Did Linux Mint leak into Windows in my dual drive-dual boot setup?

[Luxzio22]

I have a dual drive, dual boot setup installed like the one described here (plays at the correct time): https://youtu.be/KWVte9WGxGE?si=SOfRDuPsi6Wy5aFa&t=447

Basically I have Windows 10 installed on a 1TB HDD and I installed Linux Mint on a cheap 256GB SSD after disconnecting the HDD so Mint wasn't able to see it when it was being installed. I shift between them by selecting the boot device in BIOS and don't see GRUB's OS selection screen ever. 

 

The problem is that I'm still learning Linux and don't know if something's gone wrong. Today I was browsing the Mint file system after running sudo apt upgrade and update and I saw the Windows HDD show up in it. I was able to see the three disks / partitions in the Windows drive and was able to open them and even access the files I had on my Windows drive in Mint. 

 

I don't recall the Windows drive being visible before and now the three partitions in that drive are showing up on my Linux Mint desktop. 

 

So my question is:

 

Have I done something wrong? The reason I configured it like this with two drives is so Windows and Linux could stay separate and unknown to each other. Now I'm afraid that I run the risk of something messing up when I run updates on either OS.

 

Have attached screenshots below. Thanks for your help. 

EDIT: added filesystem screenshots from both OSes.

[Eigenvektor]

52 minutes ago, Luxzio22 said:

Have I done something wrong? The reason I configured it like this with two drives is so Windows and Linux could stay separate and unknown to each other. Now I'm afraid that I run the risk of something messing up when I run updates on either OS.

Linux being able to see your Windows partitions is normal and nothing to worry about. It won't "leak" into Windows unless you explicitly tell it to mess with these partitions. Modern Linux can also read/write NTFS so you can access the file system from there, but again it won't do it on its own.

 

Windows being able to see the other drives attached to the computer is also normal. If they are installed on the same disk, there is some risk it'll mess with your Linux installation on update, if they share the same EFI partition. But if you keep these separate, they can co-exist without issues (that's what I'm doing here).

[zinco]

1 hour ago, Luxzio22 said:

. I was able to see the three disks / partitions in the Windows drive and was able to open them and even access the files I had on my Windows drive in Mint

Yes, you can do that. lets take it this way. you have windows installed on Drive1 , and you plug in another drive called Drive2. You'll be able to see that Drive2 on Windows explorer as a usual storage drive.
Now lets say we have Linus or some other OS installed onto that other drive, and we plug it into windows, we'll still be able to see the drive and also add/delete/modify files in that drive. (doing so would corrupt the OS on that drive)

Installing an OS into a drive doesn't reserve the whole drive to the OS, only while in the OS that the restrictions are present. lets say you cant delete a Windows system file cause Windows doesn't let you. You can still boot into Linux from your other drive and delete that windows system file without restrictions, thus proving restrictions are only from the booted OS.

Above examples are vice-versa, applying to both Operating systems.

You May run the risk of accidentally modifying the files on the other drive, but that's unavoidable and you should be careful when doing stuff.

Fun Fact: If you manage to download a virus meant to run on Windows, while you're on Linux, you're not safe. Since the virus works with windows, the virus can stay in the Linux drive and when you boot into windows, can wreck havoc there. And vice-versa

[Eigenvektor]

15 minutes ago, zinco said:

we'll still be able to see the drive and also add/delete/modify files in that drive. (doing so would corrupt the OS on that drive)

Unless you explicitly mess with files in System32 or some other Windows directory, no it won't. I've copied files between Windows and Linux multiple times and it does not automatically cause things to break (note: do keep fast boot disabled).

 

15 minutes ago, zinco said:

You May run the risk of accidentally modifying the files on the other drive, but that's unavoidable and you should be careful when doing stuff.

When I open Files and click on the Windows drive, it asks me for my password before it allows me to do so. So the risk is not that great.

 

15 minutes ago, zinco said:

Fun Fact: If you manage to download a virus meant to run on Windows, while you're on Linux, you're not safe. Since the virus works with windows, the virus can stay in the Linux drive and when you boot into windows, can wreck havoc there. And vice-versa

A virus generally can't do anything unless it (or the executable it's attached to) gets executed. It would need to be copied onto the Windows partition for any chance of that, since Windows can't access ext4 by default.

