| From b6545b83f94c5fb7aec1478b8d458a1393f479c8 Mon Sep 17 00:00:00 2001 |
| From: "Maxin B. John" <maxin.john@intel.com> |
| Date: Wed, 25 May 2016 14:12:25 +0300 |
| Subject: [PATCH] pam_unix: support 'nullok_secure' option |
| |
| 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> |
| Signed-off-by: Amarnath Valluri <amarnath.valluri@intel.com> |
| Signed-off-by: Maxin B. John <maxin.john@intel.com> |
| --- |
| modules/pam_unix/Makefile.am | 3 ++- |
| modules/pam_unix/pam_unix.8.xml | 19 ++++++++++++++++++- |
| modules/pam_unix/support.c | 40 +++++++++++++++++++++++++++++++++++----- |
| modules/pam_unix/support.h | 8 ++++++-- |
| 4 files changed, 61 insertions(+), 9 deletions(-) |
| |
| diff --git a/modules/pam_unix/Makefile.am b/modules/pam_unix/Makefile.am |
| index 56df178..2bba460 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@ @TIRPC_LIBS@ @NSL_LIBS@ |
| + @LIBCRYPT@ @LIBSELINUX@ @TIRPC_LIBS@ @NSL_LIBS@ \ |
| + ../pam_securetty/tty_secure.lo |
| |
| securelib_LTLIBRARIES = pam_unix.la |
| |
| diff --git a/modules/pam_unix/pam_unix.8.xml b/modules/pam_unix/pam_unix.8.xml |
| index 1b318f1..be0330e 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 fc8595e..29e3341 100644 |
| --- a/modules/pam_unix/support.c |
| +++ b/modules/pam_unix/support.c |
| @@ -183,13 +183,22 @@ 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; |
| + } |
| } |
| } |
| |
| @@ -560,6 +569,7 @@ 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 */ |
| |
| @@ -587,7 +597,16 @@ 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"; |
| @@ -672,6 +691,17 @@ _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); |
| @@ -758,7 +788,7 @@ 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 b4c279c..8da4a8e 100644 |
| --- a/modules/pam_unix/support.h |
| +++ b/modules/pam_unix/support.h |
| @@ -98,8 +98,9 @@ typedef struct { |
| #define UNIX_QUIET 28 /* Don't print informational messages */ |
| #define UNIX_NO_PASS_EXPIRY 29 /* Don't check for password expiration if not used for authentication */ |
| #define UNIX_DES 30 /* DES, default */ |
| +#define UNIX_NULLOK_SECURE 31 /* NULL passwords allowed only on secure ttys */ |
| /* -------------- */ |
| -#define UNIX_CTRLS_ 31 /* number of ctrl arguments defined */ |
| +#define UNIX_CTRLS_ 32 /* 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 @@ static const UNIX_Ctrls unix_args[UNIX_CTRLS_] = |
| /* UNIX_AUTHTOK_TYPE */ {"authtok_type=", _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_QUIET */ {"quiet", _ALL_ON_, 01000000000, 0}, |
| /* UNIX_NO_PASS_EXPIRY */ {"no_pass_expiry", _ALL_ON_, 02000000000, 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) |
| @@ -172,6 +174,8 @@ extern int _unix_read_password(pam_handle_t * pamh |
| ,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 */ |
| -- |
| 2.4.0 |
| |