[PATCH 19/29] crypto: keywrap - use the new scatterwalk functions

Eric Biggers
2024-12-21T09:11:34Z

Replace calls to the deprecated function scatterwalk_copychunks() with
memcpy_{from,to}_scatterwalk(), or just memcpy_{from,to}_sglist().

Since scatterwalk_copychunks() was incorrectly being called without
being followed by scatterwalk_done(), this also fixes a bug where the
dcache of the destination page(s) was not being flushed on architectures
that need that.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
crypto/keywrap.c | 48 ++++++------------------------------------------
1 file changed, 6 insertions(+), 42 deletions(-)

diff --git a/crypto/keywrap.c b/crypto/keywrap.c
index 5ec4f94d46bd..700b7b79a93d 100644
--- a/crypto/keywrap.c
+++ b/crypto/keywrap.c
@@ -92,37 +92,10 @@ struct crypto_kw_block {
#define SEMIBSIZE 8
__be64 A;
__be64 R;
};

-/*
- * Fast forward the SGL to the "end" length minus SEMIBSIZE.
- * The start in the SGL defined by the fast-forward is returned with
- * the walk variable
- */
-static void crypto_kw_scatterlist_ff(struct scatter_walk *walk,
- struct scatterlist *sg,
- unsigned int end)
-{
- unsigned int skip = 0;
-
- /* The caller should only operate on full SEMIBLOCKs. */
- BUG_ON(end < SEMIBSIZE);
-
- skip = end - SEMIBSIZE;
- while (sg) {
- if (sg->length > skip) {
- scatterwalk_start(walk, sg);
- scatterwalk_advance(walk, skip);
- break;
- }
-
- skip -= sg->length;
- sg = sg_next(sg);
- }
-}
-
static int crypto_kw_decrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
struct crypto_kw_block block;
@@ -148,34 +121,27 @@ static int crypto_kw_decrypt(struct skcipher_request *req)
*/
src = req->src;
dst = req->dst;

for (i = 0; i < 6; i++) {
- struct scatter_walk src_walk, dst_walk;
unsigned int nbytes = req->cryptlen;

while (nbytes) {
- /* move pointer by nbytes in the SGL */
- crypto_kw_scatterlist_ff(&src_walk, src, nbytes);
+ nbytes -= SEMIBSIZE;
+
/* get the source block */
- scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,
- false);
+ memcpy_from_sglist(&block.R, src, nbytes, SEMIBSIZE);

/* perform KW operation: modify IV with counter */
block.A ^= cpu_to_be64(t);
t--;
/* perform KW operation: decrypt block */
crypto_cipher_decrypt_one(cipher, (u8 *)&block,
(u8 *)&block);

- /* move pointer by nbytes in the SGL */
- crypto_kw_scatterlist_ff(&dst_walk, dst, nbytes);
/* Copy block->R into place */
- scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,
- true);
-
- nbytes -= SEMIBSIZE;
+ memcpy_to_sglist(dst, nbytes, &block.R, SEMIBSIZE);
}

/* we now start to operate on the dst SGL only */
src = req->dst;
dst = req->dst;
@@ -229,23 +195,21 @@ static int crypto_kw_encrypt(struct skcipher_request *req)
scatterwalk_start(&src_walk, src);
scatterwalk_start(&dst_walk, dst);

while (nbytes) {
/* get the source block */
- scatterwalk_copychunks(&block.R, &src_walk, SEMIBSIZE,
- false);
+ memcpy_from_scatterwalk(&block.R, &src_walk, SEMIBSIZE);

/* perform KW operation: encrypt block */
crypto_cipher_encrypt_one(cipher, (u8 *)&block,
(u8 *)&block);
/* perform KW operation: modify IV with counter */
block.A ^= cpu_to_be64(t);
t++;

/* Copy block->R into place */
- scatterwalk_copychunks(&block.R, &dst_walk, SEMIBSIZE,
- true);
+ memcpy_to_scatterwalk(&dst_walk, &block.R, SEMIBSIZE);

nbytes -= SEMIBSIZE;
}

/* we now start to operate on the dst SGL only */
--
2.47.1