Enable the use of zero-copy even if the AAD and/or Auth Tag are in different
buffers than the actual data, as long as each of them individually satisfies
the zero-copy conditions (i.e. the entire buffer is either in low-mem or
within a single high-mem page).
Signed-off-by: Junaid Shahid <junaids@xxxxxxxxxx>
---
arch/x86/crypto/aesni-intel_glue.c | 121 +++++++++++++++++++++++++++----------
1 file changed, 89 insertions(+), 32 deletions(-)
diff --git a/arch/x86/crypto/aesni-intel_glue.c b/arch/x86/crypto/aesni-intel_glue.c
index 03892dd80a12..2a44285ed66c 100644
--- a/arch/x86/crypto/aesni-intel_glue.c
+++ b/arch/x86/crypto/aesni-intel_glue.c
@@ -756,42 +756,91 @@ static u8 *map_buffer(struct scatterlist *sgl)
}
/*
- * Maps the sglist buffer and returns a pointer to the mapped buffer in
- * data_buf.
+ * Maps the sglist buffer and returns pointers to the mapped buffers in assoc,
+ * data and (optionally) auth_tag.
*
* If direct mapping is not feasible, then allocates a bounce buffer if one
- * isn't already available in bounce_buf, and returns a pointer to the bounce
- * buffer in data_buf.
+ * isn't already available in bounce_buf, and returns pointers within the bounce
+ * buffer in assoc, data and auth_tag.
*
- * When the buffer is no longer needed, put_request_buffer() should be called on
- * the data_buf and the bounce_buf should be freed using kfree().
+ * When the buffers are no longer needed, put_request_buffers() should be called
+ * and the bounce_buf should be freed using kfree().
*/
-static int get_request_buffer(struct scatterlist *sgl,
- unsigned long bounce_buf_size,
- u8 **data_buf, u8 **bounce_buf, bool *mapped)
+static int get_request_buffers(struct scatterlist *sgl,
+ unsigned long assoc_len, unsigned long data_len,
+ unsigned long auth_tag_len,
+ u8 **assoc, u8 **data, u8 **auth_tag,
+ u8 **bounce_buf, bool *mapped)
{
- if (sg_is_last(sgl) && is_mappable(sgl, sgl->length)) {
+ struct scatterlist sgl_data_chain[2], sgl_auth_tag_chain[2];
+ struct scatterlist *sgl_data, *sgl_auth_tag;
+
+ sgl_data = scatterwalk_ffwd(sgl_data_chain, sgl, assoc_len);
+ sgl_auth_tag = scatterwalk_ffwd(sgl_auth_tag_chain, sgl,
+ assoc_len + data_len);
+
+ if (is_mappable(sgl, assoc_len) && is_mappable(sgl_data, data_len) &&
+ (auth_tag == NULL || is_mappable(sgl_auth_tag, auth_tag_len))) {
*mapped = true;
- *data_buf = map_buffer(sgl);
+
+ *assoc = map_buffer(sgl);
+
+ if (sgl->length >= assoc_len + data_len)
+ *data = *assoc + assoc_len;
+ else
+ *data = map_buffer(sgl_data);
+
+ if (auth_tag != NULL) {
+ if (sgl_data->length >= data_len + auth_tag_len)
+ *auth_tag = *data + data_len;
+ else
+ *auth_tag = map_buffer(sgl_auth_tag);
+ }
+
return 0;
}
*mapped = false;
if (*bounce_buf == NULL) {
- *bounce_buf = kmalloc(bounce_buf_size, GFP_ATOMIC);
+ *bounce_buf = kmalloc(assoc_len + data_len + auth_tag_len,
+ GFP_ATOMIC);
if (unlikely(*bounce_buf == NULL))
return -ENOMEM;
}
- *data_buf = *bounce_buf;
+ *assoc = *bounce_buf;
+ *data = *assoc + assoc_len;
+
+ if (auth_tag != NULL)
+ *auth_tag = *data + data_len;
+
return 0;
}
-static void put_request_buffer(u8 *data_buf, bool mapped)
+static void put_request_buffers(struct scatterlist *sgl, bool mapped,
+ u8 *assoc, u8 *data, u8 *auth_tag,
