summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--security/keys/Kconfig2
-rw-r--r--security/keys/dh.c272
2 files changed, 171 insertions, 103 deletions
diff --git a/security/keys/Kconfig b/security/keys/Kconfig
index 00b7431a8aeb..a7a23b5541f8 100644
--- a/security/keys/Kconfig
+++ b/security/keys/Kconfig
@@ -93,9 +93,9 @@ config ENCRYPTED_KEYS
config KEY_DH_OPERATIONS
bool "Diffie-Hellman operations on retained keys"
depends on KEYS
- select MPILIB
select CRYPTO
select CRYPTO_HASH
+ select CRYPTO_DH
help
This option provides support for calculating Diffie-Hellman
public keys and shared secrets using values stored as keys
diff --git a/security/keys/dh.c b/security/keys/dh.c
index 63ac87d430db..4755d4b4f945 100644
--- a/security/keys/dh.c
+++ b/security/keys/dh.c
@@ -8,34 +8,17 @@
* 2 of the License, or (at your option) any later version.
*/
-#include <linux/mpi.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
+#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <crypto/hash.h>
+#include <crypto/kpp.h>
+#include <crypto/dh.h>
#include <keys/user-type.h>
#include "internal.h"
-/*
- * Public key or shared secret generation function [RFC2631 sec 2.1.1]
- *
- * ya = g^xa mod p;
- * or
- * ZZ = yb^xa mod p;
- *
- * where xa is the local private key, ya is the local public key, g is
- * the generator, p is the prime, yb is the remote public key, and ZZ
- * is the shared secret.
- *
- * Both are the same calculation, so g or yb are the "base" and ya or
- * ZZ are the "result".
- */
-static int do_dh(MPI result, MPI base, MPI xa, MPI p)
-{
- return mpi_powm(result, base, xa, p);
-}
-
-static ssize_t mpi_from_key(key_serial_t keyid, size_t maxlen, MPI *mpi)
+static ssize_t dh_data_from_key(key_serial_t keyid, void **data)
{
struct key *key;
key_ref_t key_ref;
@@ -56,19 +39,17 @@ static ssize_t mpi_from_key(key_serial_t keyid, size_t maxlen, MPI *mpi)
status = key_validate(key);
if (status == 0) {
const struct user_key_payload *payload;
+ uint8_t *duplicate;
payload = user_key_payload_locked(key);
- if (maxlen == 0) {
- *mpi = NULL;
+ duplicate = kmemdup(payload->data, payload->datalen,
+ GFP_KERNEL);
+ if (duplicate) {
+ *data = duplicate;
ret = payload->datalen;
- } else if (payload->datalen <= maxlen) {
- *mpi = mpi_read_raw_data(payload->data,
- payload->datalen);
- if (*mpi)
- ret = payload->datalen;
} else {
- ret = -EINVAL;
+ ret = -ENOMEM;
}
}
up_read(&key->sem);
@@ -79,6 +60,29 @@ error:
return ret;
}
+static void dh_free_data(struct dh *dh)
+{
+ kzfree(dh->key);
+ kzfree(dh->p);
+ kzfree(dh->g);
+}
+
+struct dh_completion {
+ struct completion completion;
+ int err;
+};
+
+static void dh_crypto_done(struct crypto_async_request *req, int err)
+{
+ struct dh_completion *compl = req->data;
+
+ if (err == -EINPROGRESS)
+ return;
+
+ compl->err = err;
+ complete(&compl->completion);
+}
+
struct kdf_sdesc {
struct shash_desc shash;
char ctx[];
@@ -140,7 +144,7 @@ static void kdf_dealloc(struct kdf_sdesc *sdesc)
* 5.8.1.2).
