What Kernel version is used in Asuswrt-Merlin and Is there ACL support?

[Jimbok]

The OEM Firmware 2.6.36.4brcmarm kernel, Does not seem to have ACL support (Acount Control List) for NTFS and EXt4, unless i'm missing something. I'm wondering if Asuswrt-Merlin supports it

 

[System Error Message]

I dont think you would use ACL for file systems, i think it would be user control instead as you would do on linux.

 

[microchip]

Asuswrt-Merlin does not replace the kernel. it only enhances and fixes user-space issues

 

[Jimbok]

I dont think you would use ACL for file systems, i think it would be user control instead as you would do on linux.

Yes but this has some limitations on NTFS, basically if a parent folder Has read only permissions, any subfolder(child) to it doesnt seem to allow Write acces
Example:
/tmp/Storage/Folder/ drwxrwxr-x
/tmp/Storage/Folder/Subfolder drwxrwxrwx

 

[ColinTaylor]

The OEM Firmware 2.6.36.4brcmarm kernel, Does not seem to have ACL support (Acount Control List) for NTFS and EXt4, unless i'm missing something. I'm wondering if Asuswrt-Merlin supports it

Merlin's firmware uses the same NTFS driver that OEM uses. So no, there is no ACL support.

This is a frequent source of problems for people that have formatted an external drive as NTFS when attached to their PC and assigned limited rights to directories, and then attached it to the router.

 

[Jimbok]

Merlin's firmware uses the same NTFS driver that OEM uses. So no, there is no ACL support.

This is a frequent source of problems for people that have formatted an external drive as NTFS when attached to their PC and assigned limited rights to directories, and then attached it to the router.

Ok, Then is there a fix?

 

[ColinTaylor]

Ok, Then is there a fix?

Format the drive while it is attached to the router using something like ext3/4.

 

[Jimbok]

Format the drive while it is attached to the router using something like ext3/4.

This is not a real solution, to be honest. Whenever an OS misbehaves you can reinstall it but, it does not teach you much. I figured out the issue though, which is in how AsusWRT handles permissions that is: When you give a user read or write permissions from inside the WebUI it writes these in a ".__SomeUser_var.txt" to the root of any attached Storage Device, and this supercedes any Linux style permission(read write execute) the values i noticed were 000, 100, 300, 331 (no acces, read acces, write acces, and root acces) 331 seems to be special. The solution is in giving a user write acces(300) in the WebUI. Then connecting to it through SSH and sending the command "chmod 775 -R *" this will then use the normal permission style you'd expect in Linux, Giving write acces to a Subfolder whom's Parent is read only, works perfectly

As far as i can tell these ".__SomeUser_var.txt" style permissions mapping seem to a redundant and a very limited way of handling permissions

 

[ColinTaylor]

@Jimbok Yes you are correct about the way the router handles SMB/FTP permissions. Sorry, from your original post I thought you were just talking about Unix permissions.

Bear in mind that the router is not a Linux distribution. At the Unix level there is essentially only one user account, admin (which is root renamed). Therefore all files should be accessible to any services that are running on the router.

But it is annoying/confusing that ASUS decided to design their own non-standard version of SMB and FTP that doesn't use any underlying Unix permissions.

 

[RMerlin]

OS-mapped permissions allow these to be filesystem-agnostic. Remember for instance that FAT32 has no permission support, and this filesystem is used by the vast majority of USB thumbdrives.

 

[Jimbok]

OS-mapped permissions allow these to be filesystem-agnostic. Remember for instance that FAT32 has no permission support, and this filesystem is used by the vast majority of USB thumbdrives.

You are right but it should be possible to impliment FS specific permission handling, or just create exception for file systems that do not support permissions. Asus's decission to universely apply it to all, even the ones that do support this, Needlessly creates conflicts

 

[RMerlin]

You are right but it should be possible to impliment FS specific permission handling, or just create exception for file systems that do not support permissions. Asus's decission to universely apply it to all, even the ones that do support this, Needlessly creates conflicts

Keep in mind this is a router, not a NAS. Any NAS-like functionality is bound to be very basic, as it's not the focus of their development team.

 

[sfx2000]

The OEM Firmware 2.6.36.4brcmarm kernel, Does not seem to have ACL support (Acount Control List) for NTFS and EXt4, unless i'm missing something. I'm wondering if Asuswrt-Merlin supports it

I wonder what's going to happen when 2.6.36 goes end of life - 2.6.32 went EOL in Jan 2016, so 2.6.36 can't be that far behind - which will complicate things for many Linux embedded developers... and it might impact toolchains as well...

(EOL doesn't mean that things will stop, just means that upstream bug fixes/security updates will not consider these older kernels).

Quick check on my NAS unit - it's on 3.12.6 (QNAP QTS 4.2.0)...

 

[DarkBBQ]

Format the drive while it is attached to the router using something like ext3/4.

What do I have to do to get ext4 working on my merlin rt-n66u?

 

[ColinTaylor]

I think only ext2 and ext3 are supported on the N66U.

http://www.snbforums.com/threads/usb-file-system.15134/#post-102395
http://www.snbforums.com/threads/ext4-on-rt-n66u-possible.22561/

 

[loadbang]

2.6.36 was released somewhere circa 2010, I have no idea why Asus still use this outdated and potentially insecure kernel. Really would like ext4 and BTRFS support.

 

[sfx2000]

2.6.36 was released somewhere circa 2010, I have no idea why Asus still use this outdated and potentially insecure kernel. Really would like ext4 and BTRFS support.

No problem running an old kernel - upstream patches are still there, and from what I've seen, Asus has been pretty good about merging them in where applicable.

The big challenge with bringing the kernel forward, and this is the case with any software, is that API's inside the kernel change, and if one has ever viewed the number of packages - both source and binary third party, moving to a new kernel is non-trivial...

 

[RMerlin]

2.6.36 was released somewhere circa 2010, I have no idea why Asus still use this outdated and potentially insecure kernel. Really would like ext4 and BTRFS support.

Ask Broadcom, not Asus. Broadcom are the ones who decided to use that kernel in their SDK.

2.6.36 does support ext4, and so does Asuswrt.

 

[sfx2000]

Ask Broadcom, not Asus. Broadcom are the ones who decided to use that kernel in their SDK.

2.6.36 does support ext4, and so does Asuswrt

Would be interesting to see where other Broadcom based OEM's are at - my guess is close to the same, if not the same, as what AsusWRT is based on...

 

[RMerlin]

Would be interesting to see where other Broadcom based OEM's are at - my guess is close to the same, if not the same, as what AsusWRT is based on...

Netgear, DLink and Linksys are all on the same 2.6.36 kernel, plus or minus a few custom patches of their own.

The kernel is part of BCM's SDK, with a lot of patches and BCM-specific code.