Hi Dan,
On Thursday 31 of January 2013 10:16:46 Dan Carpenter wrote:
> If gb_len is less than 3 it would cause an integer underflow and
> possibly memory corruption in nfc_llcp_parse_gb_tlv().
>
> I removed the old test for gb_len == 0. I also removed the test for
> ->remote_gb == NULL. It's not possible for ->remote_gb to be NULL and
> we have already dereferenced ->remote_gb_len so it's too late to test.
>
> The old test return -ENODEV but my test returns -EINVAL.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> diff --git a/net/nfc/llcp/llcp.c b/net/nfc/llcp/llcp.c
> index 85bc75c..746f5a2 100644
> --- a/net/nfc/llcp/llcp.c
> +++ b/net/nfc/llcp/llcp.c
> @@ -549,14 +549,13 @@ int nfc_llcp_set_remote_gb(struct nfc_dev *dev, u8 *gb, u8 gb_len)
> pr_err("No LLCP device\n");
> return -ENODEV;
> }
> + if (gb_len < 3)
> + return -EINVAL;
Maybe define NFC_MIN_GT_LEN and test it together with NFC_MAX_GT_LEN in
nfc_set_remote_general_bytes() ?
>
> memset(local->remote_gb, 0, NFC_MAX_GT_LEN);
> memcpy(local->remote_gb, gb, gb_len);
> local->remote_gb_len = gb_len;
>
> - if (local->remote_gb == NULL || local->remote_gb_len == 0)
> - return -ENODEV;
> -
> if (memcmp(local->remote_gb, llcp_magic, 3)) {
> pr_err("MAC does not support LLCP\n");
> return -EINVAL;
--
BR
Szymon Janc
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