@@ -41,6 +41,7 @@
#include <keys/trusted-type.h>
#include <linux/device-mapper.h>
+#include <linux/kexec.h>
#include "dm-audit.h"
@@ -2388,6 +2389,8 @@ static int crypt_setkey(struct crypt_config *cc)
unsigned subkey_size;
int err = 0, i, r;
+ /* save master key to kexec */
+ kexec_save_luks_master_key(cc->key, cc->key_size);
/* Ignore extra keys (which are used for IV etc) */
subkey_size = crypt_subkey_size(cc);
@@ -3580,6 +3583,7 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv,
DMWARN("not suspended during key manipulation.");
return -EINVAL;
}
+
if (argc == 3 && !strcasecmp(argv[1], "set")) {
/* The key size may not be changed. */
key_size = get_key_size(&argv[2]);
@@ -3587,7 +3591,6 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv,
memset(argv[2], '0', strlen(argv[2]));
return -EINVAL;
}
-
ret = crypt_set_key(cc, argv[2]);
if (ret)
return ret;
@@ -205,6 +205,9 @@ int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf);
extern int kexec_add_buffer(struct kexec_buf *kbuf);
int kexec_locate_mem_hole(struct kexec_buf *kbuf);
+extern int kexec_pass_luks_master_key(void **addr, unsigned long *sz);
+extern int kexec_save_luks_master_key(u8 *key, unsigned int key_size);
+
/* Alignment required for elf header segment */
#define ELF_CORE_HEADER_ALIGN 4096
@@ -1218,3 +1218,69 @@ void __weak arch_kexec_protect_crashkres(void)
void __weak arch_kexec_unprotect_crashkres(void)
{}
+
+
+static u8 *luks_master_key;
+static unsigned int luks_master_key_size;
+
+void wipe_luks_master_key(void)
+{
+ if (luks_master_key) {
+ memset(luks_master_key, 0, luks_master_key_size * sizeof(u8));
+ kfree(luks_master_key);
+ luks_master_key = NULL;
+ }
+}
+
+static void _wipe_luks_master_key(struct work_struct *dummy)
+{
+ wipe_luks_master_key();
+}
+
+static DECLARE_DELAYED_WORK(wipe_luks_master_key_work, _wipe_luks_master_key);
+
+static unsigned __read_mostly wipe_key_delay = 3600; /* 1 hour */
+
+int kexec_save_luks_master_key(u8 *key, unsigned int key_size)
+{
+ if (luks_master_key) {
+ memset(luks_master_key, 0, luks_master_key_size * sizeof(u8));
+ kfree(luks_master_key);
+ }
+
+ luks_master_key = kmalloc(key_size * sizeof(u8), GFP_KERNEL);
+
+ if (!luks_master_key)
+ return -ENOMEM;
+ memcpy(luks_master_key, key, key_size * sizeof(u8));
+ luks_master_key_size = key_size;
+ pr_debug("LUKS master key (size=%u): %64ph\n", key_size, luks_master_key);
+ schedule_delayed_work(&wipe_luks_master_key_work,
+ round_jiffies_relative(wipe_key_delay * HZ));
+ return 0;
+}
+EXPORT_SYMBOL(kexec_save_luks_master_key);
+
+int kexec_pass_luks_master_key(void **addr, unsigned long *sz)
+{
+ unsigned long luks_key_sz;
+ unsigned char *buf;
+ unsigned int *size_ptr;
+
+ if (!luks_master_key)
+ return -EINVAL;
+
+ luks_key_sz = sizeof(unsigned int) + luks_master_key_size * sizeof(u8);
+
+ buf = vzalloc(luks_key_sz);
+ if (!buf)
+ return -ENOMEM;
+
+ size_ptr = (unsigned int *)buf;
+ memcpy(size_ptr, &luks_master_key_size, sizeof(unsigned int));
+ memcpy(size_ptr + 1, luks_master_key, luks_master_key_size * sizeof(u8));
+ *addr = buf;
+ *sz = luks_key_sz;
+ wipe_luks_master_key();
+ return 0;
+}
After receiving the LUKS master key from driver/md/dm-crypt, kdump has 1 hour at maximum to ask kexec to pass the key before the key gets wiped by kexec. And after kdump retrieves the key, the key will be wiped immediately. Signed-off-by: Coiby Xu <coxu@redhat.com> --- drivers/md/dm-crypt.c | 5 +++- include/linux/kexec.h | 3 ++ kernel/kexec_core.c | 66 +++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 73 insertions(+), 1 deletion(-)