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kumquat-buildroot/boot/grub2/0073-libgcrypt-mpi-Fix-possible-unintended-sign-extension.patch

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boot/grub2: Backport 2021/03/02 securify fixes Details: https://lists.gnu.org/archive/html/grub-devel/2021-03/msg00007.html As detailed in commit 7e64a050fbd9add07ed84d48054ffee1b659d079, it is difficult to utilize the upstream patches directly, so a number of patches include changes to generated files so that we don't need invoke the gentpl.py script. In addition to the security fixes, these required patches has been backported: f76a27996 efi: Make shim_lock GUID and protocol type public 04ae030d0 efi: Return grub_efi_status_t from grub_efi_get_variable() ac5c93675 efi: Add a function to read EFI variables with attributes d7e54b2e5 efi: Add secure boot detection The following security issues are fixed: CVE-2020-14372 grub2: The 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 lock down configuration enabling the attacker to load unsigned kernel modules and kexec unsigned code. Reported-by: Máté Kukri ******************************************************************************* 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. Reported-by: Chris Coulson (Canonical) ******************************************************************************* 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 Secure Boot mechanism. Reported-by: Joseph Tartaro (IOActive) and 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. Reported-by: Chris Coulson (Canonical) ******************************************************************************* CVE-2020-27779 grub2: The 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 Secure Boot protections after proper triage about grub's memory layout. Reported-by: Teddy Reed ******************************************************************************* CVE-2021-3418 - grub2: GRUB 2.05 reintroduced CVE-2020-15705 CWE-281 6.4/CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H The GRUB2 upstream reintroduced the CVE-2020-15705. This refers to a distro specific flaw which made upstream in the mentioned version. If certificates that signed GRUB2 are installed into db, GRUB2 can be booted directly. It will then boot any kernel without signature validation. The booted kernel will think it was booted in Secure Boot mode and will implement lock down, yet it could have been tampered. This flaw only affects upstream and distributions using the shim_lock verifier. Reported-by: Dimitri John Ledkov (Canonical) ******************************************************************************* 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. Reported-by: Daniel Axtens (IBM) ******************************************************************************* 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. Reported-by: Daniel Axtens (IBM) ******************************************************************************* Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com> Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
2021-03-11 10:53:06 +01:00
From e8814c811132a70f9b55418f7567378a34ad3883 Mon Sep 17 00:00:00 2001
From: Darren Kenny <darren.kenny@oracle.com>
Date: Tue, 3 Nov 2020 16:43:37 +0000
Subject: [PATCH] libgcrypt/mpi: Fix possible unintended sign extension
The array of unsigned char gets promoted to a signed 32-bit int before
it is finally promoted to a size_t. There is the possibility that this
may result in the signed-bit being set for the intermediate signed
32-bit int. We should ensure that the promotion is to the correct type
before we bitwise-OR the values.
Fixes: CID 96697
Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Stefan Sørensen <stefan.sorensen@spectralink.com>
---
grub-core/lib/libgcrypt-grub/mpi/mpicoder.c | 2 +-
grub-core/lib/libgcrypt/mpi/mpicoder.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c b/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c
index 3d55dfc..faf1cd6 100644
--- a/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c
+++ b/grub-core/lib/libgcrypt-grub/mpi/mpicoder.c
@@ -460,7 +460,7 @@ gcry_mpi_scan (struct gcry_mpi **ret_mpi, enum gcry_mpi_format format,
if (len && len < 4)
return gcry_error (GPG_ERR_TOO_SHORT);
- n = (s[0] << 24 | s[1] << 16 | s[2] << 8 | s[3]);
+ n = ((size_t)s[0] << 24 | (size_t)s[1] << 16 | (size_t)s[2] << 8 | (size_t)s[3]);
s += 4;
if (len)
len -= 4;
diff --git a/grub-core/lib/libgcrypt/mpi/mpicoder.c b/grub-core/lib/libgcrypt/mpi/mpicoder.c
index a3435ed..7ecad27 100644
--- a/grub-core/lib/libgcrypt/mpi/mpicoder.c
+++ b/grub-core/lib/libgcrypt/mpi/mpicoder.c
@@ -458,7 +458,7 @@ gcry_mpi_scan (struct gcry_mpi **ret_mpi, enum gcry_mpi_format format,
if (len && len < 4)
return gcry_error (GPG_ERR_TOO_SHORT);
- n = (s[0] << 24 | s[1] << 16 | s[2] << 8 | s[3]);
+ n = ((size_t)s[0] << 24 | (size_t)s[1] << 16 | (size_t)s[2] << 8 | (size_t)s[3]);
s += 4;
if (len)
len -= 4;
--
2.14.2
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