[YOCTO #5436] Automatic selection of static uid/gid is needed for a dynamically generated passwd and group file to have a deterministic outcome.
When a package is installed and instructs the system to add a new user or group, unless it selects a static uid/gid value, the next available uid/gid will be used. The order in which packages are installed is dynamically computed, and may change from one installation to the next. This results in a non-deterministic set of uid/gid values. Enabling USERADD_REWRITE_PARAMS, and providing a preconfigured passwd/group file will allow the continued dynamic generation of the passwd/group file on the target, but ensure a deterministic outcome. (Dynamic generation is desired so that user and groups that have no corresponding functionality are not present within the final system image.) Signed-off-by: Mark Hatle <mark.ha...@windriver.com> --- meta/classes/useradd.bbclass | 226 +++++++++++++++++++++++++++++++++++ meta/conf/local.conf.sample.extended | 24 ++++ 2 files changed, 250 insertions(+) diff --git a/meta/classes/useradd.bbclass b/meta/classes/useradd.bbclass index a60ab09..7f2c6e8 100644 --- a/meta/classes/useradd.bbclass +++ b/meta/classes/useradd.bbclass @@ -144,9 +144,235 @@ def update_useradd_after_parse(d): if not d.getVar('USERADD_PARAM_%s' % pkg, True) and not d.getVar('GROUPADD_PARAM_%s' % pkg, True) and not d.getVar('GROUPMEMS_PARAM_%s' % pkg, True): bb.fatal("%s inherits useradd but doesn't set USERADD_PARAM, GROUPADD_PARAM or GROUPMEMS_PARAM for package %s" % (d.getVar('FILE'), pkg)) +# In order to support a deterministic set of 'dynamic' users/groups, +# we need a function to reformat the params based on a static file +def update_useradd_static_config(d): + import argparse + import re + + class myArgumentParser( argparse.ArgumentParser ): + def _print_message(self, message, file=None): + bb.warn("%s - %s: %s" % (d.getVar('PN', True), pkg, message)) + + # This should never be called... + def exit(self, status=0, message=None): + message = message or ("%s - %s: useradd.bbclass: Argument parsing exited" % (d.getVar('PN', True), pkg)) + error(message) + + def error(self, message): + raise bb.build.FuncFailed(message) + + # We parse and rewrite the useradd components + def rewrite_useradd(params): + # The following comes from --help on useradd from shadow + parser = myArgumentParser(prog='useradd') + parser.add_argument("-b", "--base-dir", metavar="BASE_DIR", help="base directory for the home directory of the new account") + parser.add_argument("-c", "--comment", metavar="COMMENT", help="GECOS field of the new account") + parser.add_argument("-d", "--home-dir", metavar="HOME_DIR", help="home directory of the new account") + parser.add_argument("-D", "--defaults", help="print or change default useradd configuration", action="store_true") + parser.add_argument("-e", "--expiredate", metavar="EXPIRE_DATE", help="expiration date of the new account") + parser.add_argument("-f", "--inactive", metavar="INACTIVE", help="password inactivity period of the new account") + parser.add_argument("-g", "--gid", metavar="GROUP", help="name or ID of the primary group of the new account") + parser.add_argument("-G", "--groups", metavar="GROUPS", help="list of supplementary groups of the new account") + parser.add_argument("-k", "--skel", metavar="SKEL_DIR", help="use this alternative skeleton directory") + parser.add_argument("-K", "--key", metavar="KEY=VALUE", help="override /etc/login.defs defaults") + parser.add_argument("-l", "--no-log-init", help="do not add the user to the lastlog and faillog databases", action="store_true") + parser.add_argument("-m", "--create-home", help="create the user's home directory", action="store_true") + parser.add_argument("-M", "--no-create-home", help="do