Based on the CONFIG_CRASH_DM_CRYPT feature, this patch adds LUKS-encrypted device dump target support to ARM64 by addressing two challenges [1], - Kdump kernel may not be able to decrypt the LUKS partition. For some machines, a system administrator may not have a chance to enter the password to decrypt the device in kdump initramfs after the 1st kernel crashes
- LUKS2 by default use the memory-hard Argon2 key derivation function which is quite memory-consuming compared to the limited memory reserved for kdump. 1st kernel will add device tree property dmcryptkeys as similar to elfcorehdr to pass the memory address of the stored info of dm-crypt keys to the kdump kernel. [1] https://lore.kernel.org/all/[email protected]/ Cc: Arnaud Lefebvre <[email protected]> Cc: Baoquan he <[email protected]> Cc: Dave Young <[email protected]> Cc: Kairui Song <[email protected]> Cc: Pingfan Liu <[email protected]> Cc: Andrew Morton <[email protected]> Signed-off-by: Coiby Xu <[email protected]> --- arch/arm64/kernel/machine_kexec_file.c | 9 +++++++++ drivers/of/fdt.c | 19 +++++++++++++++++++ drivers/of/kexec.c | 19 +++++++++++++++++++ 3 files changed, 47 insertions(+) diff --git a/arch/arm64/kernel/machine_kexec_file.c b/arch/arm64/kernel/machine_kexec_file.c index 410060ebd86d..5f3bad8ca96d 100644 --- a/arch/arm64/kernel/machine_kexec_file.c +++ b/arch/arm64/kernel/machine_kexec_file.c @@ -134,6 +134,15 @@ int load_other_segments(struct kimage *image, kexec_dprintk("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n", image->elf_load_addr, kbuf.bufsz, kbuf.memsz); + + ret = crash_load_dm_crypt_keys(image); + + if (ret == -ENOENT) { + kexec_dprintk("No dm crypt key to load\n"); + } else if (ret) { + pr_err("Failed to load dm crypt keys\n"); + goto out_err; + } } #endif diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index 331646d667b9..2b22dc7e2b5f 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -866,6 +866,24 @@ static void __init early_init_dt_check_for_elfcorehdr(unsigned long node) elfcorehdr_addr, elfcorehdr_size); } +static void __init early_init_dt_check_for_dmcryptkeys(unsigned long node) +{ + const __be32 *prop; + + if (!IS_ENABLED(CONFIG_CRASH_DM_CRYPT)) + return; + + pr_debug("Looking for dmcryptkeys property... "); + + prop = of_get_flat_dt_prop(node, "linux,dmcryptkeys", NULL); + if (!prop) + return; + + dm_crypt_keys_addr = dt_mem_next_cell(dt_root_addr_cells, &prop); + + pr_debug("dm_crypt_keys_addr=0x%llx\n", dm_crypt_keys_addr); +} + static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND; /* @@ -1097,6 +1115,7 @@ int __init early_init_dt_scan_chosen(char *cmdline) early_init_dt_check_for_initrd(node); early_init_dt_check_for_elfcorehdr(node); + early_init_dt_check_for_dmcryptkeys(node); rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l); if (rng_seed && l > 0) { diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c index 1ee2d31816ae..4bfb1ea5744e 100644 --- a/drivers/of/kexec.c +++ b/drivers/of/kexec.c @@ -432,6 +432,25 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image, if (ret) goto out; + if (image->dm_crypt_keys_addr != 0) { + ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, + "linux,dmcryptkeys", + image->dm_crypt_keys_addr, + image->dm_crypt_keys_sz); + + if (ret) + goto out; + + /* + * Avoid dmcryptkeys from being stomped on in kdump kernel by + * setting up memory reserve map. + */ + ret = fdt_add_mem_rsv(fdt, image->dm_crypt_keys_addr, + image->dm_crypt_keys_sz); + if (ret) + goto out; + } + #ifdef CONFIG_CRASH_DUMP /* add linux,usable-memory-range */ ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, base-commit: ccd1cdca5cd433c8a5dff78b69a79b31d9b77ee1 prerequisite-patch-id: af871421d3653569c735073a3d2d4915412736d7 prerequisite-patch-id: 536241bdf9240e12a5b038415875d4ce417a0892 -- 2.52.0
