dm-crypt keeps the volume key, the IV mode seeds and, when a keyring key is used, the key description in memory for as long as the target exists. If the system crashes, they are left in memory and will end up in a crash dump.
Allocate every buffer that holds key material from the new secret pool, whose backing pages are marked by crash_memaction for the kdump kernel to wipe. The volume key is a flexible array at the end of struct crypt_config, so the whole struct moves into the pool with it. Signed-off-by: Jan Sebastian Götte <[email protected]> Assisted-by: Claude Opus 5 <[email protected]> --- drivers/md/dm-crypt.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 8e838530faab..c386b4824629 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -29,6 +29,7 @@ #include <linux/atomic.h> #include <linux/scatterlist.h> #include <linux/rbtree.h> +#include <linux/secret_pool.h> #include <linux/ctype.h> #include <asm/page.h> #include <linux/unaligned.h> @@ -486,7 +487,7 @@ static int crypt_iv_lmk_ctr(struct crypt_config *cc, struct dm_target *ti, return 0; } - lmk->seed = kzalloc(LMK_SEED_SIZE, GFP_KERNEL); + lmk->seed = secret_pool_zalloc(LMK_SEED_SIZE, GFP_KERNEL); if (!lmk->seed) { ti->error = "Error kmallocing seed storage in LMK"; return -ENOMEM; @@ -603,8 +604,8 @@ static int crypt_iv_tcw_ctr(struct crypt_config *cc, struct dm_target *ti, return -EINVAL; } - tcw->iv_seed = kzalloc(cc->iv_size, GFP_KERNEL); - tcw->whitening = kzalloc(TCW_WHITENING_SIZE, GFP_KERNEL); + tcw->iv_seed = secret_pool_zalloc(cc->iv_size, GFP_KERNEL); + tcw->whitening = secret_pool_zalloc(TCW_WHITENING_SIZE, GFP_KERNEL); if (!tcw->iv_seed || !tcw->whitening) { crypt_iv_tcw_dtr(cc); ti->error = "Error allocating seed storage in TCW"; @@ -771,7 +772,7 @@ static int crypt_iv_elephant_ctr(struct crypt_config *cc, struct dm_target *ti, struct iv_elephant_private *elephant = &cc->iv_gen_private.elephant; int r; - elephant->key = kmalloc_obj(*elephant->key); + elephant->key = secret_pool_alloc_obj(*elephant->key); if (!elephant->key) return -ENOMEM; @@ -2484,6 +2485,7 @@ static int set_key_trusted(struct crypt_config *cc, struct key *key) static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string) { char *new_key_string, *key_desc; + size_t key_string_size; int ret; struct key_type *type; struct key *key; @@ -2521,9 +2523,11 @@ static int crypt_set_keyring_key(struct crypt_config *cc, const char *key_string return -EINVAL; } - new_key_string = kstrdup(key_string, GFP_KERNEL); + key_string_size = strlen(key_string) + 1; + new_key_string = secret_pool_alloc(key_string_size, GFP_KERNEL); if (!new_key_string) return -ENOMEM; + memcpy(new_key_string, key_string, key_string_size); key = request_key(type, key_desc + 1, NULL); if (IS_ERR(key)) { @@ -2851,7 +2855,8 @@ static int crypt_ctr_auth_cipher(struct crypt_config *cc, char *cipher_api) cc->key_mac_size = crypto_ahash_digestsize(mac); crypto_free_ahash(mac); - cc->authenc_key = kmalloc(crypt_authenckey_size(cc), GFP_KERNEL); + cc->authenc_key = secret_pool_alloc(crypt_authenckey_size(cc), + GFP_KERNEL); if (!cc->authenc_key) return -ENOMEM; @@ -3201,7 +3206,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) return -EINVAL; } - cc = kzalloc_flex(*cc, key, key_size); + cc = secret_pool_zalloc_flex(*cc, key, key_size); if (!cc) { ti->error = "Cannot allocate encryption context"; return -ENOMEM; -- 2.55.0
