On 06/12/2013 04:26 AM, Bernhard Reutner-Fischer wrote:
On Fri, Jun 07, 2013 at 02:13:58PM +0800, qi.c...@windriver.com wrote:
From: Chen Qi <qi.c...@windriver.com>

This patch enables us to split the busybox into two binaries, one
containing suid applications, and the other containing nosuid apps.

Add a variable, BUSYBOX_SPLIT_SUID, to control whether to split the
busybox binary into two parts. We default it to "1" to enable the
splitting, but users could still override it to disable the splitting.
After all, busybox has no internal support for this suid apps splitting,
so there might be users out there who want just one busybox binary.

Add a configuration file, suid_config_list, to control which applications
should be splitted into the suid binary. The list is first obtained from
the information in include/applets.h. Some extra config items are also
added to the list as they are related to the suid apps. I choose to use
a configuration file here because if some config item is missed, we could
add it to the list easily.

[YOCTO #4207]

Signed-off-by: Chen Qi <qi.c...@windriver.com>
---
.../busybox/busybox-1.20.2/suid_config_list        |   48 +++++++++
meta/recipes-core/busybox/busybox.inc              |  104 +++++++++++++++-----
meta/recipes-core/busybox/busybox_1.20.2.bb        |    3 +-
3 files changed, 127 insertions(+), 28 deletions(-)
create mode 100644 meta/recipes-core/busybox/busybox-1.20.2/suid_config_list

diff --git a/meta/recipes-core/busybox/busybox-1.20.2/suid_config_list 
b/meta/recipes-core/busybox/busybox-1.20.2/suid_config_list
new file mode 100644
index 0000000..16a0b76
--- /dev/null
+++ b/meta/recipes-core/busybox/busybox-1.20.2/suid_config_list
@@ -0,0 +1,48 @@
+# This file lists all config items which are related to suid apps in busybox.
+# The following list is obtained with the command below (splitted into two 
lines for readability).
+# for i in `grep -E "APPLET.*BB_SUID_((MAYBE|REQUIRE))" include/applets.h | 
grep -v _BB_SUID_DROP |
+# cut -f 3 -d '(' | cut -f 1 -d ','`; do grep -i -E "config_(feature_|)$i(_| 
)" .config; done | cut -d' ' -f2
+CONFIG_PING
+CONFIG_PING6
+CONFIG_CRONTAB
+CONFIG_FINDFS
+CONFIG_LOGIN
+CONFIG_LOGIN_SESSION_AS_CHILD
+CONFIG_LOGIN_SCRIPTS
+CONFIG_MOUNT
+CONFIG_FEATURE_MOUNT_FAKE
+CONFIG_FEATURE_MOUNT_VERBOSE
+CONFIG_FEATURE_MOUNT_HELPERS
+CONFIG_FEATURE_MOUNT_LABEL
+CONFIG_FEATURE_MOUNT_NFS
+CONFIG_FEATURE_MOUNT_CIFS
+CONFIG_FEATURE_MOUNT_FLAGS
+CONFIG_FEATURE_MOUNT_FSTAB
+CONFIG_FEATURE_MOUNT_LOOP
+CONFIG_FEATURE_MOUNT_LOOP_CREATE
+CONFIG_PASSWD
+CONFIG_FEATURE_PASSWD_WEAK_CHECK
+CONFIG_SU
+CONFIG_FEATURE_SU_SYSLOG
+CONFIG_FEATURE_SU_CHECKS_SHELLS
+CONFIG_TRACEROUTE
+CONFIG_FEATURE_TRACEROUTE_VERBOSE
+CONFIG_FEATURE_TRACEROUTE_SOURCE_ROUTE
+CONFIG_FEATURE_TRACEROUTE_USE_ICMP
+CONFIG_TRACEROUTE6
+CONFIG_VLOCK
+CONFIG_WALL
+
+# The following list is obtained by examining the Config.in file in busybox 
manually.
+# These config items are also related to suid apps.
+CONFIG_FEATURE_FANCY_PING
+CONFIG_FEATURE_SHADOWPASSWDS
+CONFIG_USE_BB_PWD_GRP
+CONFIG_USE_BB_SHADOW
+CONFIG_USE_BB_CRYPT
+CONFIG_USE_BB_CRYPT_SHA
+CONFIG_PAM
+CONFIG_FEATURE_NOLOGIN
+CONFIG_FEATURE_SECURETTY
+CONFIG_CRYPTPW
+CONFIG_CHPASSWD
diff --git a/meta/recipes-core/busybox/busybox.inc 
b/meta/recipes-core/busybox/busybox.inc
index 99d4e99..9984c5a 100644
--- a/meta/recipes-core/busybox/busybox.inc
+++ b/meta/recipes-core/busybox/busybox.inc
@@ -12,6 +12,9 @@ LIC_FILES_CHKSUM = 
"file://LICENSE;md5=de10de48642ab74318e893a61105afbb"

