diff mbox

[2/4] crypto: rsa: only require output buffers as big as needed.

Message ID 1447412495-4370-2-git-send-email-andrew.zaborowski@intel.com (mailing list archive)
State Accepted
Delegated to: Herbert Xu
Headers show

Commit Message

Andrew Zaborowski Nov. 13, 2015, 11:01 a.m. UTC 
rhe RSA operations explicitly left-align the integers being written
skipping any leading zero bytes, but still require the output buffers to
include just enough space for the integer + the leading zero bytes.
Since the size of integer + the leading zero bytes (i.e. the key modulus
size) can now be obtained more easily through crypto_akcipher_maxsize
change the operations to only require as big a buffer as actually needed
if the caller has that information.  The semantics for request->dst_len
don't change.

Signed-off-by: Andrew Zaborowski <andrew.zaborowski@intel.com>
---
 crypto/rsa.c | 24 ------------------------
 1 file changed, 24 deletions(-)
diff mbox

Patch

diff --git a/crypto/rsa.c b/crypto/rsa.c
index 1093e04..58aad69 100644
--- a/crypto/rsa.c
+++ b/crypto/rsa.c
@@ -91,12 +91,6 @@  static int rsa_enc(struct akcipher_request *req)
 		goto err_free_c;
 	}
 
-	if (req->dst_len < mpi_get_size(pkey->n)) {
-		req->dst_len = mpi_get_size(pkey->n);
-		ret = -EOVERFLOW;
-		goto err_free_c;
-	}
-
 	ret = -ENOMEM;
 	m = mpi_read_raw_from_sgl(req->src, req->src_len);
 	if (!m)
@@ -136,12 +130,6 @@  static int rsa_dec(struct akcipher_request *req)
 		goto err_free_m;
 	}
 
-	if (req->dst_len < mpi_get_size(pkey->n)) {
-		req->dst_len = mpi_get_size(pkey->n);
-		ret = -EOVERFLOW;
-		goto err_free_m;
-	}
-
 	ret = -ENOMEM;
 	c = mpi_read_raw_from_sgl(req->src, req->src_len);
 	if (!c)
@@ -180,12 +168,6 @@  static int rsa_sign(struct akcipher_request *req)
 		goto err_free_s;
 	}
 
-	if (req->dst_len < mpi_get_size(pkey->n)) {
-		req->dst_len = mpi_get_size(pkey->n);
-		ret = -EOVERFLOW;
-		goto err_free_s;
-	}
-
 	ret = -ENOMEM;
 	m = mpi_read_raw_from_sgl(req->src, req->src_len);
 	if (!m)
@@ -225,12 +207,6 @@  static int rsa_verify(struct akcipher_request *req)
 		goto err_free_m;
 	}
 
-	if (req->dst_len < mpi_get_size(pkey->n)) {
-		req->dst_len = mpi_get_size(pkey->n);
-		ret = -EOVERFLOW;
-		goto err_free_m;
-	}
-
 	ret = -ENOMEM;
 	s = mpi_read_raw_from_sgl(req->src, req->src_len);
 	if (!s) {