d329e7ebc9
Mediaextractor should only be operating on data passed directly to it. It shouldn't be attempting to open /data files on it's own. Add a neverallow statement (compile time assertion + CTS test) to ensure this is the case. Bug: 67454004 Test: policy compiles. No runtime impact. Change-Id: Ie94d4cb9aece7e72fbd13321f339dcf9d44d5d77
63 lines
2.3 KiB
Text
63 lines
2.3 KiB
Text
# mediaextractor - multimedia daemon
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type mediaextractor, domain;
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type mediaextractor_exec, exec_type, file_type;
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typeattribute mediaextractor mlstrustedsubject;
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binder_use(mediaextractor)
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binder_call(mediaextractor, binderservicedomain)
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binder_call(mediaextractor, appdomain)
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binder_service(mediaextractor)
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add_service(mediaextractor, mediaextractor_service)
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allow mediaextractor mediametrics_service:service_manager find;
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allow mediaextractor hidl_token_hwservice:hwservice_manager find;
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allow mediaextractor system_server:fd use;
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hal_client_domain(mediaextractor, hal_cas)
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r_dir_file(mediaextractor, cgroup)
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allow mediaextractor proc_meminfo:file r_file_perms;
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crash_dump_fallback(mediaextractor)
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# Suppress denials from sdcardfs (b/67454004)
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dontaudit mediaextractor sdcardfs:file read;
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# allow mediaextractor read permissions for file sources
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allow mediaextractor media_rw_data_file:file { getattr read };
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allow mediaextractor app_data_file:file { getattr read };
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# Read resources from open apk files passed over Binder
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allow mediaextractor apk_data_file:file { read getattr };
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allow mediaextractor asec_apk_file:file { read getattr };
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allow mediaextractor ringtone_file:file { read getattr };
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###
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### neverallow rules
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###
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# mediaextractor should never execute any executable without a
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# domain transition
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neverallow mediaextractor { file_type fs_type }:file execute_no_trans;
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# The goal of the mediaserver split is to place media processing code into
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# restrictive sandboxes with limited responsibilities and thus limited
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# permissions. Example: Audioserver is only responsible for controlling audio
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# hardware and processing audio content. Cameraserver does the same for camera
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# hardware/content. Etc.
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#
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# Media processing code is inherently risky and thus should have limited
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# permissions and be isolated from the rest of the system and network.
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# Lengthier explanation here:
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# https://android-developers.googleblog.com/2016/05/hardening-media-stack.html
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neverallow mediaextractor domain:{ tcp_socket udp_socket rawip_socket } *;
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# mediaextractor should not be opening /data files directly. Any files
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# it touches (with a few exceptions) need to be passed to it via a file
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# descriptor opened outside the process.
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neverallow mediaextractor {
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data_file_type
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-zoneinfo_data_file # time zone data from /data/misc/zoneinfo
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}:file open;
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