Prevent kernel version earlier than 3.3

Kernels earlier than 3.3.x have many bugs.

The following are just examples of those:
 - Some kernels need exactly ext3 fs to boot
 - Some kernels has errors from glibc, need patch. "getline error",
 - Current Debian stable does not support kernels before 3.2
 - Error from m4 package, need patch. "freadahead.c error"
 - Error from ttyS0 at boot
 - Some kernels get stuck at "booting kernel"
 - Some kernels get stuck elsewhere
 - Network might fail even it has been tested working for later kernels
 - Package "inet" might fail at boot. "if_index.os error"

exploitdb/ctfsetup/qemu/Readme.md

@@ -18,7 +18,7 @@ Supported CPU architectures:
  - x86_64 (see Limitations)
 
 Supported Linux kernels:
- - 3.x (>3.2)
+ - 3.x (>3.3)
  - 4.x
  - 5.x
 
@@ -31,12 +31,10 @@ Default config options we use for Buildroot:
 |----------------|----------------|----------------------------|
 | arch           | i386           | Supports older kernels     |
 | defconfig name | i386           | Matches arch               |
-| kernel version | <_latest_>     | Will prompt user           |
+| kernel version | 3.18.100       | Will prompt user           |
 | kernel header  | Same as kernel | Will in theory always work |
-| C++ support    | y              | Required for IPv6 support  |
 | gcc version    | <_depends on kernel_> | Latest gcc which the kernel supports |
 
-The user will get an option to modify these options manually.
 
 Debian image setup additionally enables the following features:
  - OpenSSL
@@ -45,6 +43,16 @@ Debian image setup additionally enables the following features:
  - Eth0 network
 
 
+### Useful commands
+
+List all running Qemu VM processes:
+
+    ps aux | grep qemu
+
+Kill all running Qemu VM processes:
+
+    pkill -f qemu -9
+
 ### Project structure:
 
     qemu
@@ -108,7 +116,7 @@ Debian image setup additionally enables the following features:
 
  - No way to detect a crashed qemu vm. A simple "ssh port is open" check on qemu booting is implemented,
    but it is unreliable as a kernel could still have crashed even if the port is open.
- - Kernels before 3.2.x are not supported. System will try running it, and sometimes it boots, 
+ - Kernels before 3.3.x are not supported. System will try running it, and sometimes it boots, 
    sometimes doesn't. There are many compatibility issues on the old kernels mostly because of `glibc` updates.
  - I have been trying out different package patches on glibc.
    Some luck was shown, but the fixes were not consistent, as moving to a slightly older kernel 
@@ -119,7 +127,7 @@ Debian image setup additionally enables the following features:
  - Only Debian OS are supported.
  
  - The earliest Buildroot release is from 2012. The program do not necessarily support
-   compiling kernels earlier than 3.2. 
+   compiling kernels earlier than 3.3. 
   
  - Different steps of the program is not run in parallel. Running Debian image setup and kernel compilation
    simultaneously is not supported yet.

exploitdb/ctfsetup/qemu/buildroot_setup.py

@@ -67,7 +67,8 @@ def validate_buildroot_version(kwargs: dict):
     year = datetime.datetime.now().year
 
     # At year 2014, Buildroot had another menuconfig interface.
-    # buildroot version before 2015 is not supported
+    # buildroot version before 2019 is not supported
+    # TODO: Add support by including a collection of patches to solve different errors of old versions
     while year > 2018:
         # Buildroot before 2017 is not supported by kconfiglib, as it cannot correctly parse the config files
         #    package/libcrossguid/Config.in:15 error: couldn't parse [...]

exploitdb/ctfsetup/qemu/setup.py

@@ -68,9 +68,16 @@ def setup(**kwargs):
     verbose_log("Using working dir:", os.getcwd())
 
     log("Validating and fixing input kwargs")
-
     kwargs = derive_input_kwargs(**kwargs)
 
+    # Kernel versions earlier than 3.2 is not supported yet.
+    # TODO: Implement proper fix
+    kernel_version = kwargs['kernel_version'].split('.')
+    kernel_version_compare_num = int(kernel_version[0])*100 + int(kernel_version[1])
+    if kernel_version_compare_num < 303:
+        print("Kernel version earlier than 3.3 is not supported")
+        exit()
+
     log("Creating a Qemu VM by these parameters:")
     log("   Architecture:   ", kwargs['arch'])
     log("   Kernel version: ", kwargs['kernel_version'])