107 lines
3.2 KiB
Text
107 lines
3.2 KiB
Text
# gsid - Manager for GSI Installation
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type gsid, domain;
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type gsid_exec, exec_type, file_type, system_file_type;
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typeattribute gsid coredomain;
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init_daemon_domain(gsid)
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binder_use(gsid)
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binder_service(gsid)
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add_service(gsid, gsi_service)
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# Needed to create/delete device-mapper nodes, and read/write to them.
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allow gsid dm_device:chr_file rw_file_perms;
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allow gsid dm_device:blk_file rw_file_perms;
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allow gsid self:global_capability_class_set sys_admin;
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dontaudit gsid self:global_capability_class_set dac_override;
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# libfiemap_writer uses sysfs to derive the bottom of a device-mapper stacking.
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# This requires traversing /sys/block/dm-N/slaves/* and reading the list of
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# file names.
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allow gsid sysfs_dm:dir r_dir_perms;
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# Needed to stat /data/gsi/* and realpath on /dev/block/by-name/*
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allow gsid block_device:dir r_dir_perms;
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# liblp queries these block alignment properties.
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allowxperm gsid userdata_block_device:blk_file ioctl {
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BLKIOMIN
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BLKALIGNOFF
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};
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# gsi_tool passes the system image over the adb connection, via stdin.
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allow gsid adbd:fd use;
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# gsid needs to store images on /data, but cannot use file I/O. If it did, the
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# underlying blocks would be encrypted, and we couldn't mount the GSI image in
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# first-stage init. So instead of directly writing to /data, we:
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#
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# 1. fallocate a file large enough to hold the signed GSI
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# 2. extract its block layout with FIEMAP
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# 3. create a dm-linear device using the FIEMAP, targeting /dev/block/by-name/userdata
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# 4. write system_gsi into that dm device
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#
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# To make this process work, we need to unwrap the device-mapper stacking for
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# userdata to reach the underlying block device. To verify the result we use
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# stat(), which requires read access.
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allow gsid userdata_block_device:blk_file r_file_perms;
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# gsid uses /metadata/gsi to communicate GSI boot information to first-stage
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# init. It cannot use userdata since data cannot be decrypted during this
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# stage.
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#
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# gsid uses /metadata/gsi to store three files:
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# install_status - A short string indicating whether a GSI image is bootable.
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# lp_metadata - LpMetadata blob describing the block ranges on userdata
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# where system_gsi resides.
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# booted - An empty file that, if exists, indicates that a GSI is
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# currently running.
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#
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allow gsid metadata_file:dir search;
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allow gsid gsi_metadata_file:dir rw_dir_perms;
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allow gsid gsi_metadata_file:file create_file_perms;
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allow gsid gsi_data_file:dir rw_dir_perms;
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allow gsid gsi_data_file:file create_file_perms;
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allowxperm gsid gsi_data_file:file ioctl FS_IOC_FIEMAP;
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neverallow {
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domain
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-init
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-gsid
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-fastbootd
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-vold
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} gsi_metadata_file:dir *;
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neverallow {
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domain
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-init
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-gsid
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-fastbootd
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-vold
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} gsi_metadata_file:notdevfile_class_set ~{ relabelto getattr };
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neverallow {
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domain
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-init
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-gsid
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-fastbootd
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-vold
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} { gsi_data_file gsi_metadata_file }:notdevfile_class_set *;
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neverallow {
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domain
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-gsid
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} gsi_data_file:dir ~{ open create read getattr setattr search relabelto ioctl };
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neverallow {
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domain
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-init
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-gsid
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} gsi_data_file:dir *;
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neverallow {
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domain
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-gsid
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} gsi_data_file:notdevfile_class_set ~{ relabelto getattr };
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