Android Capability Fine-grained permissions control

1. Traditional Uid/gid, the granularity of permission is too large

2. Capability: Fine-grained permission control

3. Capability of the process

4. Capability of documents

5. Capability Boundset of the process

6. Capability of the Spawn process

7. Compatibility of capability and UID

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1. Traditional Uid/gid, the granularity of permission is too large

Permission particles are too coarse

Prone to excessive entitlement (overflow), giving too much authority

Security issues caused by overflow/excess: Too many permissions

Resolution: We need fine-grained permissions: In addition to the emperor, different magistrates are needed.

Linux introduces Capabilit: Each capability system is represented by a bit,

More than 30 capability are currently defined, but the OS uses 64bit storage internally for future expansion

2. Capability: Fine-grained permission control

Android capability files: android_filesystem_capability.h

Define Cap_chown 0, representing the No. 0 bit in the 64 bit

3. Capability of the process

4. Capability of documents

5. Capability Boundset of the process

6. Capability of the Spawn process

7. Compatibility of capability and UID

Android Capability Fine-grained permissions control