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Fix issues with grub in secure boot mode where an attacker could circumvent secure boot by using acpi and cutmem commands. Also include patches fixing similar issues. Most patches are backported directly from grub. One patch (no-insmod-on-sb.patch) comes from Debian, as the upstream implementation is too complicated to backport. CVE-2020-14372 description (from NVD [1]): A flaw was found in grub2 in versions prior to 2.06, where it incorrectly enables the usage of the ACPI command when Secure Boot is enabled. This flaw allows an attacker with privileged access to craft a Secondary System Description Table (SSDT) containing code to overwrite the Linux kernel lockdown variable content directly into memory. The table is further loaded and executed by the kernel, defeating its Secure Boot lockdown and allowing the attacker to load unsigned code. The highest threat from this vulnerability is to data confidentiality and integrity, as well as system availability. CVE-2020-27779 description (from NVD [2]): A flaw was found in grub2 in versions prior to 2.06. The cutmem command does not honor secure boot locking allowing an privileged attacker to remove address ranges from memory creating an opportunity to circumvent SecureBoot protections after proper triage about grub's memory layout. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. [1] https://nvd.nist.gov/vuln/detail/CVE-2020-14372 [2] https://nvd.nist.gov/vuln/detail/CVE-2020-27779 (From OE-Core rev: da6c0f3cfc920cea57cd409b17303bf735ccd68d) Signed-off-by: Marta Rybczynska <marta.rybczynska@huawei.com> Signed-off-by: Steve Sakoman <steve@sakoman.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
QEMU Emulation Targets ====================== To simplify development, the build system supports building images to work with the QEMU emulator in system emulation mode. Several architectures are currently supported in 32 and 64 bit variants: * ARM (qemuarm + qemuarm64) * x86 (qemux86 + qemux86-64) * PowerPC (qemuppc only) * MIPS (qemumips + qemumips64) Use of the QEMU images is covered in the Yocto Project Reference Manual. The appropriate MACHINE variable value corresponding to the target is given in brackets.