[PATCH v3 16/19] net/tls: use the new scatterwalk functions

Eric Biggers
2025-02-19T18:24:31Z

Replace calls to the deprecated function scatterwalk_copychunks() with
memcpy_from_scatterwalk(), memcpy_to_scatterwalk(), or
scatterwalk_skip() as appropriate. The new functions generally behave
more as expected and eliminate the need to call scatterwalk_done() or
scatterwalk_pagedone().

However, the new functions intentionally do not advance to the next sg
entry right away, which would have broken chain_to_walk() which is
accessing the fields of struct scatter_walk directly. To avoid this,
replace chain_to_walk() with scatterwalk_get_sglist() which supports the
needed functionality.

Cc: Boris Pismenny <borisp@nvidia.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
net/tls/tls_device_fallback.c | 31 ++++++-------------------------
1 file changed, 6 insertions(+), 25 deletions(-)

diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c
index f9e3d3d90dcf5..03d508a45aaee 100644
--- a/net/tls/tls_device_fallback.c
+++ b/net/tls/tls_device_fallback.c
@@ -35,21 +35,10 @@
#include <net/ip6_checksum.h>
#include <linux/skbuff_ref.h>

#include "tls.h"

-static void chain_to_walk(struct scatterlist *sg, struct scatter_walk *walk)
-{
- struct scatterlist *src = walk->sg;
- int diff = walk->offset - src->offset;
-
- sg_set_page(sg, sg_page(src),
- src->length - diff, walk->offset);
-
- scatterwalk_crypto_chain(sg, sg_next(src), 2);
-}
-
static int tls_enc_record(struct aead_request *aead_req,
struct crypto_aead *aead, char *aad,
char *iv, __be64 rcd_sn,
struct scatter_walk *in,
struct scatter_walk *out, int *in_len,
@@ -67,20 +56,17 @@ static int tls_enc_record(struct aead_request *aead_req,
DEBUG_NET_WARN_ON_ONCE(!cipher_desc || !cipher_desc->offloadable);

buf_size = TLS_HEADER_SIZE + cipher_desc->iv;
len = min_t(int, *in_len, buf_size);

- scatterwalk_copychunks(buf, in, len, 0);
- scatterwalk_copychunks(buf, out, len, 1);
+ memcpy_from_scatterwalk(buf, in, len);
+ memcpy_to_scatterwalk(out, buf, len);

*in_len -= len;
if (!*in_len)
return 0;

- scatterwalk_pagedone(in, 0, 1);
- scatterwalk_pagedone(out, 1, 1);
-
len = buf[4] | (buf[3] << 8);
len -= cipher_desc->iv;

tls_make_aad(aad, len - cipher_desc->tag, (char *)&rcd_sn, buf[0], prot);

@@ -88,12 +74,12 @@ static int tls_enc_record(struct aead_request *aead_req,

sg_init_table(sg_in, ARRAY_SIZE(sg_in));
sg_init_table(sg_out, ARRAY_SIZE(sg_out));
sg_set_buf(sg_in, aad, TLS_AAD_SPACE_SIZE);
sg_set_buf(sg_out, aad, TLS_AAD_SPACE_SIZE);
- chain_to_walk(sg_in + 1, in);
- chain_to_walk(sg_out + 1, out);
+ scatterwalk_get_sglist(in, sg_in + 1);
+ scatterwalk_get_sglist(out, sg_out + 1);

*in_len -= len;
if (*in_len < 0) {
*in_len += cipher_desc->tag;
/* the input buffer doesn't contain the entire record.
@@ -108,14 +94,12 @@ static int tls_enc_record(struct aead_request *aead_req,

*in_len = 0;
}

if (*in_len) {
- scatterwalk_copychunks(NULL, in, len, 2);
- scatterwalk_pagedone(in, 0, 1);
- scatterwalk_copychunks(NULL, out, len, 2);
- scatterwalk_pagedone(out, 1, 1);
+ scatterwalk_skip(in, len);
+ scatterwalk_skip(out, len);
}

len -= cipher_desc->tag;
aead_request_set_crypt(aead_req, sg_in, sg_out, len, iv);

@@ -160,13 +144,10 @@ static int tls_enc_records(struct aead_request *aead_req,
cpu_to_be64(rcd_sn), &in, &out, &len, prot);
rcd_sn++;

} while (rc == 0 && len);

- scatterwalk_done(&in, 0, 0);
- scatterwalk_done(&out, 1, 0);
-
return rc;
}

/* Can't use icsk->icsk_af_ops->send_check here because the ip addresses
* might have been changed by NAT.
--
2.48.1