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Diffstat (limited to 'security/keys/encrypted-keys/encrypted.c')
-rw-r--r--security/keys/encrypted-keys/encrypted.c206
1 files changed, 75 insertions, 131 deletions
diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c
index 0010955d7876..69855ba0d3b3 100644
--- a/security/keys/encrypted-keys/encrypted.c
+++ b/security/keys/encrypted-keys/encrypted.c
@@ -11,7 +11,7 @@
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2 of the License.
*
- * See Documentation/security/keys-trusted-encrypted.txt
+ * See Documentation/security/keys/trusted-encrypted.rst
*/
#include <linux/uaccess.h>
@@ -30,6 +30,7 @@
#include <linux/scatterlist.h>
#include <linux/ctype.h>
#include <crypto/aes.h>
+#include <crypto/algapi.h>
#include <crypto/hash.h>
#include <crypto/sha.h>
#include <crypto/skcipher.h>
@@ -54,13 +55,7 @@ static int blksize;
#define MAX_DATA_SIZE 4096
#define MIN_DATA_SIZE 20
-struct sdesc {
- struct shash_desc shash;
- char ctx[];
-};
-
-static struct crypto_shash *hashalg;
-static struct crypto_shash *hmacalg;
+static struct crypto_shash *hash_tfm;
enum {
Opt_err = -1, Opt_new, Opt_load, Opt_update
@@ -141,23 +136,22 @@ static int valid_ecryptfs_desc(const char *ecryptfs_desc)
*/
static int valid_master_desc(const char *new_desc, const char *orig_desc)
{
- if (!memcmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN)) {
- if (strlen(new_desc) == KEY_TRUSTED_PREFIX_LEN)
- goto out;
- if (orig_desc)
- if (memcmp(new_desc, orig_desc, KEY_TRUSTED_PREFIX_LEN))
- goto out;
- } else if (!memcmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN)) {
- if (strlen(new_desc) == KEY_USER_PREFIX_LEN)
- goto out;
- if (orig_desc)
- if (memcmp(new_desc, orig_desc, KEY_USER_PREFIX_LEN))
- goto out;
- } else
- goto out;
+ int prefix_len;
+
+ if (!strncmp(new_desc, KEY_TRUSTED_PREFIX, KEY_TRUSTED_PREFIX_LEN))
+ prefix_len = KEY_TRUSTED_PREFIX_LEN;
+ else if (!strncmp(new_desc, KEY_USER_PREFIX, KEY_USER_PREFIX_LEN))
+ prefix_len = KEY_USER_PREFIX_LEN;
+ else
+ return -EINVAL;
+
+ if (!new_desc[prefix_len])
+ return -EINVAL;
+
+ if (orig_desc && strncmp(new_desc, orig_desc, prefix_len))
+ return -EINVAL;
+
return 0;
-out:
- return -EINVAL;
}
/*
@@ -321,53 +315,38 @@ error:
return ukey;
}
-static struct sdesc *alloc_sdesc(struct crypto_shash *alg)
-{
- struct sdesc *sdesc;
- int size;
-
- size = sizeof(struct shash_desc) + crypto_shash_descsize(alg);
- sdesc = kmalloc(size, GFP_KERNEL);
- if (!sdesc)
- return ERR_PTR(-ENOMEM);
- sdesc->shash.tfm = alg;
- sdesc->shash.flags = 0x0;
- return sdesc;
-}
-
-static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen,
+static int calc_hash(struct crypto_shash *tfm, u8 *digest,
const u8 *buf, unsigned int buflen)
{
- struct sdesc *sdesc;
- int ret;
+ SHASH_DESC_ON_STACK(desc, tfm);
+ int err;
- sdesc = alloc_sdesc(hmacalg);
- if (IS_ERR(sdesc)) {
- pr_info("encrypted_key: can't alloc %s\n", hmac_alg);
- return PTR_ERR(sdesc);
- }
+ desc->tfm = tfm;
+ desc->flags = 0;
- ret = crypto_shash_setkey(hmacalg, key, keylen);
- if (!ret)
- ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest);
- kfree(sdesc);
- return ret;
+ err = crypto_shash_digest(desc, buf, buflen, digest);
+ shash_desc_zero(desc);
+ return err;
}
-static int calc_hash(u8 *digest, const u8 *buf, unsigned int buflen)
+static int calc_hmac(u8 *digest, const u8 *key, unsigned int keylen,
+ const u8 *buf, unsigned int buflen)
{
- struct sdesc *sdesc;
- int ret;
+ struct crypto_shash *tfm;
+ int err;
- sdesc = alloc_sdesc(hashalg);
- if (IS_ERR(sdesc)) {
- pr_info("encrypted_key: can't alloc %s\n", hash_alg);
- return PTR_ERR(sdesc);
+ tfm = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(tfm)) {
+ pr_err("encrypted_key: can't alloc %s transform: %ld\n",
