Incoming details.
CVE-2020-14372 grub2: acpi command allows privileged user to load crafted ACPI tables when secure boot is enabled CWE-184 7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H GRUB2 enables the use of the command acpi even when secure boot is signaled by the firmware. An attacker with local root privileges to can drop a small SSDT in /boot/efi and modify grub.cfg to instruct grub to load said SSDT. The SSDT then gets run by the kernel and it overwrites the kernel lockdown configuration enabling the attacker to load unsigned kernel modules and kexec unsigned code. ==================================================================== CVE-2020-25632 grub2: use-after-free in rmmod command CWE-416 7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H The rmmod implementation for grub2 is flawed, allowing an attacker to unload a module used as dependency without checking if any other dependent module is still loaded. This leads to an use-after-free scenario possibly allowing an attacker to execute arbitrary code and by-pass Secure Boot protections. ==================================================================== CVE-2020-25647 grub2: out-of-bound write in grub_usb_device_initialize() CWE-787 6.9/CVSS:3.1/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H grub_usb_device_initialize() is called to handle USB device initialization. it reads out the descriptors it needs from the USB device and uses that data to fill in some USB data structures. grub_usb_device_initialize() performs very little bounds checking and simply assumes the USB device provides sane values. This behavior can trigger memory corruption. If properly exploited, this would lead to arbitrary code execution allowing the attacker to by-pass SecureBoot mechanism. Joseph Tartaro (IOActive), Ilja van Sprundel (IOActive) ==================================================================== CVE-2020-27749 grub2: Stack buffer overflow in grub_parser_split_cmdline CWE-121 7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H grub_parser_split_cmdline expands variable names present in the supplied command line in to their corresponding variable contents and uses a 1kB stack buffer for temporary storage without sufficient bounds checking. If the function is called with a command line that references a variable with a sufficiently large payload, it is possible to overflow the stack buffer, corrupt the stack frame and control execution. An attacker may use this to circumvent Secure Boot protections. ==================================================================== CVE-2020-27779 grub2: cutmem command allows privileged user to remove memory regions when Secure Boot is enabled CWE-285 7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H The grub2's cutmem command does not honor secure boot locking. This allows an privileged attacker to remove address ranges from memory creating an opportunity to circumvent SecureBoot protections after proper triage about grub's memory layout. ==================================================================== CVE-2021-20225 grub2: heap out-of-bounds write in short form option parser CWE-787 7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H The option parser in grub2 allows an attacker to write past the end of a heap-allocated buffer by calling certain commands with a large number of specific short forms of options. ==================================================================== CVE-2021-20233 grub2: heap out-of-bound write due to mis-calculation of space required for quoting CWE-787 7.5/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H There's a flaw on grub2 menu rendering code setparam_prefix() in the menu rendering code performs a length calculation on the assumption that expressing a quoted single quote will require 3 characters, while it actually requires 4 characters. This allow an attacker to corrupt memory by one byte for each quote in the input.
I have added grub-2.06~rc1 to the gentoo repository today. Let's give it a week for people to test it.
x86 done
ppc stable
amd64 stable
ppc64 stable
arm64 done
sparc done all arches done
Please cleanup.
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=6daa5197e9a530c71e1e78d25c1ffb356f78c972 commit 6daa5197e9a530c71e1e78d25c1ffb356f78c972 Author: Mike Gilbert <floppym@gentoo.org> AuthorDate: 2021-04-21 15:41:38 +0000 Commit: Mike Gilbert <floppym@gentoo.org> CommitDate: 2021-04-21 15:41:38 +0000 sys-boot/grub: drop 2.04-r2, 2.05_alpha20200310-r1 Bug: https://bugs.gentoo.org/773991 Signed-off-by: Mike Gilbert <floppym@gentoo.org> sys-boot/grub/Manifest | 2 - sys-boot/grub/files/2.04-sparc64-bios-boot.patch | 50 ---- sys-boot/grub/grub-2.04-r2.ebuild | 297 ----------------------- sys-boot/grub/grub-2.05_alpha20200310-r1.ebuild | 288 ---------------------- 4 files changed, 637 deletions(-)
Thanks!
Added to an existing GLSA request.
This issue was resolved and addressed in GLSA 202104-05 at https://security.gentoo.org/glsa/202104-05 by GLSA coordinator Thomas Deutschmann (whissi).
