Create a host side parser for init such that init rc files can be
verified for syntax correctness before being used on the device.
Bug: 36970783
Test: run the parser on init files on host
Change-Id: I7e8772e278ebaff727057308596ebacf28b6fdda
This change explicitly drops all inheritable capabilities (and, by
extension, ambient capabilities) when there are no explicit capabilities
being set by a service and the user is changed. This prevents Android
running in a container from accidentally granting extra capabilities to
services.
Bug: 69320306
Test: aosp_sailfish still boots
Test: sailfish:/ $ grep Cap /proc/`pidof android.hardware.audio@2.0-service`/status
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 0000003fffffffff
CapAmb: 0000000000000000
Test: sailfish:/ $ grep Cap /proc/`pidof logd`/status
CapInh: 0000000000000000
CapPrm: 0000000440000000
CapEff: 0000000440000000
CapBnd: 0000003fffffffff
CapAmb: 0000000000000000
Test: Android in Chrome OS still boots
Test: localhost ~ # grep Cap /proc/`pidof android.hardware.audio@2.0-service`/status
CapInh: 0000000000000000
CapPrm: 0000000000000000
CapEff: 0000000000000000
CapBnd: 000000006daefdff
CapAmb: 0000000000000000
Test: localhost ~ # grep Cap /proc/`pidof logd`/status
CapInh: 0000000000000000
CapPrm: 0000000040000000
CapEff: 0000000040000000
CapBnd: 000000006daefdff
CapAmb: 0000000000000000
Change-Id: I9218f2e27ff4fb4d91d50f9a98c0fdb4e272952c
This change homogenizes the use of std::unique_ptr for storing
capabilities in system/core/.
Bug: None
Test: m
Change-Id: I0a95f87a27b0261e9d321841d5140fc000473293
Partners have expressed interest in using the 'capabilities' keyword
in init, so make the code more resilient:
-Check that ambient capabilities are supported by the kernel.
-Check that the last valid cap at runtime is not higher than what's in
kernel headers.
-Check that the user is not requesting a capability present in kernel
headers but not supported by the kernel at runtime.
-Don't attempt to drop bounding set capabilities not supported at
runtime.
This CL also fixes a small bug where < should have been used instead of
<=, and uses 'static' instead of anonymous namespaces.
Bug: 32438163
Test: Use a test service that uses capabilities.
Test: Apply in internal tree and test with angler and rild.
Change-Id: Ia271cc7eb389d1d526d61f897261e4bac4d19e5d
Ambient capabilities are inherited in a straightforward way across
execve(2):
"
If you are nonroot but you have a capability, you can add it to pA.
If you do so, your children get that capability in pA, pP, and pE.
For example, you can set pA = CAP_NET_BIND_SERVICE, and your
children can automatically bind low-numbered ports.
"
This will allow us to get rid of the special meaning for AID_NET_ADMIN
and AID_NET_RAW, and if desired, to reduce the use of file capabilities
(which grant capabilities to any process that can execute the file). An
additional benefit of the latter is that a single .rc file can specify
all properties for a service, without having to rely on a separate file
for file capabilities.
Ambient capabilities are supported starting with kernel 4.3 and have
been backported to all Android common kernels back to 3.10.
I chose to not use Minijail here (though I'm still using libcap) for
two reasons:
1-The Minijail code is designed to work in situations where the process
is holding any set of capabilities, so it's more complex. The situation
when forking from init allows for simpler code.
2-The way Minijail is structured right now, we would not be able to
make the required SELinux calls between UID/GID dropping and other priv
dropping code. In the future, it will make sense to add some sort of
"hook" to Minijail so that it can be used in situations where we want
to do other operations between some of the privilege-dropping
operations carried out by Minijail.
Bug: 32438163
Test: Use sample service.
Change-Id: I3226cc95769d1beacbae619cb6c6e6a5425890fb