+ hmac_alg, PTR_ERR(tfm));
+ return PTR_ERR(tfm);
}
- ret = crypto_shash_digest(&sdesc->shash, buf, buflen, digest);
- kfree(sdesc);
- return ret;
+ err = crypto_shash_setkey(tfm, key, keylen);
+ if (!err)
+ err = calc_hash(tfm, digest, buf, buflen);
+ crypto_free_shash(tfm);
+ return err;
}
enum derived_key_type { ENC_KEY, AUTH_KEY };
@@ -385,10 +364,9 @@ static int get_derived_key(u8 *derived_key, enum derived_key_type key_type,
derived_buf_len = HASH_SIZE;
derived_buf = kzalloc(derived_buf_len, GFP_KERNEL);
- if (!derived_buf) {
- pr_err("encrypted_key: out of memory\n");
+ if (!derived_buf)
return -ENOMEM;
- }
+
if (key_type)
strcpy(derived_buf, "AUTH_KEY");
else
@@ -396,8 +374,8 @@ static int get_derived_key(u8 *derived_key, enum derived_key_type key_type,
memcpy(derived_buf + strlen(derived_buf) + 1, master_key,
master_keylen);
- ret = calc_hash(derived_key, derived_buf, derived_buf_len);
- kfree(derived_buf);
+ ret = calc_hash(hash_tfm, derived_key, derived_buf, derived_buf_len);
+ kzfree(derived_buf);
return ret;
}
@@ -480,12 +458,9 @@ static int derived_key_encrypt(struct encrypted_key_payload *epayload,
struct skcipher_request *req;
unsigned int encrypted_datalen;
u8 iv[AES_BLOCK_SIZE];
- unsigned int padlen;
- char pad[16];
int ret;
encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
- padlen = encrypted_datalen - epayload->decrypted_datalen;
req = init_skcipher_req(derived_key, derived_keylen);
ret = PTR_ERR(req);
@@ -493,11 +468,10 @@ static int derived_key_encrypt(struct encrypted_key_payload *epayload,
goto out;
dump_decrypted_data(epayload);
- memset(pad, 0, sizeof pad);
sg_init_table(sg_in, 2);
sg_set_buf(&sg_in[0], epayload->decrypted_data,
epayload->decrypted_datalen);
- sg_set_buf(&sg_in[1], pad, padlen);
+ sg_set_page(&sg_in[1], ZERO_PAGE(0), AES_BLOCK_SIZE, 0);
sg_init_table(sg_out, 1);
sg_set_buf(sg_out, epayload->encrypted_data, encrypted_datalen);
@@ -533,6 +507,7 @@ static int datablob_hmac_append(struct encrypted_key_payload *epayload,
if (!ret)
dump_hmac(NULL, digest, HASH_SIZE);
out:
+ memzero_explicit(derived_key, sizeof(derived_key));
return ret;
}
@@ -561,8 +536,8 @@ static int datablob_hmac_verify(struct encrypted_key_payload *epayload,
ret = calc_hmac(digest, derived_key, sizeof derived_key, p, len);
if (ret < 0)
goto out;
- ret = memcmp(digest, epayload->format + epayload->datablob_len,
- sizeof digest);
+ ret = crypto_memneq(digest, epayload->format + epayload->datablob_len,
+ sizeof(digest));
if (ret) {
ret = -EINVAL;
dump_hmac("datablob",
@@ -571,6 +546,7 @@ static int datablob_hmac_verify(struct encrypted_key_payload *epayload,
dump_hmac("calc", digest, HASH_SIZE);
}
out:
+ memzero_explicit(derived_key, sizeof(derived_key));
return ret;
}
@@ -584,9 +560,14 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload,
struct skcipher_request *req;
unsigned int encrypted_datalen;
u8 iv[AES_BLOCK_SIZE];
- char pad[16];
+ u8 *pad;
int ret;
+ /* Throwaway buffer to hold the unused zero padding at the end */
+ pad = kmalloc(AES_BLOCK_SIZE, GFP_KERNEL);
+ if (!pad)
+ return -ENOMEM;
+
encrypted_datalen = roundup(epayload->decrypted_datalen, blksize);
req = init_skcipher_req(derived_key, derived_keylen);
ret = PTR_ERR(req);
@@ -594,13 +575,12 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload,
goto out;
dump_encrypted_data(epayload, encrypted_datalen);
- memset(pad, 0, sizeof pad);
sg_init_table(sg_in, 1);
sg_init_table(sg_out, 2);
sg_set_buf(sg_in, epayload->encrypted_data, encrypted_datalen);
sg_set_buf(&sg_out[0], epayload->decrypted_data,
epayload->decrypted_datalen);
- sg_set_buf(&sg_out[1], pad, sizeof pad);
+ sg_set_buf(&sg_out[1], pad, AES_BLOCK_SIZE);
memcpy(iv, epayload->iv, sizeof(iv));
