path: root/meta-security/recipes-connectivity/bluez5
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authorJosé Bollo <>2018-01-24 11:38:43 +0100
committerJosé Bollo <>2018-02-13 11:02:00 +0100
commitf70d712e4f505f5c5b50ae17f4f023d20a667568 (patch)
tree57b0aaa702651012e1adfc07f9b6b6c580506f66 /meta-security/recipes-connectivity/bluez5
parent3f962c7d202055777dd0238f12dbcf70f09ac07d (diff)
Integrate parts of meta-intel-iot-security
Adds the recipes of the sub layers - meta-security-framework - meta-security-smack Change-Id: I618608008a3b3d1d34adb6e38048110f13ac0643 Signed-off-by: José Bollo <>
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+# Recent bluez5 releases started limiting the capabilities of
+# bluetoothd. When running on a Smack-enabled system, that change has the
+# effect that bluetoothd can no longer create the input device under
+# /sys because bluez5 running with label "System" has no write
+# access to that.
+# It works when running as normal root with unrestricted capabilities
+# because then CAP_MAC_OVERRIDE (a Smack-specific capability) allows
+# the process to ignore Smack rules.
+# We need to ensure that bluetoothd still has that capability.
+# To fix the issue, Patick and Casey(the Smack architect) had a talk
+# about it in Ostro dev mail list. Casey has some ideas about the issue:
+# "Turning off privilege is a great thing to do *so long as you don't
+# really need the privilege*. In this case you really need it.
+# The application package isn't written to account for Smack's use of
+# CAP_MAC_OVERRIDE as the mechanism for controlling this dangerous operation.
+# Yes, it would be possible to change /proc to change the Smack label on
+# that particular file, but that might open other paths for exploit.
+# I say give the program the required capability. The program maintainer
+# may well say change the kernel handling of /proc. You're stuck in the
+# middle, as both work the way they're intended and hence the system
+# doesn't work. :( There isn't a way to make this work without "loosening"
+# something."
+# Therefore, when we we run the program with CAP_MAC_OVERRIDE,
+# the whole reason for having capabilities is so the we can give a
+# process the ability to bypass one kind of check without giving it the
+# ability to bypass other, unrelated checks. A process with
+# CAP_MAC_OVERRIDE is still constrained by the file mode bits.
+# We was overly worried about granting that capability.
+# When it has no other effect than excluding a process from Smack MAC enforcement,
+# then adding to the process seems like the right solution for now.
+# The conclusion from Patick and Casey is that the Smack architect give the key point
+# that this is the solution preferred.
+# Because the solution is to some extend specific to the environment
+# in which connmand runs, this change is not submitted upstream
+# and it can be overridden by a distro via FIX_BLUEZ5_CAPABILITIES.
+# The related patch has been submitted to upstream too.
+# upstream link:
+FIX_BLUEZ5_CAPABILITIES_with-lsm-smack ??= "fix_bluez5_capabilities"
+do_install[postfuncs] += "${FIX_BLUEZ5_CAPABILITIES}"
+fix_bluez5_capabilities () {
+ service="${D}/${systemd_unitdir}/system/bluetooth.service"
+ if [ -f "$service" ] &&
+ grep -q '^CapabilityBoundingSet=' "$service"; then
+ sed -i -e 's/^CapabilityBoundingSet=/CapabilityBoundingSet=CAP_MAC_OVERRIDE /' "$service"
+ fi