@@ -267,7 +267,6 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
struct crypto_sig *sig;
char *key, *ptr;
bool issig;
- int ksz;
int ret;
pr_devel("==>%s()\n", __func__);
@@ -302,8 +301,6 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
ret = crypto_sig_set_pubkey(sig, key, pkey->keylen);
if (ret)
goto error_free_tfm;
-
- ksz = crypto_sig_keysize(sig);
} else {
tfm = crypto_alloc_akcipher(alg_name, 0, 0);
if (IS_ERR(tfm)) {
@@ -317,8 +314,6 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
ret = crypto_akcipher_set_pub_key(tfm, key, pkey->keylen);
if (ret)
goto error_free_tfm;
-
- ksz = crypto_akcipher_maxsize(tfm);
}
ret = -EINVAL;
@@ -347,8 +342,8 @@ static int software_key_eds_op(struct kernel_pkey_params *params,
BUG();
}
- if (ret == 0)
- ret = ksz;
+ if (!issig && ret == 0)
+ ret = crypto_akcipher_maxsize(tfm);
error_free_tfm:
if (issig)
@@ -210,7 +210,7 @@ static int rsassa_pkcs1_sign(struct crypto_sig *tfm,
memset(dst, 0, pad_len);
}
- return 0;
+ return ctx->key_size;
}
static int rsassa_pkcs1_verify(struct crypto_sig *tfm,
@@ -4339,7 +4339,7 @@ static int test_sig_one(struct crypto_sig *tfm, const struct sig_testvec *vecs)
if (vecs->public_key_vec)
return 0;
- sig_size = crypto_sig_keysize(tfm);
+ sig_size = crypto_sig_maxsize(tfm);
if (sig_size < vecs->c_size) {
pr_err("alg: sig: invalid maxsize %u\n", sig_size);
return -EINVAL;
@@ -4351,13 +4351,14 @@ static int test_sig_one(struct crypto_sig *tfm, const struct sig_testvec *vecs)
/* Run asymmetric signature generation */
err = crypto_sig_sign(tfm, vecs->m, vecs->m_size, sig, sig_size);
- if (err) {
+ if (err < 0) {
pr_err("alg: sig: sign test failed: err %d\n", err);
return err;
}
/* Verify that generated signature equals cooked signature */
- if (memcmp(sig, vecs->c, vecs->c_size) ||
+ if (err != vecs->c_size ||
+ memcmp(sig, vecs->c, vecs->c_size) ||
memchr_inv(sig + vecs->c_size, 0, sig_size - vecs->c_size)) {
pr_err("alg: sig: sign test failed: invalid output\n");
hexdump(sig, sig_size);
@@ -23,7 +23,8 @@ struct crypto_sig {
* struct sig_alg - generic public key signature algorithm
*
* @sign: Function performs a sign operation as defined by public key
- * algorithm. Optional.
+ * algorithm. On success, the signature size is returned.
+ * Optional.
* @verify: Function performs a complete verify operation as defined by
* public key algorithm, returning verification status. Optional.
* @set_pub_key: Function invokes the algorithm specific set public key
@@ -186,7 +187,7 @@ static inline unsigned int crypto_sig_maxsize(struct crypto_sig *tfm)
* @dst: destination obuffer
* @dlen: destination length
*
- * Return: zero on success; error code in case of error
+ * Return: signature size on success; error code in case of error
*/
static inline int crypto_sig_sign(struct crypto_sig *tfm,
const void *src, unsigned int slen,
The callers of crypto_sig_sign() assume that the signature size is always equivalent to the key size. This happens to be true for RSA, which is currently the only algorithm implementing the ->sign() callback. But it is false e.g. for X9.62 encoded ECDSA signatures because they have variable length. Prepare for addition of a ->sign() callback to such algorithms by letting the callback return the signature size (or a negative integer on error). When testing the ->sign() callback in test_sig_one(), use crypto_sig_maxsize() instead of crypto_sig_keysize() to verify that the test vector's signature does not exceed an algorithm's maximum signature size. There has been a relatively recent effort to upstream ECDSA signature generation support which may benefit from this change: https://lore.kernel.org/linux-crypto/20220908200036.2034-1-ignat@cloudflare.com/ However the main motivation for this commit is to reduce the number of crypto_sig_keysize() callers: This function is about to be changed to return the size in bits instead of bytes and that will require amending most callers to divide the return value by 8. Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: Ignat Korchagin <ignat@cloudflare.com> --- crypto/asymmetric_keys/public_key.c | 9 ++------- crypto/rsassa-pkcs1.c | 2 +- crypto/testmgr.c | 7 ++++--- include/crypto/sig.h | 5 +++-- 4 files changed, 10 insertions(+), 13 deletions(-)