Aha, cool, thanks Mike; I started with xxd myself, and got stuff that looked enough like ELF objects that I was prepared to trust file's assessment of them as ELF objects.
My machine with non-zero content at the end: Linux hunt 4.15.0-201-generic #212-Ubuntu SMP Mon Nov 28 11:29:59 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux My machines with zeros at the end: Linux millbarge 5.4.0-139-generic #156-Ubuntu SMP Fri Jan 20 17:27:18 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux Linux wopr 5.15.0-52-generic #58-Ubuntu SMP Thu Oct 13 08:03:55 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux Linux minis 5.19.0-32-generic #33~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Mon Jan 30 17:03:34 UTC 2 x86_64 x86_64 x86_64 GNU/Linux ** Information type changed from Private Security to Public Security -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-signed-hwe-5.19 in Ubuntu. https://bugs.launchpad.net/bugs/2008823 Title: /sys/kernel/boot_params/data leaks random data Status in linux-signed-hwe-5.19 package in Ubuntu: New Bug description: Looking at /sys/kernel/boot_params/data I see that much of the 4096 byte buffer is old kernel data. It really stood out as I saw parts of email contents in there. It seems be random RAM contents from what was present before rebooting. This was seen on Ubuntu 22.04.2 LTS with kernel 5.19.0-32-generic. After rebooting again I saw a fragment of yet another email in there. A couple of ubuntu 22.10 systems show similar non-zero data, but nothing as recognizable. Nothing after the entries at the front of e820_table was zeroed out as it should be. This could leak a substantial amount of data such as encryption keys. /sys/kernel/boot_params/data is readable by all users. ProblemType: Bug DistroRelease: Ubuntu 22.04 Package: linux-image-5.19.0-32-generic 5.19.0-32.33~22.04.1 ProcVersionSignature: Ubuntu 5.19.0-32.33~22.04.1-generic 5.19.17 Uname: Linux 5.19.0-32-generic x86_64 ApportVersion: 2.20.11-0ubuntu82.3 Architecture: amd64 CasperMD5CheckResult: unknown Date: Tue Feb 28 13:24:06 2023 InstallationDate: Installed on 2019-10-17 (1229 days ago) InstallationMedia: Ubuntu-Server 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805) ProcEnviron: TERM=screen-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: linux-signed-hwe-5.19 UpgradeStatus: Upgraded to jammy on 2022-08-13 (199 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-signed-hwe-5.19/+bug/2008823/+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