SECTION = "base"

+# Whether to split the suid apps into a seperate binary
+BUSYBOX_SPLIT_SUID ?= "1"
+
export EXTRA_CFLAGS = "${CFLAGS}"
export EXTRA_LDFLAGS = "${LDFLAGS}"

@@ -136,19 +139,52 @@ do_configure () {

do_compile() {
        unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS
-       oe_runmake busybox_unstripped
-       cp busybox_unstripped busybox
+       if [ "${BUSYBOX_SPLIT_SUID}" = "1" -a x`grep 
"CONFIG_FEATURE_INDIVIDUAL=y" .config` = x ]; then
+       # split the .config into two parts, and make two busybox binaries
Hi Bernhard,

Thank you very much for your review and suggestions!
I went through your methods below very carefully and I tried your patch out.

Here are two problems.

1) The config_list.suid could be derived by renaming the `original suid_config_list' file, but what about the config_list.nosuid? We have a suid_config_list, because compared with the non-suid apps, the amount of config items for suid apps or related to suid apps are relatively small. It seems that config_list.nosuid will be a very long list.

2) Your patch in the attachment worked out well. `make busybox.applets.suid' generates a file named busybox.applets.suid which contains the following config items.
CONFIG_LOGIN
CONFIG_PASSWD
CONFIG_FEATURE_PASSWD_WEAK_CHECK
CONFIG_SU
CONFIG_FEATURE_SU_SYSLOG
CONFIG_FEATURE_SU_CHECKS_SHELLS
CONFIG_VLOCK
CONFIG_FINDFS
CONFIG_MOUNT
CONFIG_FEATURE_MOUNT_FAKE
CONFIG_FEATURE_MOUNT_VERBOSE
CONFIG_FEATURE_MOUNT_LABEL
CONFIG_FEATURE_MOUNT_CIFS
CONFIG_FEATURE_MOUNT_FLAGS
CONFIG_FEATURE_MOUNT_FSTAB
CONFIG_FEATURE_MOUNT_LOOP
CONFIG_FEATURE_MOUNT_LOOP_CREATE
CONFIG_CRONTAB
CONFIG_WALL
CONFIG_PING
CONFIG_PING6
CONFIG_TRACEROUTE
CONFIG_TRACEROUTE6
CONFIG_FEATURE_TRACEROUTE_VERBOSE

You see, this is a subset of the suid_config_list. As stated in the file's comments, part of the list is obtained from a command, and part of it is obtained by manually examine the Config.in files to find out the config items that are related to suid apps.

Best Regards,
Chen Qi
cat .config > .config-oe-full
# it would be nice to 'for s in suid nosuid'
# but that would mean operating on ${s}_config_list which bitbake (IIRC)
# ruins. Better rename the files to config_list.suid to be able to loop.
#
for s in suid nosuid; do
   egrep ^CONFIG_ ${WORKDIR}/config_list.$s | while read i; do
     grep -w "$i" .config
   done > .config.$s

   # populate the config, default everything else to no
   KCONFIG_ALLCONFIG=config.$s make allnoconfig
   oe_runmake busybox_unstripped busybox.links
   mv busybox_unstripped busybox.$s
   mv busybox.links busybox.links.$s
done
cat .config-oe-full > .config

I would much prefer to make the generation of the suid cfg stuff more
robust. Could you live with the attached helper thing (untested)?
That would make it a prepended oe_runmake busybox.applets.suid to
generate the list busybox.applets.suid. If that suits your needs we can
apply it to busybox for general use..
The other possibility is, obviously, to fit all this in busybox' build
itself, but given that we do have a seemingly working, bugless suid
handling this might be better suited to be dealt with by the user as you
suggest here.

