1 files changed, 32 insertions, 0 deletions
diff --git a/meta-security/recipes-connectivity/connman/connman_%.bbappend b/meta-security/recipes-connectivity/connman/connman_%.bbappend
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index 000000000..f66c1e79b
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+++ b/meta-security/recipes-connectivity/connman/connman_%.bbappend
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+# Recent ConnMan releases started limiting the capabilities of
+# ConnMan. When running on a Smack-enabled system, that change has the
+# effect that connmand can no longer change network settings under
+# /proc/net because the Smack label of /proc is "_", and connmand
+# 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 connmand still has that capability.
+#
+# The alternative would be to set up fine-grained labelling of
+# /proc with corresponding rules, which is considerably more work
+# and also may depend on kernel changes (like supporting smackfsroot
+# for procfs, which seems to be missing at the moment).
+#
+# 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_CONNMAN_CAPABILITIES.
+
+FIX_CONNMAN_CAPABILITIES ??= ""
+FIX_CONNMAN_CAPABILITIES_with-lsm-smack ??= "fix_connman_capabilities"
+do_install[postfuncs] += "${FIX_CONNMAN_CAPABILITIES}"
+
+fix_connman_capabilities () {
+    service="${D}/${systemd_unitdir}/system/connman.service"
+    if [ -f "$service" ] &&
+        grep -q '^CapabilityBoundingSet=' "$service"; then
+        sed -i -e 's/^CapabilityBoundingSet=/CapabilityBoundingSet=CAP_MAC_OVERRIDE /' "$service"
+    fi
+}