not create the user's home directory", action="store_true") + parser.add_argument("-N", "--no-user-group", help="do not create a group with the same name as the user", action="store_true") + parser.add_argument("-o", "--non-unique", help="allow to create users with duplicate (non-unique UID)", action="store_true") + parser.add_argument("-p", "--password", metavar="PASSWORD", help="encrypted password of the new account") + parser.add_argument("-R", "--root", metavar="CHROOT_DIR", help="directory to chroot into") + parser.add_argument("-r", "--system", help="create a system account", action="store_true") + parser.add_argument("-s", "--shell", metavar="SHELL", help="login shell of the new account") + parser.add_argument("-u", "--uid", metavar="UID", help="user ID of the new account") + parser.add_argument("-U", "--user-group", help="create a group with the same name as the user", action="store_true") + parser.add_argument("LOGIN", help="Login name of the new user") + + # Return a list of configuration files based on either the default + # files/passwd or the contents of USERADD_UID_TABLES + # paths are resulved via BBPATH + def get_passwd_list(d): + str = "" + bbpath = d.getVar('BBPATH', True) + passwd_tables = d.getVar('USERADD_UID_TABLES', True) + if not passwd_tables: + passwd_tables = 'files/passwd' + for conf_file in passwd_tables.split(): + str += " %s" % bb.utils.which(bbpath, conf_file) + return str + + newparams = [] + for param in re.split('''[ ]*;[ ]*(?=(?:[^'"]|'[^']*'|"[^"]*")*$)''', params): + param=param.strip() + try: + uaargs = parser.parse_args(re.split('''[ ]*(?=(?:[^'"]|'[^']*'|"[^"]*")*$)''', param)) + except: + raise bb.build.FuncFailed("%s: Unable to parse arguments for USERADD_PARAM_%s: %s" % (d.getVar('PN', True), pkg, param)) + + # files/passwd or the contents of USERADD_UID_TABLES + # Use the standard passwd layout: + # username:password:user_id:group_id:comment:home_directory:login_shell + # (we want to process in reverse order, as 'last found' in the list wins) + for conf in get_passwd_list(d).split()[::-1]: + if os.path.exists(conf): + f = open(conf, "r") + for line in f: + if line.startswith('#'): + continue + field = line.rstrip().split(":") + if field[0] == uaargs.LOGIN: + if uaargs.uid and (uaargs.uid != field[2]): + bb.warn("Changing username %s's uid from (%s) to (%s), verify configuration files!" % (uaargs.LOGIN, uaargs.uid, field[2])) + uaargs.uid = field[2] + + # By default the system has creation of the matching groups enabled + # So if explicit user-group creation is on, an implicit group is specified + # or a group -name- is specified, we need to pick the number and create + # the group using the addgroup... + if uaargs.user_group or not uaargs.gid or not uaargs.gid.isdigit(): + # Set the implicit case + if not uaargs.gid: + uaargs.gid = uaargs.LOGIN + bb.debug(2, "Adding group %s gid (%s)!" % (uaargs.gid, field[3])) + uaargs.user_group = False + groupadd = d.getVar("GROUPADD_PARAM_%s" % pkg, True) + newgroup = "-g %s %s" % (field[3], uaargs.gid) + if groupadd: + d.setVar("GROUPADD_PARAM_%s" % pkg, "%s ; %s" % (groupadd, newgroup)) + else: + d.setVar("GROUPADD_PARAM_%s" % pkg, newgroup) + + if uaargs.gid and uaargs.gid.isdigit() and (uaargs.gid != field[3]): + bb.warn("Changing groupname %s's gid from (%s) to (%s), verify configuration files!" % (uaargs.LOGIN, uaargs.gid, field[3])) + uaargs.gid = field[3] + + uaargs.comment = [uaargs.comment, "'%s'" % field[4]][field[4] != ""] + uaargs.home_dir = field[5] + uaargs.shell = field[6] + break + + # Should be an error if a specific option is set... + if d.getVar('USERADD_ERROR_DYNAMIC', True) == '1' and (not uaargs.uid or not uaargs.gid): + bb.error("%s - %s: Username %s does not have a static uid/gid defined." % (d.getVar('PN', True), pkg, uaargs.LOGIN)) + + # Reconstruct the args... + newparam = ['', ' --defaults'][uaargs.defaults] + newparam += ['', ' --base-dir %s' % uaargs.base_dir][uaargs.base_dir != None] + newparam += ['', ' --comment %s' % uaargs.comment][uaargs.comment != None] + newparam += ['', ' --home-dir %s' % uaargs.home_dir][uaargs.home_dir != None] + newparam += ['', ' --expiredata %s' % uaargs.expiredate][uaargs.expiredate != None] + newparam += ['', ' --inactive %s' % uaargs.inactive][uaargs.inactive != None] + newparam += ['', ' --gid %s' % uaargs.gid][uaargs.gid != None] + newparam += ['', ' --groups %s' % uaargs.groups][uaargs.groups != None] + newparam += ['', ' --skel %s' % uaargs.skel][uaargs.skel != None] + newparam += ['', ' --key %s' % uaargs.key][uaargs.key != None] + newparam += ['', ' --no-log-init'][uaargs.no_log_init] + newparam += ['', ' --create-home'][uaargs.create_home] + newparam += ['', ' --no-create-home'][uaargs.no_create_home] + newparam += ['', ' --no-user-group'][uaargs.no_user_group] + newparam += ['', ' --non-unique'][uaargs.non_unique] + newparam += ['', ' --password %s' % uaargs.password][uaargs.password != None] + newparam += ['', ' --root %s' % uaargs.root][uaargs.root != None] + newparam += ['', ' --system'][uaargs.system] + newparam += ['', ' --shell %s' % uaargs.shell][uaargs.shell != None] + newparam += ['', ' --uid %s' % uaargs.uid][uaargs.uid != None] + newparam += ['', ' --user-group'][uaargs.user_group] + newparam += ' %s' % uaargs.LOGIN + + newparams.append(newparam) + + return " ;".join(newparams).strip() + + # We parse and rewrite the groupadd components + def rewrite_groupadd(params): + # The following comes from --help on groupadd from shadow + parser = myArgumentParser(prog='groupadd') + parser.add_argument("-f", "--force", help="exit successfully if the group already exists, and cancel -g if the GID is already used", action="store_true") + parser.add_argument("-g", "--gid", metavar="GID", help="use GID for the new group") + parser.add_argument("-K", "--key", metavar="KEY=VALUE", help="override /etc/login.defs defaults") + parser.add_argument("-o", "--non-unique", help="allow to create groups with duplicate (non-unique) GID", action="store_true") + parser.add_argument("-p", "--password", metavar="PASSWORD", help="use this encrypted password for the new group") + parser.add_argument("-R", "--root", metavar="CHROOT_DIR", help="directory to chroot into") + parser.add_argument("-r", "--system", help="create a system account", action="store_true") + parser.add_argument("GROUP", help="Group name of the new group") + + # Return a list of configuration files based on either the default + # files/group or the contents of USERADD_GID_TABLES + # paths are resulved via BBPATH + def get_group_list(d): + str = "" + bbpath = d.getVar('BBPATH', True) + group_tables = d.getVar('USERADD_GID_TABLES', True) + if not group_tables: + group_tables = 'files/group' + for conf_file in group_tables.split(): + str += " %s" % bb.utils.which(bbpath, conf_file) + return str + + newparams = [] + for param in re.split('''[ ]*;[ ]*(?=(?:[^'"]|'[^']*'|"[^"]*")*$)''', params): + param=param.strip() + try: + gaargs = parser.parse_args(re.split('''[ ]*(?