[goatedpenguin]

This is the beauty of using linux ie. it allows you to see files from different drives. Now while this is a really clean feature this is still a security risk since if your Linux system were to be compromised the hacker could just yoink your browser files from the windows drive since browsers are a gold mine for hackers etc... To address this I would encrypt the windows drive as well as password protect important files on your windows system. It is also a good practice to install clamAV on a Linux system. Btw this is not only limited to windows drives if you for an example attach another drive, usb stick etc. to a linux system you can use the "mount" command to access the drive's file system.

[Luxzio22]

On 1/21/2024 at 11:57 AM, Eigenvektor said:

Linux being able to see your Windows partitions is normal and nothing to worry about. It won't "leak" into Windows unless you explicitly tell it to mess with these partitions. Modern Linux can also read/write NTFS so you can access the file system from there, but again it won't do it on its own.

That's a relief, I thought they'd be invisible to each other since they were on different drives and I installed Linux only after disconnecting the Windows drive. 

On 1/21/2024 at 11:57 AM, Eigenvektor said:

Windows being able to see the other drives attached to the computer is also normal. If they are installed on the same disk, there is some risk it'll mess with your Linux installation on update

Thankfully I installed them completely separately; making sure the Windows drive wasn't even connected to the mobo while Linux was being installed. What's the strange thing is that Windows can't see my Linux drive in File Explorer, only in Disk Management. I think it will require formatting for Windows to be be able to access and store data on it. Which it doesn't need to since its a dedicated Linux drive I won't be storing important data on but its still interesting how it doesn't seem to work both ways, at least in this individual setup. 

Though I don't know if they are on the same EFI partition, is there a way to check? 

On 1/21/2024 at 12:21 PM, zinco said:

Now lets say we have Linus or some other OS installed onto that other drive, and we plug it into windows, we'll still be able to see the drive and also add/delete/modify files in that drive. (doing so would corrupt the OS on that drive)

On 1/21/2024 at 12:31 PM, Eigenvektor said:

Unless you explicitly mess with files in System32 or some other Windows directory, no it won't. I've copied files between Windows and Linux multiple times and it does not automatically cause things to break

 I think there is a limit to what will be tolerated since I actually opened up an image file and was still able to boot into Windows afterwards without errors. What I didn't do is modify or delete a file in the Windows drive. Even as a noobie, I can't imagine Windows will be able to handle a file being deleted while its unbooted. Would it go the Recycle Bin in Windows or to the one in Linux Mint? 

On 1/21/2024 at 12:31 PM, Eigenvektor said:

When I open Files and click on the Windows drive, it asks me for my password before it allows me to do so. So the risk is not that great.

There's probably something in the background regulating this because it didn't ask for the password when I stumbled across it. I wonder if it has something to do with boot priority set in BIOS. 

2 hours ago, goatedpenguin said:

This is the beauty of using linux ie. it allows you to see files from different drives.

Yup, its interesting to see and learn stuff like this so I'm glad I finally decided to get my feet wet on Linux. Fingers crossed the next steps also come this naturally. 

2 hours ago, goatedpenguin said:

Now while this is a really clean feature this is still a security risk since if your Linux system were to be compromised the hacker could just yoink your browser files from the windows drive since browsers are a gold mine for hackers...It is also a good practice to install clamAV on a Linux system. Btw this is not only limited to windows drives if you for an example attach another drive, usb stick etc. to a linux system you can use the "mount" command to access the drive's file system.

Yes that sounds like a threat becomes plausible once you have a system like this. Thankfully I'm more careful on Linux than on Windows. 

I didn't know about AV on Linux or the mount command either. I guess that command is how so many distros specialize in data recovery. If only I'd known about it before I nuked my malfunctioning, unstarting Windows drive and wiped my Dark Souls savefiles.

 

Thankyou Eigenvektor, zinco and goatedpenguin for all the information! 

