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Message-ID: <20240425100434.198925-4-coxu@redhat.com>
Date: Thu, 25 Apr 2024 18:04:27 +0800
From: Coiby Xu <coxu@...hat.com>
To: kexec@...ts.infradead.org
Cc: Ondrej Kozina <okozina@...hat.com>,
Milan Broz <gmazyland@...il.com>,
Thomas Staudt <tstaudt@...ibm.com>,
Daniel P . Berrangé <berrange@...hat.com>,
Kairui Song <ryncsn@...il.com>,
dm-devel@...hat.com,
Jan Pazdziora <jpazdziora@...hat.com>,
Pingfan Liu <kernelfans@...il.com>,
Baoquan He <bhe@...hat.com>,
Dave Young <dyoung@...hat.com>,
linux-kernel@...r.kernel.org,
x86@...nel.org,
Dave Hansen <dave.hansen@...el.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Vivek Goyal <vgoyal@...hat.com>,
Eric Biederman <ebiederm@...ssion.com>
Subject: [PATCH v3 3/7] crash_dump: store dm keys in kdump reserved memory
When the kdump kernel image and initrd are loaded, the dm crypts keys
will be read from keyring and then stored in kdump reserved memory.
Signed-off-by: Coiby Xu <coxu@...hat.com>
---
include/linux/crash_core.h | 3 ++
include/linux/crash_dump.h | 2 +
include/linux/kexec.h | 4 ++
kernel/crash_dump_dm_crypt.c | 87 ++++++++++++++++++++++++++++++++++++
4 files changed, 96 insertions(+)
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 98825b7e0ea6..1f3d5a4fa6c1 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -37,6 +37,9 @@ static inline void arch_kexec_unprotect_crashkres(void) { }
#ifdef CONFIG_CRASH_DM_CRYPT
int crash_sysfs_dm_crypt_keys_read(char *buf);
int crash_sysfs_dm_crypt_keys_write(const char *buf, size_t count);
+int crash_load_dm_crypt_keys(struct kimage *image);
+#else
+static inline int crash_load_dm_crypt_keys(struct kimage *image) {return 0; }
#endif
#ifndef arch_crash_handle_hotplug_event
diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
index acc55626afdc..dfd8e4fe6129 100644
--- a/include/linux/crash_dump.h
+++ b/include/linux/crash_dump.h
@@ -15,6 +15,8 @@
extern unsigned long long elfcorehdr_addr;
extern unsigned long long elfcorehdr_size;
+extern unsigned long long dm_crypt_keys_addr;
+
#ifdef CONFIG_CRASH_DUMP
extern int elfcorehdr_alloc(unsigned long long *addr, unsigned long long *size);
extern void elfcorehdr_free(unsigned long long addr);
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index fc1e20d565d5..b6cedce66828 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -368,6 +368,10 @@ struct kimage {
void *elf_headers;
unsigned long elf_headers_sz;
unsigned long elf_load_addr;
+
+ /* dm crypt keys buffer */
+ unsigned long dm_crypt_keys_addr;
+ unsigned long dm_crypt_keys_sz;
};
/* kexec interface functions */
diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c
index 847499cdcd42..b9997fb53351 100644
--- a/kernel/crash_dump_dm_crypt.c
+++ b/kernel/crash_dump_dm_crypt.c
@@ -1,4 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/key.h>
+#include <linux/keyctl.h>
#include <keys/user-type.h>
#include <linux/crash_dump.h>
@@ -111,3 +113,88 @@ int crash_sysfs_dm_crypt_keys_read(char *buf)
return sprintf(buf, "%s\n", STATE_STR[state]);
}
EXPORT_SYMBOL(crash_sysfs_dm_crypt_keys_read);
+
+static int read_key_from_user_keying(struct dm_crypt_key *dm_key)
+{
+ const struct user_key_payload *ukp;
+ struct key *key;
+
+ pr_debug("Requesting key %s", dm_key->key_desc);
+ key = request_key(&key_type_logon, dm_key->key_desc, NULL);
+
+ if (IS_ERR(key)) {
+ pr_warn("No such key %s\n", dm_key->key_desc);
+ return PTR_ERR(key);
+ }
+
+ ukp = user_key_payload_locked(key);
+ if (!ukp)
+ return -EKEYREVOKED;
+
+ memcpy(dm_key->data, ukp->data, ukp->datalen);
+ dm_key->key_size = ukp->datalen;
+ pr_debug("Get dm crypt key (size=%u) %s: %8ph\n", dm_key->key_size,
+ dm_key->key_desc, dm_key->data);
+ return 0;
+}
+
+static int build_keys_header(void)
+{
+ int i, r;
+
+ for (i = 0; i < key_count; i++) {
+ r = read_key_from_user_keying(&keys_header->keys[i]);
+ if (r != 0) {
+ pr_err("Failed to read key %s\n", keys_header->keys[i].key_desc);
+ return r;
+ }
+ }
+
+ return 0;
+}
+
+int crash_load_dm_crypt_keys(struct kimage *image)
+{
+ struct kexec_buf kbuf = {
+ .image = image,
+ .buf_min = 0,
+ .buf_max = ULONG_MAX,
+ .top_down = false,
+ .random = true,
+ };
+
+ int r;
+
+ if (state == FRESH)
+ return 0;
+
+ if (key_count != keys_header->key_count) {
+ pr_err("Only record %u keys (%u in total)\n", key_count,
+ keys_header->key_count);
+ return -EINVAL;
+ }
+
+ image->dm_crypt_keys_addr = 0;
+ r = build_keys_header();
+ if (r)
+ return r;
+
+ kbuf.buffer = keys_header;
+ kbuf.bufsz = keys_header_size;
+
+ kbuf.memsz = kbuf.bufsz;
+ kbuf.buf_align = ELF_CORE_HEADER_ALIGN;
+ kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
+ r = kexec_add_buffer(&kbuf);
+ if (r) {
+ vfree((void *)kbuf.buffer);
+ return r;
+ }
+ state = LOADED;
+ image->dm_crypt_keys_addr = kbuf.mem;
+ image->dm_crypt_keys_sz = kbuf.bufsz;
+ pr_debug("Loaded dm crypt keys at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
+ image->dm_crypt_keys_addr, kbuf.bufsz, kbuf.bufsz);
+
+ return r;
+}
--
2.44.0
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