*/
static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
- u8 *dst, unsigned int dlen)
+ u8 *dst, unsigned int dlen, unsigned int zlen)
{
struct shash_desc *desc = &sdesc->shash;
unsigned int h = crypto_shash_digestsize(desc->tfm);
@@ -157,6 +161,22 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
if (err)
goto err;
+ if (zlen && h) {
+ u8 tmpbuffer[h];
+ size_t chunk = min_t(size_t, zlen, h);
+ memset(tmpbuffer, 0, chunk);
+
+ do {
+ err = crypto_shash_update(desc, tmpbuffer,
+ chunk);
+ if (err)
+ goto err;
+
+ zlen -= chunk;
+ chunk = min_t(size_t, zlen, h);
+ } while (zlen);
+ }
+
if (src && slen) {
err = crypto_shash_update(desc, src, slen);
if (err)
@@ -192,7 +212,7 @@ err:
static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
char __user *buffer, size_t buflen,
- uint8_t *kbuf, size_t kbuflen)
+ uint8_t *kbuf, size_t kbuflen, size_t lzero)
{
uint8_t *outbuf = NULL;
int ret;
@@ -203,7 +223,7 @@ static int keyctl_dh_compute_kdf(struct kdf_sdesc *sdesc,
goto err;
}
- ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, buflen);
+ ret = kdf_ctr(sdesc, kbuf, kbuflen, outbuf, buflen, lzero);
if (ret)
goto err;
@@ -221,21 +241,26 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
struct keyctl_kdf_params *kdfcopy)
{
long ret;
- MPI base, private, prime, result;
- unsigned nbytes;
+ ssize_t dlen;
+ int secretlen;
+ int outlen;
struct keyctl_dh_params pcopy;
- uint8_t *kbuf;
- ssize_t keylen;
- size_t resultlen;
+ struct dh dh_inputs;
+ struct scatterlist outsg;
+ struct dh_completion compl;
+ struct crypto_kpp *tfm;
+ struct kpp_request *req;
+ uint8_t *secret;
+ uint8_t *outbuf;
struct kdf_sdesc *sdesc = NULL;
if (!params || (!buffer && buflen)) {
ret = -EINVAL;
- goto out;
+ goto out1;
}
if (copy_from_user(&pcopy, params, sizeof(pcopy)) != 0) {
ret = -EFAULT;
- goto out;
+ goto out1;
}
if (kdfcopy) {
@@ -244,104 +269,147 @@ long __keyctl_dh_compute(struct keyctl_dh_params __user *params,
if (buflen > KEYCTL_KDF_MAX_OUTPUT_LEN ||
kdfcopy->otherinfolen > KEYCTL_KDF_MAX_OI_LEN) {
ret = -EMSGSIZE;
- goto out;
+ goto out1;
}
/* get KDF name string */
hashname = strndup_user(kdfcopy->hashname, CRYPTO_MAX_ALG_NAME);
if (IS_ERR(hashname)) {
ret = PTR_ERR(hashname);
- goto out;
+ goto out1;
}
/* allocate KDF from the kernel crypto API */
ret = kdf_alloc(&sdesc, hashname);
kfree(hashname);
if (ret)
- goto out;
+ goto out1;
}
- /*
- * If the caller requests postprocessing with a KDF, allow an
- * arbitrary output buffer size since the KDF ensures proper truncation.
- */
- keylen = mpi_from_key(pcopy.prime, kdfcopy ? SIZE_MAX : buflen, &prime);
- if (keylen < 0 || !prime) {
- /* buflen == 0 may be used to query the required buffer size,
- * which is the prime key length.
- */
- ret = keylen;
- goto out;
+ memset(&dh_inputs, 0, sizeof(dh_inputs));
+
+ dlen = dh_data_from_key(pcopy.prime, &dh_inputs.p);
+ if (dlen < 0) {
+ ret = dlen;
+ goto out1;
}
+ dh_inputs.p_size = dlen;
- /* The result is never longer than the prime */
- resultlen = keylen;
+ dlen = dh_data_from_key(pcopy.base, &dh_inputs.g);
+ if (dlen < 0) {
+ ret = dlen;
+ goto out2;
+ }
+ dh_inputs.g_size = dlen;
- keylen = mpi_from_key(pcopy.base, SIZE_MAX, &base);
- if (keylen < 0 || !base) {
- ret = keylen;
- goto error1;
+ dlen = dh_data_from_key(pcopy.private, &dh_inputs.key);
+ if (dlen < 0) {
+ ret = dlen;
+ goto out2;
}
