I am using Ubuntu 14.04, and I want to create a virtual machine running OS X. I have a friend who owns an iMac with OS X Yosemite. Is there any way to create an ISO without downloading an installer? Or is there any way to download a legit ISO from my computer?
You can't create an installer iso from an installed OS X system (without OS X Yosemite installer downloaded).
Aside from the legality of your intention you can clone the disk of the iMac though and move the final vdi file to your host system, if you don't want to create an installer image:
Boot to another boot volume with a full system on a different disk (e.g. a USB thumb drive). VirtualBox has to be installed. You need a third drive with enough free space to save the disk image.
Open Terminal and enter:
to get the device node of the main disk (probably /dev/disk0).
Unmount the disk with:
diskutil umountDisk /dev/disk0
Clone the main disk with:
sudo VBoxManage convertfromraw /dev/disk0 /Volumes/Path/to/OSX.vdi --format VDI
This will create a dynamic disc containing all volumes (EFI/Recovery HD/main disk etc.) with roughly the size of the occupied blocks of the disk: unallocated disk space or free volume space won't be copied!
Change the ownership of the file:
sudo chown user:group /Volumes/Path/to/OSX.vdi
Copy/move the file to your host.
Now open VirtualBox and create a new VM -> OS X 10.10 and configure it. Choose the file OSX.vdi as main hard disk. To get the VM working you may have to choose a different chipset: PIIX3 instead of the default ICH9. You may also have to change the CPUID with:
# get the name of the OS X VM VBoxManage list vms # change the CPUID of the OS X Yosemite VM (here the name is OSX) VBoxManage modifyvm OSX --cpuidset 00000001 000306a9 00020800 80000201 178bfbff
Now boot the VM and create a new admin and remove all other users or unwanted apps.
However, I still recommend to create a dmg image using the OS X Yosemite installer and install it from scratch.
Is there any way to create an ISO without downloading an installer?
There is no way to create an ISO without downloading the installer. The next logical question is Can you download a premade ISO? The answer to that is yes but you won't be getting it from Apple. I am not saying you can't get it from a torrent or some other site, what I am saying is that it is one of the most risky thing you can do - to download an unauthorized installation ISO of OS X.
is there any way to download a legit ISO from my computer?
No for two reasons. One, you can't download an ISO; you can download the installer and create an ISO. Two, you can't download the installer on anything but OS X.