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The kdump kernel is broken on SME systems with CONFIG_IMA_KEXEC=y enabled. Debugging traced the issue back tob69a2afd5a("x86/kexec: Carry forward IMA measurement log on kexec"). Testing was previously not conducted on SME systems with CONFIG_IMA_KEXEC enabled, which led to the oversight, with the following incarnation: ... ima: No TPM chip found, activating TPM-bypass! Loading compiled-in module X.509 certificates Loaded X.509 cert 'Build time autogenerated kernel key: 18ae0bc7e79b64700122bb1d6a904b070fef2656' ima: Allocated hash algorithm: sha256 Oops: general protection fault, probably for non-canonical address 0xcfacfdfe6660003e: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.11.0-rc2+ #14 Hardware name: Dell Inc. PowerEdge R7425/02MJ3T, BIOS 1.20.0 05/03/2023 RIP: 0010:ima_restore_measurement_list Call Trace: <TASK> ? show_trace_log_lvl ? show_trace_log_lvl ? ima_load_kexec_buffer ? __die_body.cold ? die_addr ? exc_general_protection ? asm_exc_general_protection ? ima_restore_measurement_list ? vprintk_emit ? ima_load_kexec_buffer ima_load_kexec_buffer ima_init ? __pfx_init_ima init_ima ? __pfx_init_ima do_one_initcall do_initcalls ? __pfx_kernel_init kernel_init_freeable kernel_init ret_from_fork ? __pfx_kernel_init ret_from_fork_asm </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- ... Kernel panic - not syncing: Fatal exception Kernel Offset: disabled Rebooting in 10 seconds.. Adding debug printks showed that the stored addr and size of ima_kexec buffer are not decrypted correctly like: ima: ima_load_kexec_buffer, buffer:0xcfacfdfe6660003e, size:0xe48066052d5df359 Three types of setup_data info — SETUP_EFI, - SETUP_IMA, and - SETUP_RNG_SEED are passed to the kexec/kdump kernel. Only the ima_kexec buffer experienced incorrect decryption. Debugging identified a bug in early_memremap_is_setup_data(), where an incorrect range calculation occurred due to the len variable in struct setup_data ended up only representing the length of the data field, excluding the struct's size, and thus leading to miscalculation. Address a similar issue in memremap_is_setup_data() while at it. [ bp: Heavily massage. ] Fixes:b3c72fc9a7("x86/boot: Introduce setup_indirect") Signed-off-by: Baoquan He <bhe@redhat.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Tom Lendacky <thomas.lendacky@amd.com> Cc: <stable@kernel.org> Link: https://lore.kernel.org/r/20240911081615.262202-3-bhe@redhat.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.