Thoughts?
thanks,
+               cp .config .config.orig
+               oe_runmake allnoconfig
+               cp .config .config.allno
+               for item in `grep 'CONFIG_' ${WORKDIR}/suid_config_list`; do
+                       echo "# $item is not set" >> .config.nosuid.tmp
+                       grep -w "$item" .config.orig >> .config.suid.tmp
+               done
+               merge_config.sh -m .config.orig .config.nosuid.tmp
+               cp .config .config.nosuid
+               merge_config.sh -m .config.allno .config.suid.tmp
+               cp .config .config.suid
+
+               # compile with no suid apps
+               cp .config.nosuid .config
+               oe_runmake busybox_unstripped
+               cp busybox_unstripped busybox.nosuid
+               oe_runmake busybox.links
+               cp busybox.links busybox.links.nosuid
+
+               # compile with suid apps
+               cp .config.suid .config
+               oe_runmake busybox_unstripped
+               cp busybox_unstripped busybox.suid
+               oe_runmake busybox.links
+               cp busybox.links busybox.links.suid
+
+               # copy .config.orig back to .config, because the install 
process may check this file
+               cp .config.orig .config
+
+               # cleanup
+               rm .config.orig .config.nosuid.tmp .config.allno 
.config.suid.tmp .config.nosuid .config.suid
+       else
+               oe_runmake busybox_unstripped
+               cp busybox_unstripped busybox
+               oe_runmake busybox.links
+       fi
}

do_install () {
-       oe_runmake busybox.links
        if [ "${prefix}" != "/usr" ]; then
-               sed "s:^/usr/:${prefix}/:" busybox.links > busybox.links.new
-               mv busybox.links.new busybox.links
+               sed -i "s:^/usr/:${prefix}/:" busybox.links*
        fi
        if [ "${base_sbindir}" != "/sbin" ]; then
-               sed "s:^/sbin/:${base_sbindir}/:" busybox.links > 
busybox.links.new
-               mv busybox.links.new busybox.links
+               sed "s:^/sbin/:${base_sbindir}/:" busybox.links*
        fi

        install -d ${D}${sysconfdir}/init.d
@@ -157,12 +193,21 @@ do_install () {
                # Install /bin/busybox, and the /bin/sh link so the postinst 
script
                # can run. Let update-alternatives handle the rest.
                install -d ${D}${base_bindir}
-               if grep -q "CONFIG_FEATURE_SUID=y" ${B}/.config; then
-                       install -m 4755 ${B}/busybox ${D}${base_bindir}
+               if [ "${BUSYBOX_SPLIT_SUID}" = "1" ]; then
+                       install -m 4755 ${B}/busybox.suid ${D}${base_bindir}
+                       install -m 0755 ${B}/busybox.nosuid ${D}${base_bindir}
+                       install -m 0644 ${S}/busybox.links.suid 
${D}${sysconfdir}
+                       install -m 0644 ${S}/busybox.links.nosuid 
${D}${sysconfdir}
+                       ln -sf busybox.nosuid ${D}${base_bindir}/sh
                else
-                       install -m 0755 ${B}/busybox ${D}${base_bindir}
+                       if grep -q "CONFIG_FEATURE_SUID=y" ${B}/.config; then
+                               install -m 4755 ${B}/busybox ${D}${base_bindir}
+                       else
+                               install -m 0755 ${B}/busybox ${D}${base_bindir}
+                       fi
+                       install -m 0644 ${S}/busybox.links ${D}${sysconfdir}
+                       ln -sf busybox ${D}${base_bindir}/sh
                fi
-               ln -sf busybox ${D}${base_bindir}/sh
        else
                install -d ${D}${base_bindir} ${D}${base_sbindir}
                install -d ${D}${libdir} ${D}${bindir} ${D}${sbindir}
@@ -181,6 +226,7 @@ do_install () {
                if [ -f ${D}/linuxrc.${BPN} ]; then
                        mv ${D}/linuxrc.${BPN} ${D}/linuxrc
                fi
+               install -m 0644 ${S}/busybox.links ${D}${sysconfdir}
        fi

