The kernel is at the heart of the security of any operating system. By choosing Linux, which has evolved as a trusted platform over the years, Android has established a very solid security foundation. Most of the security features that are inherent to the Linux kernel are automatically adopted by Android. For example, the user-based permission model of Linux has, in fact, worked well for Android. As mentioned earlier, there is a lot of specific code built into the Linux kernel. With each Android version release, the kernel version has also changed. The following table shows Android versions and their corresponding kernel versions:
|
Android version |
Linux kernel version |
|
1 |
2.6.25 |
|
1.5 |
2.6.27 |
|
1.6 |
2.6.29 |
|
2.2 |
2.6.32 |
|
2.3 |
2.6.35 |
|
3.0 |
2.6.36 |
|
4.0 |
3.0.1 |
|
4.1 |
3.0.31 |
|
4.2 |
3.4.0 |
|
4.2 |
3.4.39 |
|
4.4 |
3.8 |
|
5.0 |
3.16.1 |
|
6.0 |
3.18.1 |
|
7.0 |
4.4.1 |
|
8.0 |
4.10 |
|
9.0 |
4.4, 4.9, and 4.14 |
|
10.0 |
4.9, 4.14, and 4.19 |
The Linux kernel automatically brings some of its inherent security features, such as the following, to the Android platform:
- A user-based permissions model
- Isolation of running processes (application sandbox)
- Secure inter-process communication (IPC)
We shall now learn about each of these features.