[Eigenvektor]

2 hours ago, Luxzio22 said:

That's a relief, I thought they'd be invisible to each other since they were on different drives and I installed Linux only after disconnecting the Windows drive.

As long as both drives are connected, either operating system can see them.

 

2 hours ago, Luxzio22 said:

What's the strange thing is that Windows can't see my Linux drive in File Explorer, only in Disk Management.

Windows does not show the drive in File Explorer, because it uses a file system format (e.g. ext4) that Windows does not understand. That does not mean Windows can't see the drive. It is aware of its existence, which is why it is shown in Disk Management, but it isn't usable by Windows, so it doesn't get shown in Explorer.

 

Linux on the other hand does understand the file system format used by Windows (NTFS), which is why you can access your Windows partition from Linux.

 

However, Linux can't boot from NTFS, so the drive used by Linux needs to stay ext4 or any other format natively supported by Linux.

 

If you want a partition that can be used to exchange files in either direction, you would have to format it with something like ExFAT (or FAT32, but that is limited to files with a maximum size of 4 GB). This would have to be a separate partition on one of the disks, since neither Windows nor Linux can use such a partition as a boot drive.

 

2 hours ago, Luxzio22 said:

Though I don't know if they are on the same EFI partition, is there a way to check? 

If you installed them on separate disks while the other disk was unplugged they each have their own. So nothing to worry about. You can check with a partition editor like GParted. This is what it looks like on my boot disk:

 

 

The top one with the name "EFI system partition" is the one created by Windows, the bottom one with the mount point "/boot/efi" is the one I created during my Linux installation. Since you have two separate disks, there should be one EFI partition on either disk.

[goatedpenguin]

9 hours ago, Luxzio22 said:

I guess that command is how so many distros specialize in data recovery.

Well its not only the mount command(it is to a certain degree) but lets say if you broke your mint installation and you booted on a live Debian iso, what you would usually do from there, is mount the drive and all of its paths and then chroot into /mnt which in a nutshell lets you interact with your broken system and fix whatever you broke.

Here is a good link on how to "chroot" into a broken system which is bound to happen and you should be prepared for:  https://www.suse.com/support/kb/doc/?id=000018770

While this is from a different distro your currently running, the logic is still the same and make sure you don't just blindly copy the commands given and actually understand what you are doing.

[Luxzio22]

On 1/22/2024 at 11:42 PM, Eigenvektor said:

Linux on the other hand does understand the file system format used by Windows (NTFS), which is why you can access your Windows partition from Linux.

However, Linux can't boot from NTFS, so the drive used by Linux needs to stay ext4 or any other format natively supported by Linux.

 

If you installed them on separate disks while the other disk was unplugged they each have their own. So nothing to worry about. You can check with a partition editor like GParted.

I understand, its very interesting how much you can learn from a simple oddity on your system. 

 

Thanks for the app recommendation, I installed both separately but will check with GParted just in case. 

On 1/23/2024 at 6:58 AM, goatedpenguin said:

Here is a good link on how to "chroot" into a broken system which is bound to happen and you should be prepared for: 

Thanks, I'm still getting the hang of stuff so its still above my level but hopefully I won't need to learn from experience too soon

[E-waste]

On 1/21/2024 at 1:51 AM, zinco said:

Fun Fact: If you manage to download a virus meant to run on Windows, while you're on Linux, you're not safe. Since the virus works with windows, the virus can stay in the Linux drive and when you boot into windows, can wreck havoc there. And vice-versa

This isn't right because of filesystem incompatibility.  The way your example is setup, the unwanted file, on the Linux drive, if formatted with anything other than NTFS, will not be readable on Windows.

 

Vice-versa, so if there was a Linux malware on the Windows drive... unlikely, and usually it will need user password to modify anything outside of /home directory.

 

Now, if the unwanted file in saved on the Windows drive, the example works.

[goatedpenguin]

On 1/22/2024 at 11:55 PM, Luxzio22 said:

What's the strange thing is that Windows can't see my Linux drive in File Explorer, only in Disk Management

Just like @Eigenvektor said that windows does not understand the ext4 FS, I am pretty sure that there are third party softwares like Linux Reader which can access the ext4 FS on your linux drive.