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

[Andrew Zaborowski]

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 
---
 crypto/rsa.c | 24 
 1 file changed, 24 deletions(-)

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) {
-- 
2.1.4

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

[Andrew Zaborowski]

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 
---
 crypto/rsa.c | 24 
 1 file changed, 24 deletions(-)

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) {
-- 
2.1.4

--
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More majordomo info at  http://vger.kernel.org/majordomo-info.html