Re: [PATCH] iscsi-target: Make buf param of iscsit_do_crypto_hash_buf()const void *

From: Geert Uytterhoeven
Date: Fri May 03 2013 - 17:22:44 EST


On Fri, May 3, 2013 at 11:15 PM, Geert Uytterhoeven
<geert@xxxxxxxxxxxxxx> wrote:
> --- a/drivers/target/iscsi/iscsi_target.c
> +++ b/drivers/target/iscsi/iscsi_target.c

> @@ -3585,9 +3575,8 @@ static int iscsit_send_reject(
> }
>
> if (conn->conn_ops->DataDigest) {
> - iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
> - (unsigned char *)cmd->buf_ptr, ISCSI_HDR_LEN,
> - 0, NULL, (u8 *)&cmd->data_crc);
> + iscsit_do_crypto_hash_buf(&conn->conn_tx_hash, cmd->buf_ptr,
> + ISCSI_HDR_LEN, 0, NULL, (u8 *)&cmd->data_crc);

BTW, there are serious issues with casting pointers to u32s to pointers to u8s
for the last two output parameters of iscsit_do_crypto_hash_buf() (pad_bytes
and data_crc):
1. It's not endian-safe,
2. In many cases, the original u32 was not initialized at all, so the other 24
bits contain garbage. This will cause 32-bit comparisons like

if (checksum != data_crc)

to fail in unpredictable ways.

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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