From: Jason A. Donenfeld
> Sent: 24 October 2022 17:29
>
> With char becoming unsigned by default, and with `char` alone being
> ambiguous and based on architecture, we get a warning when assigning the
> unchecked output of hex_to_bin() to that unsigned char. Mark `key` as a
> `u8`, which matches the struct's type, and then check each call to
> hex_to_bin() before casting.
>
> Cc: Kalle Valo <kvalo@xxxxxxxxxx>
> Cc: linux-wireless@xxxxxxxxxxxxxxx
> Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
> ---
> drivers/net/wireless/cisco/airo.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c
> index 10daef81c355..fb2c35bd73bb 100644
> --- a/drivers/net/wireless/cisco/airo.c
> +++ b/drivers/net/wireless/cisco/airo.c
> @@ -5232,7 +5232,7 @@ static int get_wep_tx_idx(struct airo_info *ai)
> return -1;
> }
>
> -static int set_wep_key(struct airo_info *ai, u16 index, const char *key,
> +static int set_wep_key(struct airo_info *ai, u16 index, const u8 *key,
> u16 keylen, int perm, int lock)
> {
> static const unsigned char macaddr[ETH_ALEN] = { 0x01, 0, 0, 0, 0, 0 };
> @@ -5283,7 +5283,7 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file)
> struct net_device *dev = pde_data(inode);
> struct airo_info *ai = dev->ml_priv;
> int i, rc;
> - char key[16];
> + u8 key[16];
> u16 index = 0;
> int j = 0;
>
> @@ -5311,12 +5311,22 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file)
> }
>
> for (i = 0; i < 16*3 && data->wbuffer[i+j]; i++) {
> + int val;
> +
> + if (i % 3 == 2)
> + continue;
> +
> + val = hex_to_bin(data->wbuffer[i+j]);
> + if (val < 0) {
> + airo_print_err(ai->dev->name, "WebKey passed invalid key hex");
> + return;
> + }
> switch(i%3) {
> case 0:
> - key[i/3] = hex_to_bin(data->wbuffer[i+j])<<4;
> + key[i/3] = (u8)val << 4;
> break;
> case 1:
> - key[i/3] |= hex_to_bin(data->wbuffer[i+j]);
> + key[i/3] |= (u8)val;
> break;
> }
> }
That is about the crappiest loop I've seen.
I was just going to point out that the (u8) casts aren't needed.
Something like:
for (i = 0, buf = data->wbuffer + j; i < 16; i++, buf += 3) {
int val;
if (!buf[0] || !buf[1])
break;
val = hex_to_bin(buf[0]) | hex_to_bin(buf[1]) << 8;
if (val < 0) {
airo_print_err(ai->dev->name, "WebKey passed invalid key hex");
return;
}
key[i] = val;
if (!buf[2])
break;
}
Although there should be a check for buf[2] being valid.
Any I worry about exactly what happens if there aren't 16 full bytes.
David
-
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