,9 @@
 			,const char *data_name
 			,const void **pass);
 
+extern int _pammodutil_tty_secure(const pam_handle_t *pamh,
+                                  const char *uttyname);
+
 extern int _unix_run_verify_binary(pam_handle_t *pamh,
 			unsigned int ctrl, const char *user, int *daysleft);
 #endif /* _PAM_UNIX_SUPPORT_H */
Index: pam.debian/modules/pam_unix/Makefile.am
===================================================================
--- pam.debian.orig/modules/pam_unix/Makefile.am
+++ pam.debian/modules/pam_unix/Makefile.am
@@ -30,7 +30,8 @@
   pam_unix_la_LDFLAGS += -Wl,--version-script=$(srcdir)/../modules.map
 endif
 pam_unix_la_LIBADD = $(top_builddir)/libpam/libpam.la \
-	@LIBCRYPT@ @LIBSELINUX@ $(NIS_LIBS)
+	@LIBCRYPT@ @LIBSELINUX@ $(NIS_LIBS) \
+	../pam_securetty/tty_secure.lo
 
 securelib_LTLIBRARIES = pam_unix.la
 
Index: pam.debian/modules/pam_unix/README
===================================================================
--- pam.debian.orig/modules/pam_unix/README
+++ pam.debian/modules/pam_unix/README
@@ -58,7 +58,16 @@
 
     The default action of this module is to not permit the user access to a
     service if their official password is blank. The nullok argument overrides
-    this default.
+    this default and allows any user with a blank password to access the
+    service.
+
+nullok_secure
+
+    The default action of this module is to not permit the user access to a
+    service if their official password is blank. The nullok_secure argument
+    overrides this default and allows any user with a blank password to access
+    the service as long as the value of PAM_TTY is set to one of the values
+    found in /etc/securetty.
 
 try_first_pass
 
Index: pam.debian/modules/pam_unix/pam_unix.8
===================================================================
--- pam.debian.orig/modules/pam_unix/pam_unix.8
+++ pam.debian/modules/pam_unix/pam_unix.8
@@ -82,7 +82,14 @@
 .RS 4
 The default action of this module is to not permit the user access to a service if their official password is blank\&. The
 \fBnullok\fR
-argument overrides this default\&.
+argument overrides this default and allows any user with a blank password to access the service\&.
+.RE
+.PP
+\fBnullok_secure\fR
+.RS 4
+The default action of this module is to not permit the user access to a service if their official password is blank\&. The
+\fBnullok_secure\fR
+argument overrides this default and allows any user with a blank password to access the service as long as the value of PAM_TTY is set to one of the values found in /etc/securetty\&.
 .RE
 .PP
 \fBtry_first_pass\fR
Index: pam.debian/modules/pam_unix/pam_unix.8.xml
===================================================================
--- pam.debian.orig/modules/pam_unix/pam_unix.8.xml
+++ pam.debian/modules/pam_unix/pam_unix.8.xml
@@ -137,7 +137,24 @@
           <para>
             The default action of this module is to not permit the
             user access to a service if their official password is blank.
-            The <option>nullok</option> argument overrides this default.
+            The <option>nullok</option> argument overrides this default
+            and allows any user with a blank password to access the
+            service.
+          </para>
+        </listitem>
+      </varlistentry>
+      <varlistentry>
+        <term>
+          <option>nullok_secure</option>
+        </term>
+        <listitem>
+          <para>
+            The default action of this module is to not permit the
+            user access to a service if their official password is blank.
+            The <option>nullok_secure</option> argument overrides this
+            default and allows any user with a blank password to access
+            the service as long as the value of PAM_TTY is set to one of
+	    the values found in /etc/securetty.
           </para>
         </listitem>
       </varlistentry>