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tls: rx: wrap decrypt params in a struct 

The max size of iv + aad + tail is 22B. That's smaller
than a single sg entry (32B). Don't bother with the
memory packing, just create a struct which holds the
max size of those members.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2022-07-07 18:03:11 -07:00
parent 50a07aa531
commit b89fec54fd
1 changed files with 30 additions and 30 deletions
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60
net/tls/tls_sw.c
View File

@ -50,6 +50,13 @@ struct tls_decrypt_arg {
u8 tail;
};
struct tls_decrypt_ctx {
u8 iv[MAX_IV_SIZE];
u8 aad[TLS_MAX_AAD_SIZE];
u8 tail;
struct scatterlist sg[];
};
noinline void tls_err_abort(struct sock *sk, int err)
{
WARN_ON_ONCE(err >= 0);
@ -1414,17 +1421,18 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
struct tls_context *tls_ctx = tls_get_ctx(sk);
struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
struct tls_prot_info *prot = &tls_ctx->prot_info;
int n_sgin, n_sgout, aead_size, err, pages = 0;
struct strp_msg *rxm = strp_msg(skb);
struct tls_msg *tlm = tls_msg(skb);
int n_sgin, n_sgout, nsg, mem_size, aead_size, err, pages = 0;
u8 *aad, *iv, *tail, *mem = NULL;
struct aead_request *aead_req;
struct sk_buff *unused;
struct scatterlist *sgin = NULL;
struct scatterlist *sgout = NULL;
const int data_len = rxm->full_len - prot->overhead_size;
int tail_pages = !!prot->tail_size;
struct tls_decrypt_ctx *dctx;
int iv_offset = 0;
u8 *mem;
if (darg->zc && (out_iov || out_sg)) {
if (out_iov)
@ -1446,38 +1454,30 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
/* Increment to accommodate AAD */
n_sgin = n_sgin + 1;
nsg = n_sgin + n_sgout;
aead_size = sizeof(*aead_req) + crypto_aead_reqsize(ctx->aead_recv);
mem_size = aead_size + (nsg * sizeof(struct scatterlist));
mem_size = mem_size + TLS_MAX_AAD_SIZE;
mem_size = mem_size + MAX_IV_SIZE;
mem_size = mem_size + prot->tail_size;
/* Allocate a single block of memory which contains
* aead_req || sgin[] || sgout[] || aad || iv || tail.
* This order achieves correct alignment for aead_req, sgin, sgout.
* aead_req || tls_decrypt_ctx.
* Both structs are variable length.
*/
mem = kmalloc(mem_size, sk->sk_allocation);
aead_size = sizeof(*aead_req) + crypto_aead_reqsize(ctx->aead_recv);
mem = kmalloc(aead_size + struct_size(dctx, sg, n_sgin + n_sgout),
sk->sk_allocation);
if (!mem)
return -ENOMEM;
/* Segment the allocated memory */
aead_req = (struct aead_request *)mem;
sgin = (struct scatterlist *)(mem + aead_size);
sgout = sgin + n_sgin;
aad = (u8 *)(sgout + n_sgout);
iv = aad + TLS_MAX_AAD_SIZE;
tail = iv + MAX_IV_SIZE;
dctx = (struct tls_decrypt_ctx *)(mem + aead_size);
sgin = &dctx->sg[0];
sgout = &dctx->sg[n_sgin];
/* For CCM based ciphers, first byte of nonce+iv is a constant */
switch (prot->cipher_type) {
case TLS_CIPHER_AES_CCM_128:
iv[0] = TLS_AES_CCM_IV_B0_BYTE;
dctx->iv[0] = TLS_AES_CCM_IV_B0_BYTE;
iv_offset = 1;
break;
case TLS_CIPHER_SM4_CCM:
iv[0] = TLS_SM4_CCM_IV_B0_BYTE;
dctx->iv[0] = TLS_SM4_CCM_IV_B0_BYTE;
iv_offset = 1;
break;
}
@ -1485,28 +1485,28 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
/* Prepare IV */
if (prot->version == TLS_1_3_VERSION ||
prot->cipher_type == TLS_CIPHER_CHACHA20_POLY1305) {
memcpy(iv + iv_offset, tls_ctx->rx.iv,
memcpy(&dctx->iv[iv_offset], tls_ctx->rx.iv,
prot->iv_size + prot->salt_size);
} else {
err = skb_copy_bits(skb, rxm->offset + TLS_HEADER_SIZE,
iv + iv_offset + prot->salt_size,
&dctx->iv[iv_offset] + prot->salt_size,
prot->iv_size);
if (err < 0) {
kfree(mem);
return err;
}
memcpy(iv + iv_offset, tls_ctx->rx.iv, prot->salt_size);
memcpy(&dctx->iv[iv_offset], tls_ctx->rx.iv, prot->salt_size);
}
xor_iv_with_seq(prot, iv + iv_offset, tls_ctx->rx.rec_seq);
xor_iv_with_seq(prot, &dctx->iv[iv_offset], tls_ctx->rx.rec_seq);
/* Prepare AAD */
tls_make_aad(aad, rxm->full_len - prot->overhead_size +
tls_make_aad(dctx->aad, rxm->full_len - prot->overhead_size +
prot->tail_size,
tls_ctx->rx.rec_seq, tlm->control, prot);
/* Prepare sgin */
sg_init_table(sgin, n_sgin);
sg_set_buf(&sgin[0], aad, prot->aad_size);
sg_set_buf(&sgin[0], dctx->aad, prot->aad_size);
err = skb_to_sgvec(skb, &sgin[1],
rxm->offset + prot->prepend_size,
rxm->full_len - prot->prepend_size);
@ -1518,7 +1518,7 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
if (n_sgout) {
if (out_iov) {
sg_init_table(sgout, n_sgout);
sg_set_buf(&sgout[0], aad, prot->aad_size);
sg_set_buf(&sgout[0], dctx->aad, prot->aad_size);
err = tls_setup_from_iter(out_iov, data_len,
&pages, &sgout[1],
@ -1528,7 +1528,7 @@ static int decrypt_internal(struct sock *sk, struct sk_buff *skb,
if (prot->tail_size) {
sg_unmark_end(&sgout[pages]);
sg_set_buf(&sgout[pages + 1], tail,
sg_set_buf(&sgout[pages + 1], &dctx->tail,
prot->tail_size);
sg_mark_end(&sgout[pages + 1]);
}
@ -1545,13 +1545,13 @@ fallback_to_reg_recv:
}
/* Prepare and submit AEAD request */
err = tls_do_decryption(sk, skb, sgin, sgout, iv,
err = tls_do_decryption(sk, skb, sgin, sgout, dctx->iv,
data_len + prot->tail_size, aead_req, darg);
if (darg->async)
return 0;
if (prot->tail_size)
darg->tail = *tail;
darg->tail = dctx->tail;
/* Release the pages in case iov was mapped to pages */
for (; pages > 0; pages--)