About the comment "users with a custom wsize", note that I didn't set a custom wsize.
This is the script I am using to mount the SMB 1.0 shares: https://github.com/rdiez/Tools/blob/master/MountWindowsShares/mount- windows-shares-sudo.sh There is no wsize parameter there. I did write above that the wsize value I am seeing seems to be the default, and I don't recall having adjusted any such SMB / CIFS parameter anywhere on my systems. About the comment "Most users will want to use the 6.2 HWE kernel until this is fixed", this is rather hard to do at the moment. If you install HWE (by means of linux-generic-hwe-22.04, which may be there by default), the system will not offer you a way to stay with 6.2. Under package linux-generic-hwe-22.04 you will find only one 5.15 and one 6.5 version now, so there is no easy way to go back to and stay with 6.2. I asked about this in the "original description" of this bug report, which is now hidden under a link at the top of this report. As I got no answer, I investigated further, and this is how I blocked the 6.5 kernels on a critical PC I have: echo -e "Package: linux-image*-6.5.*\nPin: release *\nPin-Priority: -1" | sudo tee /etc/apt/preferences.d/99-${USER}-prevent-upgrade-to- kernel-6.5.pref This blocking is probably problematic. First of all, if a new kernel version like 6.6 is released, the block will no longer work. There is also no guarantee that the system will not download further 5.15 kernels and evict the 6.2 kernel for lack of space in the /boot partition, as there is now nothing that requires the 6.2 version (linux-generic- hwe-22.04 got automatically uninstalled upon applying the block above). Furthermore, I also understand that 6.2 is (or will soon be) no longer supported. This is probably a shortcoming of choosing non "long term support" kernels for such HWE upgrades. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/2049634 Title: smb1: wsize blocks of bytes followed with binary zeros on copy, destroying data Status in linux package in Ubuntu: In Progress Status in linux source package in Mantic: In Progress Status in linux source package in Noble: In Progress Bug description: [Impact] Upon installing the 6.5 HWE kernel on Jammy, users with a custom wsize set will see data destruction when copying files from their systems onto a cifs smb 1.0 mount. wsize defaults to 65535 bytes, but when set to smaller values, like 16850, users will see blocks of 16850 bytes copied over, followed by 3900 binary zeros, followed by the next block of data followed by more binary zeros. A workaround is to increase wsize, but this only works for small files, as any files larger than wsize will see the bug. Most users will want to use the 6.2 HWE kernel until this is fixed. [Testcase] Start two VMs, one for the server, and the other, the client. Server ------ $ sudo apt update $ sudo apt upgrade $ sudo apt install samba $ sudo vim /etc/samba/smb.conf server min protocol = NT1 [sambashare] comment = Samba on Ubuntu path = /home/ubuntu/sambashare read only = no browsable = yes $ mkdir ~/sambashare $ sudo smbpasswd -a ubuntu Client ------ $ sudo apt update $ sudo apt install cifs-utils $ mkdir ~/share $ sudo mount -t cifs -o username=ubuntu,vers=1.0,wsize=16850 //192.168.122.172/sambashare ~/share $ ( set -o pipefail && head --bytes=$(( 55 * 1000 )) /dev/zero | openssl enc -aes-128-ctr -nosalt -pass "pass:my-seed" -iter 1 | hexdump --no-squeezing --format '40/1 "%02x"' --format '"\n"' >"testdata.txt" ) $ sha256sum testdata.txt 9ec09af020dce3270ea76531141940106f173c7243b7193a553480fb8500b3f2 testdata.txt Now copy the file to the share. Client ------ $ cp testdata.txt share/ Server ------ $ sha256sum sambashare/testdata.txt 9e573a0aa795f9cd4de4ac684a1c056dbc7d2ba5494d02e71b6225ff5f0fd866 sambashare/testdata.txt The SHA256 hash is different. If you view the file with less, you will find a block of wsize=16850 bytes, then 3900 bytes of binary zeros, followed by another wsize=16850 bytes, then 3900 bytes of binary zeros, etc. An example of a broken file is: https://launchpadlibrarian.net/712573213/testdata-back-from-server.txt [Where problems could occur] [Other info] Currently bisecting. Introduced in 6.3-rc1. Currently broken on mainline 6.8-rc3. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2049634/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
