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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: Pending
Signed-off-by: Ming Liu <ming.liu@windriver.com>
===================================================================
diff -urpN a/modules/pam_unix/Makefile.am b/modules/pam_unix/Makefile.am
--- a/modules/pam_unix/Makefile.am 2013-07-05 09:51:31.014483164 +0800
+++ b/modules/pam_unix/Makefile.am 2013-07-05 10:26:12.884484000 +0800
@@ -30,7 +30,8 @@ if HAVE_VERSIONING
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
diff -urpN a/modules/pam_unix/pam_unix.8 b/modules/pam_unix/pam_unix.8
--- a/modules/pam_unix/pam_unix.8 2013-07-05 09:52:16.825108201 +0800
+++ b/modules/pam_unix/pam_unix.8 2013-07-05 10:28:34.724483774 +0800
@@ -220,7 +220,14 @@ A little more extreme than debug\&.
.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
diff -urpN a/modules/pam_unix/pam_unix.8.xml b/modules/pam_unix/pam_unix.8.xml
--- a/modules/pam_unix/pam_unix.8.xml 2013-07-05 09:52:38.775108523 +0800
+++ b/modules/pam_unix/pam_unix.8.xml 2013-07-05 10:30:23.084483630 +0800
@@ -135,7 +135,24 @@
<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>
diff -urpN a/modules/pam_unix/README b/modules/pam_unix/README
--- a/modules/pam_unix/README 2013-07-05 09:51:52.205107846 +0800
+++ b/modules/pam_unix/README 2013-07-05 10:27:10.774484537 +0800
@@ -57,7 +57,16 @@ nullok
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
diff -urpN a/modules/pam_unix/support.c b/modules/pam_unix/support.c
--- a/modules/pam_unix/support.c 2013-07-05 09:50:49.134482523 +0800
+++ b/modules/pam_unix/support.c 2013-07-05 09:56:26.924484267 +0800
@@ -84,14 +84,22 @@ int _set_ctrl(pam_handle_t *pamh, int fl
/* now parse the arguments to this module */
for (; argc-- > 0; ++argv) {
- int j;
+ int j, 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;
+ }
}
}
@@ -461,6 +469,7 @@ static int _unix_run_helper_binary(pam_h
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 };
@@ -488,7 +497,18 @@ static int _unix_run_helper_binary(pam_h
/* 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");
@@ -567,6 +587,17 @@ _unix_blankpasswd (pam_handle_t *pamh, u
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);
@@ -653,7 +684,8 @@ int _unix_verify_password(pam_handle_t *
}
}
} 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) {
diff -urpN a/modules/pam_unix/support.h b/modules/pam_unix/support.h
--- a/modules/pam_unix/support.h 2013-07-05 09:51:10.385107934 +0800
+++ b/modules/pam_unix/support.h 2013-07-05 10:23:54.815107842 +0800
@@ -90,8 +90,9 @@ typedef struct {
password hash algorithms */
#define UNIX_BLOWFISH_PASS 26 /* new password hashes will use blowfish */
#define UNIX_MIN_PASS_LEN 27 /* min length for password */
+#define UNIX_NULLOK_SECURE 28 /* NULL passwords allowed only on secure ttys */
/* -------------- */
-#define UNIX_CTRLS_ 28 /* number of ctrl arguments defined */
+#define UNIX_CTRLS_ 29 /* 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))
@@ -109,7 +110,7 @@ static const UNIX_Ctrls unix_args[UNIX_C
/* UNIX_NOT_SET_PASS */ {"not_set_pass", _ALL_ON_, 0100},
/* UNIX__PRELIM */ {NULL, _ALL_ON_^(0600), 0200},
/* UNIX__UPDATE */ {NULL, _ALL_ON_^(0600), 0400},
-/* UNIX__NONULL */ {NULL, _ALL_ON_, 01000},
+/* UNIX__NONULL */ {NULL, _ALL_ON_^(0x10000000), 0x200},
/* UNIX__QUIET */ {NULL, _ALL_ON_, 02000},
/* UNIX_USE_AUTHTOK */ {"use_authtok", _ALL_ON_, 04000},
/* UNIX_SHADOW */ {"shadow", _ALL_ON_, 010000},
@@ -127,7 +128,8 @@ static const UNIX_Ctrls unix_args[UNIX_C
/* UNIX_SHA512_PASS */ {"sha512", _ALL_ON_^(0260420000), 040000000},
/* UNIX_ALGO_ROUNDS */ {"rounds=", _ALL_ON_, 0100000000},
/* UNIX_BLOWFISH_PASS */ {"blowfish", _ALL_ON_^(0260420000), 0200000000},
-/* UNIX_MIN_PASS_LEN */ {"minlen=", _ALL_ON_, 0400000000},
+/* UNIX_MIN_PASS_LEN */ {"minlen=", _ALL_ON_, 0400000000},
+/* UNIX_NULLOK_SECURE */ {"nullok_secure", _ALL_ON_^(0x200), 0x10000000},
};
#define UNIX_DEFAULTS (unix_args[UNIX__NONULL].flag)
@@ -163,6 +165,9 @@ extern int _unix_read_password(pam_handl
,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 */
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