6a20bd5447
UEFI Secure boot is a signature verification mechanism, designed to
prevent malicious code being loaded and executed at the early boot
stage. This makes sure that code executed is trusted by firmware.
Previously, with kexec_file_load() interface, kernel prevents unsigned
kernel image from being loaded if secure boot is enabled. So kdump will
detect whether secure boot is enabled firstly, then decide which interface
is chosen to execute, kexec_load() or kexec_file_load(). Otherwise unsigned
kernel loading will fail if secure boot enabled, and kexec_file_load() is
entered.
Now, the implementation of kexec_file_load() is adjusted in below commit.
With this change, if CONFIG_KEXEC_SIG_FORCE is not set, unsigned kernel
still has a chance to be allowed to load under some conditions.
commit 99d5cadfde2b ("kexec_file: split KEXEC_VERIFY_SIG into KEXEC_SIG
and KEXEC_SIG_FORCE")
And in the current Fedora, the CONFIG_KEXEC_SIG_FORCE is not set, only the
CONFIG_KEXEC_SIG and CONFIG_BZIMAGE_VERIFY_SIG are set on x86_64 by default.
It's time to spread kexec_file_load() onto all systems of x86_64, including
Secure-boot platforms and legacy platforms. Please refer to the following
form.
.----------------------------------------------------------------------.
| . | signed kernel | unsigned kernel |
| . types |-----------------------|-----------------------|
| . |Secure boot| Legacy |Secure boot| Legacy |
| . |-----------|-----------|-----------|-----------|
| options . | prev| now | prev| now | | | prev| now |
| . |(file|(file|(only|(file| prev| now |(only|(file|
| . |load)|load)|load)|load)| | |load)|load)|
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y | | | | | | | | |
|SIG_FORCE is not set |succ |succ |succ |succ | X | X |succ |succ |
|BZIMAGE_VERIFY_SIG=y | | | | | | | | |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y | | | | | | | | |
|SIG_FORCE is not set | | | | | | | | |
|BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail | X | X |succ |fail |
|not set | | | | | | | | |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y | | | | | | | | |
|SIG_FORCE=y |succ |succ |succ |fail | X | X |succ |fail |
|BZIMAGE_VERIFY_SIG=y | | | | | | | | |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG=y | | | | | | | | |
|SIG_FORCE=y | | | | | | | | |
|BZIMAGE_VERIFY_SIG is |fail |fail |succ |fail | X | X |succ |fail |
|not set | | | | | | | | |
|----------------------|-----|-----|-----|-----|-----|-----|-----|-----|
|KEXEC_SIG is not set | | | | | | | | |
|SIG_FORCE is not set | | | | | | | | |
|BZIMAGE_VERIFY_SIG is |fail |fail |succ |succ | X | X |succ |succ |
|not set | | | | | | | | |
----------------------------------------------------------------------
Note:
[1] The 'X' indicates that the 1st kernel(unsigned) can not boot when the
Secure boot is enabled.
Hence, in this patch, if on x86_64, let's use the kexec_file_load() only.
See if anything wrong happened in this case, in Fedora firstly for the
time being.
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
47 lines
1.9 KiB
Plaintext
47 lines
1.9 KiB
Plaintext
# Kernel Version string for the -kdump kernel, such as 2.6.13-1544.FC5kdump
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# If no version is specified, then the init script will try to find a
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# kdump kernel with the same version number as the running kernel.
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KDUMP_KERNELVER=""
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# The kdump commandline is the command line that needs to be passed off to
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# the kdump kernel. This will likely match the contents of the grub kernel
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# line. For example:
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# KDUMP_COMMANDLINE="ro root=LABEL=/"
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# Dracut depends on proper root= options, so please make sure that appropriate
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# root= options are copied from /proc/cmdline. In general it is best to append
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# command line options using "KDUMP_COMMANDLINE_APPEND=".
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# If a command line is not specified, the default will be taken from
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# /proc/cmdline
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KDUMP_COMMANDLINE=""
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# This variable lets us remove arguments from the current kdump commandline
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# as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
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# NOTE: some arguments such as crashkernel will always be removed
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KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
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# This variable lets us append arguments to the current kdump commandline
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# after processed by KDUMP_COMMANDLINE_REMOVE
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KDUMP_COMMANDLINE_APPEND="irqpoll nr_cpus=1 reset_devices cgroup_disable=memory mce=off numa=off udev.children-max=2 panic=10 acpi_no_memhotplug transparent_hugepage=never nokaslr hest_disable novmcoredd"
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# Any additional kexec arguments required. In most situations, this should
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# be left empty
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#
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# Example:
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# KEXEC_ARGS="--elf32-core-headers"
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KEXEC_ARGS=""
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#Where to find the boot image
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#KDUMP_BOOTDIR="/boot"
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#What is the image type used for kdump
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KDUMP_IMG="vmlinuz"
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#What is the images extension. Relocatable kernels don't have one
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KDUMP_IMG_EXT=""
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# Using kexec file based syscall by default
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#
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# Here, the "on" is the only valid value to enable the kexec file load and
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# anything else is equal to the "off"(disable).
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KDUMP_FILE_LOAD="on"
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