=(?:[^'"]|'[^']*'|"[^"]*")*$)''', param)) + except: + raise bb.build.FuncFailed("%s: Unable to parse arguments for GROUPADD_PARAM_%s: %s" % (d.getVar('PN', True), pkg, param)) + + # Need to iterate over layers and open the right file(s) + # Use the standard group layout: + # groupname:password:group_id:group_members + for conf in get_group_list(d).split()[::-1]: + if os.path.exists(conf): + f = open(conf, "r") + for line in f: + if line.startswith('#'): + continue + field = line.rstrip().split(":") + if field[0] == gaargs.GROUP: + if gaargs.gid and (gaargs.gid != field[2]): + bb.warn("Changing groupname %s's gid from (%s) to (%s), verify configuration files!" % (gaargs.GROUP, gaargs.gid, field[2])) + gaargs.gid = field[2] + break + + if d.getVar('USERADD_ERROR_DYNAMIC', True) == '1' and not gaargs.gid: + bb.error("%s - %s: Groupname %s does not have a static gid defined." % (d.getVar('PN', True), pkg, gaargs.GROUP)) + + # Reconstruct the args... + newparam = ['', ' --force'][gaargs.force] + newparam += ['', ' --gid %s' % gaargs.gid][gaargs.gid != None] + newparam += ['', ' --key %s' % gaargs.key][gaargs.key != None] + newparam += ['', ' --non-unique'][gaargs.non_unique] + newparam += ['', ' --password %s' % gaargs.password][gaargs.password != None] + newparam += ['', ' --root %s' % gaargs.root][gaargs.root != None] + newparam += ['', ' --system'][gaargs.system] + newparam += ' %s' % gaargs.GROUP + + newparams.append(newparam) + + return " ;".join(newparams).strip() + + # Load and process the users and groups, rewriting the adduser/addgroup params + useradd_packages = d.getVar('USERADD_PACKAGES', True) + + for pkg in useradd_packages.split(): + # Groupmems doesn't have anything we might want to change, so simply validating + # is a bit of a waste -- only process useradd/groupadd + useradd_param = d.getVar('USERADD_PARAM_%s' % pkg, True) + if useradd_param: + d.setVar('USERADD_PARAM_%s' % pkg, rewrite_useradd(useradd_param)) + + groupadd_param = d.getVar('GROUPADD_PARAM_%s' % pkg, True) + if groupadd_param: + d.setVar('GROUPADD_PARAM_%s' % pkg, rewrite_groupadd(groupadd_param)) + + + python __anonymous() { if not bb.data.inherits_class('nativesdk', d): update_useradd_after_parse(d) + + if d.getVar('USERADD_REWRITE_PARAMS', True) == '1': + update_useradd_static_config(d) } # Return a single [GROUP|USER]ADD_PARAM formatted string which includes the diff --git a/meta/conf/local.conf.sample.extended b/meta/conf/local.conf.sample.extended index 00716f9..ee8c78f 100644 --- a/meta/conf/local.conf.sample.extended +++ b/meta/conf/local.conf.sample.extended @@ -238,6 +238,30 @@ #usermod -s /bin/sh tester; \ #" +# Various packages dynamically add users and groups to the system at package +# install time. For programs that do not care what the uid/gid is of the +# resulting users/groups, the order of the install will determine the final +# uid/gid. This can lead to non-deterministic uid/gid values from one build +# to another. Use the following settings to specify that all user/group adds +# should be created based on a static passwd/group file. +# +# By default the system looks in the BBPATH for files/passwd and files/group +# the default can be overriden by spefying USERADD_UID/GID_TABLES. +# +# Note, if you change the value of the USERADD_REWRITE_PARAMS after starting +# to build. The TMPDIR may have incompatible uid/gids in it. You must 'rm' +# the TMPDIR to avoid this issue. +# +#USERADD_REWRITE_PARAMS = "1" +#USERADD_UID_TABLES = "files/passwd" +#USERADD_GID_TABLES = "files/group" +# +# In order to prevent generating a system where a dynamicly assigned uid/gid +# can exist, you can enable the following setting. This will force the +# system to error out if the user/group name is not defined in the +# files/passwd or files/group (or specified replacements.) +#USERADD_ERROR_DYNAMIC = "1" + # Enabling FORTRAN # Note this is not officially supported and is just illustrated here to # show an example of how it can be done -- 1.8.1.2.545.g2f19ada _______________________________________________ Openembedded-core mailing list Openembedded-core@lists.openembedded.org http://lists.openembedded.org/mailman/listinfo/openembedded-core