        if grep -q "CONFIG_SYSLOGD=y" ${B}/.config; then
@@ -217,7 +263,6 @@ do_install () {
                        install -m 644 ${WORKDIR}/mdev.conf 
${D}${sysconfdir}/mdev.conf
                fi
        fi
-       install -m 0644 ${S}/busybox.links ${D}${sysconfdir}

     if ${@base_contains('DISTRO_FEATURES','systemd','true','false',d)}; then
         install -d ${D}${systemd_unitdir}/system
@@ -248,22 +293,27 @@ python do_package_prepend () {

     dvar = d.getVar('D', True)
     pn = d.getVar('PN', True)
-    f = open('%s/etc/busybox.links' % (dvar), 'r')
-
-    if os.path.exists('%s/bin/busybox' % (dvar)):
-        d.setVar('ALTERNATIVE_TARGET', "/bin/busybox")
-
-    for alt_link_name in f:
-        alt_link_name = alt_link_name.strip()
-        alt_name = os.path.basename(alt_link_name)
-
-        # Match coreutils
-        if alt_name == '[':
-            alt_name = 'lbracket'

-        d.appendVar('ALTERNATIVE_%s' % (pn), ' ' + alt_name)
-        d.setVarFlag('ALTERNATIVE_LINK_NAME', alt_name, alt_link_name)
-    f.close()
+    def set_alternative_vars(links, target):
+        f = open('%s%s' % (dvar, links), 'r')
+        for alt_link_name in f:
+            alt_link_name = alt_link_name.strip()
+            alt_name = os.path.basename(alt_link_name)
+            # Match coreutils
+            if alt_name == '[':
+                alt_name = 'lbracket'
+            d.appendVar('ALTERNATIVE_%s' % (pn), ' ' + alt_name)
+            d.setVarFlag('ALTERNATIVE_LINK_NAME', alt_name, alt_link_name)
+            if os.path.exists('%s%s' % (dvar, target)):
+                d.setVarFlag('ALTERNATIVE_TARGET', alt_name, target)
+        f.close()
+        return
+
+    if os.path.exists('%s/etc/busybox.links' % (dvar)):
+        set_alternative_vars("/etc/busybox.links", "/bin/busybox")
+    else:
+        set_alternative_vars("/etc/busybox.links.nosuid", 
"/bin/busybox.nosuid")
+        set_alternative_vars("/etc/busybox.links.suid", "/bin/busybox.suid")
}

pkg_prerm_${PN} () {
diff --git a/meta/recipes-core/busybox/busybox_1.20.2.bb 
b/meta/recipes-core/busybox/busybox_1.20.2.bb
index 3ff8a88..511f1f8 100644
--- a/meta/recipes-core/busybox/busybox_1.20.2.bb
+++ b/meta/recipes-core/busybox/busybox_1.20.2.bb
@@ -36,7 +36,8 @@ SRC_URI = 
"http://www.busybox.net/downloads/busybox-${PV}.tar.bz2;name=tarball \
            file://busybox-sulogin-empty-root-password.patch \
            file://inetd.conf \
            file://inetd \
-           file://login-utilities.cfg"
+           file://login-utilities.cfg \
+           file://suid_config_list"

SRC_URI[tarball.md5sum] = "e025414bc6cd79579cc7a32a45d3ae1c"
SRC_URI[tarball.sha256sum] = 
"eb13ff01dae5618ead2ef6f92ba879e9e0390f9583bd545d8789d27cf39b6882"
--
1.7.9.5

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