netbsd.md: Changes made in file about missing clarity (google#535)

* Changes made in the netbsd.md file, syzkaller made easier to install

* Name added to list of contributors

* Added name to CONTRIBUTORS file

* Changes in file regarding format issues

Author: SUMUKHA-PK

AUTHORS

@@ -17,3 +17,4 @@ Utkarsh Anand
 Tobias Klauser
 Tim Tianyang Chen
 Ed Maste
+Sumukha PK

CONTRIBUTORS

@@ -28,3 +28,4 @@ Utkarsh Anand
 Tobias Klauser
 Tim Tianyang Chen
 Ed Maste
+Sumukha PK

docs/netbsd.md

@@ -2,49 +2,80 @@
 
 ## How to run syzkaller on NetBSD using qemu
 
-So far the process is tested only on linux/amd64 host. To build Go binaries do:
+
+1. Steps to set up NetBSD on qemu: 
+	* To create a .img file where the OS is stored: ( Here 30G indicates the size of .img file as 30gb. Anything above 10gb is fine)
+```  qemu-img create -f raw NetBSD.img 30G
+```
+	* To install the .iso file in the .img: (Here NetBSD-7.0.2-amd64.iso is the iso file and NetBSD.img is the img file created in the first step)
+```
+	 qemu-system-x86_64 -hda NetBSD.img -cdrom NetBSD-7.0.2-amd64.iso 
+```
+	* To boot up every time to the .img file:  (Have to be in the same directory as the .img file)
+```
+	 qemu-system-x86_64 -hda NetBSD.img -redir tcp:10022::22
+```
+Here the -redir flag is redirecting the 10022 on host to 22 port on guest.
+
+2. So far the process is tested only on linux/amd64 host. To build Go binaries do:
 ```
 make TARGETOS=netbsd
 ```
-To build C `syz-executor` binary, copy `executor/*` files to a NetBSD machine and build there with:
+
+3. To build C `syz-executor` binary, copy `executor/*` files to a NetBSD machine and build there with:
 ```
 gcc executor/executor_NetBSD.cc -o syz-executor -O1 -lpthread -DGOOS=\"netbsd\" -DGIT_REVISION=\"CURRENT_GIT_REVISION\"
 ```
-Then, copy out the binary back to host into `bin/netbsd_amd64` dir.
+
+"scp host@ip:/directory-of-source /directory-of-destination" command can be used to copy the files from the host to the guest.
+
+4. Then, copy out the binary back to host into `bin/netbsd_amd64` dir.(Inside the syzkaller directory)
 
 Building/running on a NetBSD host should work as well, but currently our `Makefile` does not work there, so you will need to do its work manually.
 
-Then, you need a NetBSD image with root ssh access with a key. General instructions can be found here [qemu instructions](https://wiki.qemu.org/Hosts/BSD).
+(Anita steps are optional if the NetBSD OS is  up and running, which it already is..)
+
+5. Then, you need a NetBSD image with root ssh access with a key. General instructions can be found here [qemu instructions](https://wiki.qemu.org/Hosts/BSD).
 
-To prepare the image, use `anita`. (You need the python module `pexpect` installed, for using Anita)
+6. To prepare the image, use `anita`. (You need the python module `pexpect` installed, for using Anita)
 ```
 git clone https://github.com/utkarsh009/anita
 python anita/anita --workdir anitatemp install http://nycdn.netbsd.org/pub/NetBSD-daily/netbsd-8/201710221410Z/amd64/
 ```
 NOTE: You can choose your own release tree from here: http://ftp.netbsd.org/pub/NetBSD/
 URL for a daily build might not exist in future and new release trees keep coming out.
 
-Then spin up an instance from the image generated inside `./anitatemp` directory
+7. Then spin up an instance from the image generated inside `./anitatemp` directory
 ```
 qemu-system-x86_64 -m 1024 -drive file=anitatemp/wd0.img,format=raw,media=disk -netdev user,id=mynet0,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10022-:22 -device e1000,netdev=mynet0 -nographic
 ```
-Then create an ssh-keypair without a password and save it by the name, say, `netbsdkey`
 
+8. Then create an ssh-keypair without a password and save it by the name, say, `netbsdkey`
+
+(This is done in the host OS until specified otherwise)
 ```
 ssh-keygen -t rsa
 ```
-Then append the following to `/etc/rc.conf`
+
+(This is done in the Guest OS until specified otherwise)
+
+9. Then append the following to `/etc/rc.conf`
 ```
 sshd=YES
 ifconfig_wm0="inet 10.0.2.15 netmask 255.255.255.0"
 ```
-Append this to `/etc/ssh/sshd_config`
+
+10. Append this to `/etc/ssh/sshd_config`
 ```
 Port 22
 ListenAddress 10.0.2.15
 ```
-Then add your pubkey to `/root/.ssh/authorized_keys` and `reboot` the VM.
-When you see the login prompt, open up another terminal on host and issue the following command
+
+11. Then add your pubkey to `/root/.ssh/authorized_keys` and `reboot` the VM.
+
+(Switch to host)
+
+12. When you see the login prompt, open up another terminal on host and issue the following command
 ```
 ssh -i netbsdkey -p 10022 [email protected]
 ```
@@ -70,11 +101,15 @@ If all of the above worked, `poweroff` the VM and create `netbsd.cfg` config fil
 	}
 }
 ```
+(Above directories have to be specified to the exact locations and the ssh keys must be in a separate directory with chmod 700 permissions set to that directory and chmod 600 permissions to the files in both the guest and the host.)
+
 
-Then, start `syz-manager` with:
+13. Then, start `syz-manager` with: (Inside the syzkaller folder where the netbsd.cfg file also exists)
 ```
 bin/syz-manager -config netbsd.cfg
 ```
+Also, append ```PermitRootLogin without-password``` to .ssh/sshd_config in guest.
+
 It should start printing output along the lines of:
 ```
 booting test machines...
@@ -85,7 +120,8 @@ executed 7921, cover 1239, crashes 0, repro 0
 executed 32807, cover 1244, crashes 0, repro 0
 executed 35803, cover 1248, crashes 0, repro 0
 ```
-If something does not work, add `-debug` flag to `syz-manager`.
+
+14. If something does not work, add `-debug` flag to `syz-manager`.
 
 ## Missing things