+ dh_inputs.key_size = dlen;
- keylen = mpi_from_key(pcopy.private, SIZE_MAX, &private);
- if (keylen < 0 || !private) {
- ret = keylen;
- goto error2;
+ secretlen = crypto_dh_key_len(&dh_inputs);
+ secret = kmalloc(secretlen, GFP_KERNEL);
+ if (!secret) {
+ ret = -ENOMEM;
+ goto out2;
+ }
+ ret = crypto_dh_encode_key(secret, secretlen, &dh_inputs);
+ if (ret)
+ goto out3;
+
+ tfm = crypto_alloc_kpp("dh", CRYPTO_ALG_TYPE_KPP, 0);
+ if (IS_ERR(tfm)) {
+ ret = PTR_ERR(tfm);
+ goto out3;
+ }
+
+ ret = crypto_kpp_set_secret(tfm, secret, secretlen);
+ if (ret)
+ goto out4;
+
+ outlen = crypto_kpp_maxsize(tfm);
+
+ if (!kdfcopy) {
+ /*
+ * When not using a KDF, buflen 0 is used to read the
+ * required buffer length
+ */
+ if (buflen == 0) {
+ ret = outlen;
+ goto out4;
+ } else if (outlen > buflen) {
+ ret = -EOVERFLOW;
+ goto out4;
+ }
}
- result = mpi_alloc(0);
- if (!result) {
+ outbuf = kzalloc(kdfcopy ? (outlen + kdfcopy->otherinfolen) : outlen,
+ GFP_KERNEL);
+ if (!outbuf) {
ret = -ENOMEM;
- goto error3;
+ goto out4;
}
- /* allocate space for DH shared secret and SP800-56A otherinfo */
- kbuf = kmalloc(kdfcopy ? (resultlen + kdfcopy->otherinfolen) : resultlen,
- GFP_KERNEL);
- if (!kbuf) {
+ sg_init_one(&outsg, outbuf, outlen);
+
+ req = kpp_request_alloc(tfm, GFP_KERNEL);
+ if (!req) {
ret = -ENOMEM;
- goto error4;
+ goto out5;
}
+ kpp_request_set_input(req, NULL, 0);
+ kpp_request_set_output(req, &outsg, outlen);
+ init_completion(&compl.completion);
+ kpp_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG |
+ CRYPTO_TFM_REQ_MAY_SLEEP,
+ dh_crypto_done, &compl);
+
/*
- * Concatenate SP800-56A otherinfo past DH shared secret -- the
- * input to the KDF is (DH shared secret || otherinfo)
+ * For DH, generate_public_key and generate_shared_secret are
+ * the same calculation
*/
- if (kdfcopy &&
- copy_from_user(kbuf + resultlen, kdfcopy->otherinfo,
- kdfcopy->otherinfolen) != 0) {
- ret = -EFAULT;
- goto error5;
+ ret = crypto_kpp_generate_public_key(req);
+ if (ret == -EINPROGRESS) {
+ wait_for_completion(&compl.completion);
+ ret = compl.err;
+ if (ret)
+ goto out6;
}
- ret = do_dh(result, base, private, prime);
- if (ret)
- goto error5;
-
- ret = mpi_read_buffer(result, kbuf, resultlen, &nbytes, NULL);
- if (ret != 0)
- goto error5;
-
if (kdfcopy) {
- ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, kbuf,
- resultlen + kdfcopy->otherinfolen);
- } else {
- ret = nbytes;
- if (copy_to_user(buffer, kbuf, nbytes) != 0)
+ /*
+ * Concatenate SP800-56A otherinfo past DH shared secret -- the
+ * input to the KDF is (DH shared secret || otherinfo)
+ */
+ if (copy_from_user(outbuf + req->dst_len, kdfcopy->otherinfo,
+ kdfcopy->otherinfolen) != 0) {
ret = -EFAULT;
+ goto out6;
+ }
+
+ ret = keyctl_dh_compute_kdf(sdesc, buffer, buflen, outbuf,
+ req->dst_len + kdfcopy->otherinfolen,
+ outlen - req->dst_len);
+ } else if (copy_to_user(buffer, outbuf, req->dst_len) == 0) {
+ ret = req->dst_len;
+ } else {
+ ret = -EFAULT;
}
-error5:
- kzfree(kbuf);
-error4:
- mpi_free(result);
-error3:
- mpi_free(private);
-error2:
- mpi_free(base);
-error1:
- mpi_free(prime);
-out:
+out6:
+ kpp_request_free(req);
+out5:
+ kzfree(outbuf);
+out4:
+ crypto_free_kpp(tfm);
+out3:
+ kzfree(secret);
+out2:
+ dh_free_data(&dh_inputs);
+out1:
kdf_dealloc(sdesc);
return ret;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 11:59:42 +0000