no longer possible to retrieve SD card serial number, as of Nougat [37705442]

Infeasible

Bug

Status Update

No update yet.

Description

hu...@gmail.com

created issue #1

Apr 26, 2017 03:57PM

Steps to reproduce, and the output I expected (which is what happens on Android devices pre-7.0, e.g. on an LG-K371 Android 6.0):

- Mount an SD card in a built-in (not USB-connected) SD card slot in an Android device.
$ adb shell
shell@m1v:/ $ ls /sys/class/mmc_host
mmc0
mmc1
shell@m1v:/ $ ls -d /sys/class/mmc_host/mmc*/mmc*
/sys/class/mmc_host/mmc0/mmc0:0001
/sys/class/mmc_host/mmc1/mmc1:0007
shell@m1v:/ $ cat /sys/class/mmc_host/mmc0/mmc0\:0001/type
MMC
shell@m1v:/ $ cat /sys/class/mmc_host/mmc1/mmc1\:0007/type
SD
shell@m1v:/ $ cat /sys/class/mmc_host/mmc1/mmc1\:0007/serial
0x01b71112
shell@m1v:/ $ cat /sys/class/mmc_host/mmc1/mmc1\:0007/cid
27504853443847423001b71112010900
shell@m1v:/ $ cat /sys/class/mmc_host/mmc1/mmc1\:0007/csd
400e00325b59000039b37f800a400000
shell@m1v:/ $ cat /sys/class/mmc_host/mmc1/mmc1\:0007/name
SD8GB

The "type" file allows us to determine which mmc device is an (external) SD card, and which is an (internal) MMC.
The "serial" and other files give us the serial number, CID, name, etc. of the chip.

Problem behavior on Android 7.0 device (Alcatel A30 GSM / 5046G):

$ adb shell
MICKEY6US:/ $ ls /sys/class/mmc_host
ls: /sys/class/mmc_host/mmc0: Permission denied
ls: /sys/class/mmc_host/mmc1: Permission denied
1|MICKEY6US:/ $ ls -d /sys/class/mmc_host/mmc*/mmc*
/sys/class/mmc_host/mmc0/mmc0:0001
127|MICKEY6US:/ $ cat /sys/class/mmc_host/mmc0/mmc0\:0001/type
/system/bin/sh: cat: /sys/class/mmc_host/mmc0/mmc0:0001/type: Permission denied
1|MICKEY6US:/ $ cat /sys/class/mmc_host/mmc0/mmc0\:0001/serial
/system/bin/sh: cat: /sys/class/mmc_host/mmc0/mmc0:0001/serial: Permission denied
1|MICKEY6US:/ $ cat /sys/class/mmc_host/mmc0/mmc0\:0001/cid
/system/bin/sh: cat: /sys/class/mmc_host/mmc0/mmc0:0001/cid: Permission denied
1|MICKEY6US:/ $ cat /sys/class/mmc_host/mmc0/mmc0\:0001/csd
/system/bin/sh: cat: /sys/class/mmc_host/mmc0/mmc0:0001/csd: Permission denied
1|MICKEY6US:/ $ cat /sys/class/mmc_host/mmc0/mmc0\:0001/name
/system/bin/sh: cat: /sys/class/mmc_host/mmc0/mmc0:0001/name: Permission denied

Why it matters: Publishers of rights-protected content often use a DRM scheme that is keyed off the serial number of the SD card. Until now, such content could be played on Android devices because they could read the SD card's serial number. As of Android 7, it appears this will no longer be possible. As such, publishers, app developers and users are motivated to stay with older versions of Android, or lose access to rich content.

Another report of the (probably the same) issue (

https://www.humanlogic.com/sdinsight/#faq) "***COMPATIBILITY NOTICE***: It has come to our attention that SD Insight is not compatible with some Android 7.0+ handsets. Google recently made a change in Android 7 that blocks SD Insight and other apps that use the same API. This change seems to have been only implemented by some phone manufacturers and not others. We do not know of a workaround at this time."

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Comments

hu...@gmail.com <hu...@gmail.com> #2Apr 26, 2017 04:16PM

+1
I am interested in this feature as well for Master/Detail.

ma...@gmail.com <ma...@gmail.com> #3Apr 26, 2017 08:52PM

Another use case is that if you have a full page spinner activity that loads data from the network.
Once the data is loaded the app navigates to a 2nd activity that presents the data.

We would like to be able to use the same ViewModel instance in both activities.

hu...@gmail.com <hu...@gmail.com> #4Apr 26, 2017 09:45PM

Adding a situation which I need this: I don't want the UI to wait for a network call. Showing a detail activity will need to get the detail data from the server.

So if I start the API call (which is of course done by the ViewModel) as soon as the user clicks the item, it is already fetching the data while transitioning to the second screen.
Then I don't have to block the starting of the detail activity or wait to trigger the API call until the detail activity is started

ar...@google.com <ar...@google.com> #5Apr 27, 2017 01:23PM

Status: Won't Fix (Infeasible)

@ #4

My solution for share data between multi activities:

https://github.com/googlesamples/android-architecture-components/issues/29#issuecomment-407291032

hu...@gmail.com <hu...@gmail.com> #6Apr 27, 2017 03:34PM

what is the status of this issue ??

ma...@gmail.com <ma...@gmail.com> #7Apr 27, 2017 03:48PM

does any work has done regrading this ??

[Deleted User] <[Deleted User]> #8Aug 23, 2017 11:50AM

we need fatures share the viewModel between activites to apply ViewModel with old project without restructure the app from zero

hu...@gmail.com <hu...@gmail.com> #9Aug 23, 2017 02:20PM

Please add this feature, unfortunately this request has been ignored for 3 years

ye...@gmail.com <ye...@gmail.com> #10Feb 26, 2023 04:15PM

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