From 9bdc197474795f2d000c2bc04f58f7cef8898f21 Mon Sep 17 00:00:00 2001
From: Amarnath Valluri <amarnath.valluri@intel.com>
Date: Wed, 15 Jul 2015 13:07:20 +0300
Subject: [PATCH] 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>
v2:
- Forward ported from v1.1.6 to v1.2.1
Signed-off-by: Amarnath Valluri <amarnath.valluri@intel.com>
---
modules/pam_unix/Makefile.am | 3 ++-
modules/pam_unix/README | 11 ++++++++++-
modules/pam_unix/pam_unix.8 | 9 ++++++++-
modules/pam_unix/pam_unix.8.xml | 19 ++++++++++++++++++-
modules/pam_unix/support.c | 40 +++++++++++++++++++++++++++++++++++-----
modules/pam_unix/support.h | 8 ++++++--
6 files changed, 79 insertions(+), 11 deletions(-)
diff --git a/modules/pam_unix/Makefile.am b/modules/pam_unix/Makefile.am
index 56ed591..9a372ac 100644
--- a/modules/pam_unix/Makefile.am
+++ b/modules/pam_unix/Makefile.am
@@ -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 --git a/modules/pam_unix/README b/modules/pam_unix/README
index 3935dba..7880d91 100644
--- a/modules/pam_unix/README
+++ b/modules/pam_unix/README
@@ -67,7 +67,16 @@ 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 --git a/modules/pam_unix/pam_unix.8 b/modules/pam_unix/pam_unix.8
index 339178b..a4bd906 100644
--- a/modules/pam_unix/pam_unix.8
+++ b/modules/pam_unix/pam_unix.8
@@ -92,7 +92,14 @@ Turns off informational messages namely messages about session open and close vi
.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 --git a/modules/pam_unix/pam_unix.8.xml b/modules/pam_unix/pam_unix.8.xml
index a8b64bb..1ced6f4 100644
--- a/modules/pam_unix/pam_unix.8.xml
+++ b/modules/pam_unix/pam_unix.8.xml
@@ -159,7 +159,24 @@
<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 --git a/modules/pam_unix/support.c b/modules/pam_unix/support.c
index abccd82..2361957 100644
--- a/modules/pam_unix/support.c
+++ b/modules/pam_unix/support.c
@@ -189,13 +189,22 @@ int _set_ctrl(pam_handle_t *pamh, int flags, int *remember, int *rounds,
/* 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;
+ }
}
}
@@ -566,6 +575,7 @@ static int _unix_run_helper_binary(pam_handle_t *pamh, const char *passwd,
if (child == 0) {
static char *envp[] = { NULL };
const char *args[] = { NULL, NULL, NULL, NULL };
+ int nullok = off(UNIX__NONULL, ctrl);
/* XXX - should really tidy up PAM here too */
@@ -593,7 +603,16 @@ static int _unix_run_helper_binary(pam_handle_t *pamh, const char *passwd,
/* exec binary helper */
args[0] = CHKPWD_HELPER;
args[1] = 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]="nullok";
} else {
args[2]="nonull";
@@ -678,6 +697,17 @@ _unix_blankpasswd (pam_handle_t *pamh, unsigned int ctrl, const char *name)
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);
@@ -764,7 +794,7 @@ int _unix_verify_password(pam_handle_t * pamh, const char *name
}
}
} 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 --git a/modules/pam_unix/support.h b/modules/pam_unix/support.h
index 3729ce0..43cdbea 100644
--- a/modules/pam_unix/support.h
+++ b/modules/pam_unix/support.h
@@ -99,8 +99,9 @@ typedef struct {
#define UNIX_MIN_PASS_LEN 27 /* min length for password */
#define UNIX_QUIET 28 /* Don't print informational messages */
#define UNIX_DES 29 /* DES, default */
+#define UNIX_NULLOK_SECURE 30 /* NULL passwords allowed only on secure ttys */
/* -------------- */
-#define UNIX_CTRLS_ 30 /* number of ctrl arguments defined */
+#define UNIX_CTRLS_ 31 /* 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))
@@ -118,7 +119,7 @@ static const UNIX_Ctrls unix_args[UNIX_CTRLS_] =
/* UNIX_NOT_SET_PASS */ {"not_set_pass", _ALL_ON_, 0100, 0},
/* UNIX__PRELIM */ {NULL, _ALL_ON_^(0600), 0200, 0},
/* UNIX__UPDATE */ {NULL, _ALL_ON_^(0600), 0400, 0},
-/* UNIX__NONULL */ {NULL, _ALL_ON_, 01000, 0},
+/* UNIX__NONULL */ {NULL, _ALL_ON_^(02000000000), 01000, 0},
/* UNIX__QUIET */ {NULL, _ALL_ON_, 02000, 0},
/* UNIX_USE_AUTHTOK */ {"use_authtok", _ALL_ON_, 04000, 0},
/* UNIX_SHADOW */ {"shadow", _ALL_ON_, 010000, 0},
@@ -139,6 +140,7 @@ static const UNIX_Ctrls unix_args[UNIX_CTRLS_] =
/* UNIX_MIN_PASS_LEN */ {"minlen=", _ALL_ON_, 0400000000, 0},
/* UNIX_QUIET */ {"quiet", _ALL_ON_, 01000000000, 0},
/* UNIX_DES */ {"des", _ALL_ON_^(0260420000), 0, 1},
+/* UNIX_NULLOK_SECURE */ {"nullok_secure", _ALL_ON_^(01000), 02000000000, 0},
};
#define UNIX_DEFAULTS (unix_args[UNIX__NONULL].flag)
@@ -171,6 +173,8 @@ extern int _unix_read_password(pam_handle_t * pamh
,const char *prompt2
,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);
--
2.1.4