For keys stored in shmem only the ChaCha20-Poly1305 key is reachable here, so wiping it is enough to render the payload unreadable.
Used by CONFIG_CRASH_WIPE_SECRETS. Signed-off-by: Jan Sebastian Götte <[email protected]> --- security/keys/big_key.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/security/keys/big_key.c b/security/keys/big_key.c index 268f702df380..c01a212bec90 100644 --- a/security/keys/big_key.c +++ b/security/keys/big_key.c @@ -8,6 +8,7 @@ #define pr_fmt(fmt) "big_key: "fmt #include <linux/init.h> +#include <linux/crash_core.h> #include <linux/seq_file.h> #include <linux/file.h> #include <linux/shmem_fs.h> @@ -35,6 +36,8 @@ struct big_key_payload { */ #define BIG_KEY_FILE_THRESHOLD (sizeof(struct inode) + sizeof(struct dentry)) +static void big_key_wipe(struct key *key); + /* * big_key defined keys take an arbitrary string as the description and an * arbitrary blob of data as the payload @@ -46,6 +49,7 @@ struct key_type key_type_big_key = { .instantiate = generic_key_instantiate, .revoke = big_key_revoke, .destroy = big_key_destroy, + .wipe = big_key_wipe, .describe = big_key_describe, .read = big_key_read, .update = big_key_update, @@ -279,6 +283,19 @@ long big_key_read(const struct key *key, char *buffer, size_t buflen) return ret; } +static void big_key_wipe(struct key *key) +{ + struct big_key_payload *payload = to_big_key_payload(key->payload); + + if (payload->data) { + if (payload->length > BIG_KEY_FILE_THRESHOLD) + crash_wipe_memzero(payload->data, + CHACHA20POLY1305_KEY_SIZE); + else + crash_wipe_memzero(payload->data, payload->length); + } +} + /* * Register key type */ -- 2.53.0