+ unsigned long assoc_len,
+ unsigned long data_len,
+ unsigned long auth_tag_len)
{
- if (mapped)
- kunmap_atomic(data_buf);
+ struct scatterlist sgl_data_chain[2];
+ struct scatterlist *sgl_data;
+
+ if (!mapped)
+ return;
+
+ sgl_data = scatterwalk_ffwd(sgl_data_chain, sgl, assoc_len);
+
+ /* The unmaps need to be done in reverse order of the maps. */
+
+ if (auth_tag != NULL && sgl_data->length < data_len + auth_tag_len)
+ kunmap_atomic(auth_tag);
+
+ if (sgl->length < assoc_len + data_len)
+ kunmap_atomic(data);
+
+ kunmap_atomic(assoc);
}
/*
@@ -803,34 +852,38 @@ static void put_request_buffer(u8 *data_buf, bool mapped)
static int gcmaes_crypt(struct aead_request *req, unsigned int assoclen,
u8 *hash_subkey, u8 *iv, void *aes_ctx, bool decrypt)
{
- u8 *src, *dst, *assoc, *bounce_buf = NULL;
+ u8 *src, *src_assoc;
+ u8 *dst, *dst_assoc;
+ u8 *auth_tag;
+ u8 *bounce_buf = NULL;
bool src_mapped = false, dst_mapped = false;
struct crypto_aead *tfm = crypto_aead_reqtfm(req);
unsigned long auth_tag_len = crypto_aead_authsize(tfm);
unsigned long data_len = req->cryptlen - (decrypt ? auth_tag_len : 0);
int retval = 0;
- unsigned long bounce_buf_size = data_len + auth_tag_len + req->assoclen;
if (auth_tag_len > 16)
return -EINVAL;
- retval = get_request_buffer(req->src, bounce_buf_size, &assoc,
- &bounce_buf, &src_mapped);
+ retval = get_request_buffers(req->src, req->assoclen, data_len,
+ auth_tag_len, &src_assoc, &src,
+ (decrypt || req->src == req->dst)
+ ? &auth_tag : NULL,
+ &bounce_buf, &src_mapped);
if (retval)
goto exit;
- src = assoc + req->assoclen;
-
if (req->src == req->dst) {
+ dst_assoc = src_assoc;
dst = src;
dst_mapped = src_mapped;
} else {
- retval = get_request_buffer(req->dst, bounce_buf_size, &dst,
- &bounce_buf, &dst_mapped);
+ retval = get_request_buffers(req->dst, req->assoclen, data_len,
+ auth_tag_len, &dst_assoc, &dst,
+ decrypt ? NULL : &auth_tag,
+ &bounce_buf, &dst_mapped);
if (retval)
goto exit;
-
- dst += req->assoclen;
}
if (!src_mapped)
@@ -843,16 +896,16 @@ static int gcmaes_crypt(struct aead_request *req, unsigned int assoclen,
u8 gen_auth_tag[16];
aesni_gcm_dec_tfm(aes_ctx, dst, src, data_len, iv,
- hash_subkey, assoc, assoclen,
+ hash_subkey, src_assoc, assoclen,
gen_auth_tag, auth_tag_len);
/* Compare generated tag with passed in tag. */
- if (crypto_memneq(src + data_len, gen_auth_tag, auth_tag_len))
+ if (crypto_memneq(auth_tag, gen_auth_tag, auth_tag_len))
retval = -EBADMSG;
} else
aesni_gcm_enc_tfm(aes_ctx, dst, src, data_len, iv,
- hash_subkey, assoc, assoclen,
- dst + data_len, auth_tag_len);
+ hash_subkey, src_assoc, assoclen,
+ auth_tag, auth_tag_len);
kernel_fpu_end();
@@ -862,9 +915,13 @@ static int gcmaes_crypt(struct aead_request *req, unsigned int assoclen,
1);
exit:
if (req->dst != req->src)
- put_request_buffer(dst - req->assoclen, dst_mapped);
+ put_request_buffers(req->dst, dst_mapped, dst_assoc, dst,
+ decrypt ? NULL : auth_tag,
+ req->assoclen, data_len, auth_tag_len);
- put_request_buffer(assoc, src_mapped);
+ put_request_buffers(req->src, src_mapped, src_assoc, src,
+ (decrypt || req->src == req->dst) ? auth_tag : NULL,
+ req->assoclen, data_len, auth_tag_len);
kfree(bounce_buf);
return retval;
--
2.16.0.rc1.238.g530d649a79-goog
