84b96a6b68
HALs are intended to be limited responsibility and thus limited
permission. In order to enforce this, place limitations on:
1. What processes may transition into a HAL - currently only init
2. What methods may be used to transition into a HAL - no using
seclabel
3. When HALs exec - only allow exec with a domain transition.
Bug: 36376258
Test: Build aosp_marlin, aosp_bullhead, aosp_dragon. Neverallow rules
are compile time assertions, so building is a sufficient test.
Change-Id: If4df19ced730324cf1079f7a86ceba7c71374131
52 lines
1.9 KiB
Text
52 lines
1.9 KiB
Text
# only HALs responsible for network hardware should have privileged
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# network capabilities
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neverallow {
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halserverdomain
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-hal_bluetooth_server
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-hal_wifi_server
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-hal_wifi_supplicant_server
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-rild
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} self:capability { net_admin net_raw };
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# Unless a HAL's job is to manage network hardware, it should not be
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# using network sockets.
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neverallow {
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halserverdomain
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-hal_gnss # TODO b/36085168 b/35757613
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-hal_wifi_server
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-hal_wifi_supplicant_server
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-rild
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} domain:{ tcp_socket udp_socket rawip_socket } *;
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###
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# HALs are defined as an attribute and so a given domain could hypothetically
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# have multiple HALs in it (or even all of them) with the subsequent policy of
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# the domain comprised of the union of all the HALs.
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#
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# This is a problem because
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# 1) Security sensitive components should only be accessed by specific HALs.
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# 2) hwbinder_call and the restrictions it provides cannot be reasoned about in
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# the platform.
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# 3) The platform cannot reason about defense in depth if there are
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# monolithic domains etc.
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#
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# As an example, hal_keymaster and hal_gatekeeper can access the TEE and while
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# its OK for them to share a process its not OK with them to share processes
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# with other hals.
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#
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# The following neverallow rules, in conjuntion with CTS tests, assert that
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# these security principles are adhered to.
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#
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# Do not allow a hal to exec another process without a domain transition.
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# TODO remove exemptions.
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neverallow {
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halserverdomain
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-hal_dumpstate_server
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-rild
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} { file_type fs_type }:file execute_no_trans;
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# Do not allow a process other than init to transition into a HAL domain.
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neverallow { domain -init } halserverdomain:process transition;
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# Only allow transitioning to a domain by running its executable. Do not
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# allow transitioning into a HAL domain by use of seclabel in an
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# init.*.rc script.
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neverallow * halserverdomain:process dyntransition;
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