GalaxyS3I9300PrivacySecurityEvaluation » History » Version 29
Denis 'GNUtoo' Carikli, 09/06/2020 11:44 PM
Fix mistakes with the modem flight mode and add more infos on it.
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Note that this information may or may not be exhaustive.
It also may or may not contain all known issues or good point about this device.
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h2. General freedom issues on the Galaxy S 3 (I9300):
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* The bootloader is proprietary and signed. It's only possible to replace part of it.
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* The bootloader also loads a proprietary OS on the main CPU, in "TrustZone":https://en.wikipedia.org/wiki/Trusted_execution_environment. See "this analysis":https://sensepost.com/blog/2013/a-software-level-analysis-of-trustzone-os-and-trustlets-in-samsung-galaxy-phone/ for more details on the precise implementation for the Galaxy SIII.
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* Some peripherals do require proprietary firmwares to work.
** See [[GalaxyS3I9300LoadedFirmwares|some of which have to be loaded by the system]].
** See also the "Missing without non-free firmwares" status in [[ReplicantStatus]].
* The bootrom is the first code that is executed, it's stored in a read-only memory: see "freedom-privacy-security-issues":https://www.replicant.us/freedom-privacy-security-issues.php for more details.
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* The hardware is proprietary, and we are not aware if any complete schematics is available somewhere on the Internet.
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h2. Modem related:
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The modem runs non-free software, which is loaded but not shipped by Replicant.
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* When using flight mode, The main CPU has to ask the modem to put itself in low power mode (and not transmit anymore).
** When booting Replicant 6 in flight mode, the modem still communicates with the SIM card.
** When booting Replicant 6 with the modem disabled (modem.sh off) either in flight modem or without being in flight mode, no access to the SIM card is done.
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* The modem is isolated:
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** It doesn't use shared memory to communicate with the main CPU, instead it uses HSIC, which is a version of USB 2.0 meant to interface chips together directly. Here the modem also cannot change USB IDs without having the main CPU reset the HSIC bus.
** We are not aware of it being able to access the GPS, but it wouldn't be surprising if it still could (by having a direct connection to it: since no schematics are publicly available we have easy no way to check).
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** It has no access to the other CPU peripherals.
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* "Terminal profile":https://terminal-profile.osmocom.org/decode.php?tp=ffffffff7f1f00dfff00001fa2010a860749000000000000000000000010
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* Investigate its terminal profile
* Investigate device factory reset security in both Replicant and its recovery (Does it really wipe files?)
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* Investigate the flash layout, EMMC partitions, EMMC firmware
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* The Exynos 4412 reference manual says that the PMIC firmware can be reflashed (see the IROM_DATA_REG0 register in the subsection 22.214.171.124 of the Chapter 8 (Power Management Unit)).