From: Longpeng(Mike) <[email protected]>

commit d90ca42012db2863a9a30b564a2ace6016594bda upstream.

The src/dst length is not aligned with AES_BLOCK_SIZE(which is 16) in some
testcases in tcrypto.ko.

For example, the src/dst length of one of cts(cbc(aes))'s testcase is 17, the
crypto_virtio driver will set @src_data_len=16 but @dst_data_len=17 in this
case and get a wrong at then end.

  SRC: pp pp pp pp pp pp pp pp pp pp pp pp pp pp pp pp pp (17 bytes)
  EXP: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc pp (17 bytes)
  DST: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 00 (pollute the last 
bytes)
  (pp: plaintext  cc:ciphertext)

Fix this issue by limit the length of dest buffer.

Fixes: dbaf0624ffa5 ("crypto: add virtio-crypto driver")
Cc: Gonglei <[email protected]>
Cc: Herbert Xu <[email protected]>
Cc: "Michael S. Tsirkin" <[email protected]>
Cc: Jason Wang <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Longpeng(Mike) <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/crypto/virtio/virtio_crypto_algs.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -402,6 +402,7 @@ __virtio_crypto_skcipher_do_req(struct v
                goto free;
        }
 
+       dst_len = min_t(unsigned int, req->cryptlen, dst_len);
        pr_debug("virtio_crypto: src_len: %u, dst_len: %llu\n",
                        req->cryptlen, dst_len);
 


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