skcipher_request_set_crypt(req, sg_in, sg_out, encrypted_datalen, iv);
@@ -612,6 +592,7 @@ static int derived_key_decrypt(struct encrypted_key_payload *epayload,
goto out;
dump_decrypted_data(epayload);
out:
+ kfree(pad);
return ret;
}
@@ -722,6 +703,7 @@ static int encrypted_key_decrypt(struct encrypted_key_payload *epayload,
out:
up_read(&mkey->sem);
key_put(mkey);
+ memzero_explicit(derived_key, sizeof(derived_key));
return ret;
}
@@ -828,13 +810,13 @@ static int encrypted_instantiate(struct key *key,
ret = encrypted_init(epayload, key->description, format, master_desc,
decrypted_datalen, hex_encoded_iv);
if (ret < 0) {
- kfree(epayload);
+ kzfree(epayload);
goto out;
}
rcu_assign_keypointer(key, epayload);
out:
- kfree(datablob);
+ kzfree(datablob);
return ret;
}
@@ -843,8 +825,7 @@ static void encrypted_rcu_free(struct rcu_head *rcu)
struct encrypted_key_payload *epayload;
epayload = container_of(rcu, struct encrypted_key_payload, rcu);
- memset(epayload->decrypted_data, 0, epayload->decrypted_datalen);
- kfree(epayload);
+ kzfree(epayload);
}
/*
@@ -902,7 +883,7 @@ static int encrypted_update(struct key *key, struct key_preparsed_payload *prep)
rcu_assign_keypointer(key, new_epayload);
call_rcu(&epayload->rcu, encrypted_rcu_free);
out:
- kfree(buf);
+ kzfree(buf);
return ret;
}
@@ -960,33 +941,26 @@ static long encrypted_read(const struct key *key, char __user *buffer,
up_read(&mkey->sem);
key_put(mkey);
+ memzero_explicit(derived_key, sizeof(derived_key));
if (copy_to_user(buffer, ascii_buf, asciiblob_len) != 0)
ret = -EFAULT;
- kfree(ascii_buf);
+ kzfree(ascii_buf);
return asciiblob_len;
out:
up_read(&mkey->sem);
key_put(mkey);
+ memzero_explicit(derived_key, sizeof(derived_key));
return ret;
}
/*
- * encrypted_destroy - before freeing the key, clear the decrypted data
- *
- * Before freeing the key, clear the memory containing the decrypted
- * key data.
+ * encrypted_destroy - clear and free the key's payload
*/
static void encrypted_destroy(struct key *key)
{
- struct encrypted_key_payload *epayload = key->payload.data[0];
-
- if (!epayload)
- return;
-
- memzero_explicit(epayload->decrypted_data, epayload->decrypted_datalen);
- kfree(key->payload.data[0]);
+ kzfree(key->payload.data[0]);
}
struct key_type key_type_encrypted = {
@@ -999,47 +973,17 @@ struct key_type key_type_encrypted = {
};
EXPORT_SYMBOL_GPL(key_type_encrypted);
-static void encrypted_shash_release(void)
-{
- if (hashalg)
- crypto_free_shash(hashalg);
- if (hmacalg)
- crypto_free_shash(hmacalg);
-}
-
-static int __init encrypted_shash_alloc(void)
+static int __init init_encrypted(void)
{
int ret;
- hmacalg = crypto_alloc_shash(hmac_alg, 0, CRYPTO_ALG_ASYNC);
- if (IS_ERR(hmacalg)) {
- pr_info("encrypted_key: could not allocate crypto %s\n",
- hmac_alg);
- return PTR_ERR(hmacalg);
- }
-
- hashalg = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
- if (IS_ERR(hashalg)) {
- pr_info("encrypted_key: could not allocate crypto %s\n",
- hash_alg);
- ret = PTR_ERR(hashalg);
- goto hashalg_fail;
+ hash_tfm = crypto_alloc_shash(hash_alg, 0, CRYPTO_ALG_ASYNC);
+ if (IS_ERR(hash_tfm)) {
+ pr_err("encrypted_key: can't allocate %s transform: %ld\n",
+ hash_alg, PTR_ERR(hash_tfm));
+ return PTR_ERR(hash_tfm);
}
- return 0;
-
-hashalg_fail:
- crypto_free_shash(hmacalg);
- return ret;
-}
-
-static int __init init_encrypted(void)
-{
- int ret;
-
- ret = encrypted_shash_alloc();
- if (ret < 0)
- return ret;
ret = aes_get_sizes();
if (ret < 0)
goto out;
@@ -1048,14 +992,14 @@ static int __init init_encrypted(void)
goto out;
return 0;
out:
- encrypted_shash_release();
+ crypto_free_shash(hash_tfm);
return ret;
}
static void __exit cleanup_encrypted(void)
{
- encrypted_shash_release();
+ crypto_free_shash(hash_tfm);
unregister_key_type(&key_type_encrypted);
}