** Description changed: + [Impact] + + The current samba package on focal suffers from a bug that manifests + itselft when the SMB1 (NT1) protocol is being used. In this scenario, + the user will see regular files being presented as directories when + using GIO/gvfs to browse the samba share (e.g., via nautilus, or using + the "gio" command). Even though the SMB1 protocol is old, it is still + used by some NAS devices and therefore this issue can impact a non- + trivial number of users. + + The fix, which had to be cherry-picked from upstream, is to revert a + specific libsmb code that attempts to obtain some POSIX stat(2) + information when running on UNIX-like environments. The upstream commit + can be found here: + + https://gitlab.com/samba- + team/devel/samba/-/commit/39c910fd9cba3caf7414274b678b9eee33d7e20b + + [Test Case] + + In order to reproduce the bug, one can do: + + $ lxc launch ubuntu-daily:focal samba-bug1872476 + $ lxc shell samba-bug1872476 + + When inside the LXC container, as root: + + # apt install samba smbclient gvfs gvfs-backends dbus-x11 + # sed -i 's/^\[global\]/[global]\n client min protocol = NT1\n client max protocol = NT1\n server min protocol = NT1\n server max protocol = NT1/g' /etc/samba/smb.conf + # cat >> /etc/samba/smb.conf << __EOF__ + [testshare] + path = /testshare + readonly = no + browsable = yes + guest ok = yes + __EOF__ + # mkdir /testshare + # cat > /testshare/123.txt << __EOF__ + Hi, this is a test for samba bug 1872476. + This is a regular file, and not a directory. + __EOF__ + # ufw allow samba + # eval $(dbus-launch --sh-syntax) + # gio mount -a smb://127.0.0.1/testshare + # gio info smb://127.0.0.1/testshare/123.txt | grep '^type:' + type: directory + + As can be seen above, the regular file '123.txt' is mistakenly listed as + a directory. + + There's a PPA with a proposed fix here: + + https://launchpad.net/~sergiodj/+archive/ubuntu/samba-bug1872476-v2 + + When trying it out, it is important to umount the share and remount it + with the new package: + + # gio mount -u smb://127.0.0.1/testshare + # add-apt-repository ppa:sergiodj/samba-bug1872476-v2 + # apt update && apt upgrade + # gio mount -a smb://127.0.0.1/testshare + # gio info smb://127.0.0.1/testshare/123.txt | grep '^type:' + type: regular + + [Regression Potential] + + This change is relatively simple and has been incorporated by upstream + and by other distributions, but it touches libsmb, which is a central + area of samba. + + The POSIX stat(2) call was only made when dealing with the NT1/SMB1 + version of the samba protocol running on UNIX-like environments, which + contributes to reduce the impact of the patch. + + We can assume that there is regression potential for users of the + NT1/SMB1 protocol on UNIX-like environments that are dealing with + different types of files (regular, directory, symbolic links, etc.), + since the code that the patch modifies is responsible for obtaining the + attributes of a file. Even though the function uses fallback mechanisms + (like resorting to qpathinfo calls) to not depend solely on stat(2), the + user might experience some regression when trying to determine the type + of a file. + + [Original Description] System : Xubuntu 20.04 LTS, kernel 5.6.2 Samba : Version 4.11.6-Ubuntu problem : latest versions of samba can't mount remote disk if the remote protocol is too old. Can be fixed by adding "client min protocol = CORE" under [global] section in conf. But there is another problem, all files in remote disk are shown as folders, so we can't read these files (screenshot : https://ibb.co/g9FW14c)
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1872476 Title: Shared files are shown as folders To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/samba/+bug/1872476/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
