On Tue, 31 Jan 2012 11:52:01 +0300
Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> We should check that we're not copying memory from beyond the end of the
> blob.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
>
> diff --git a/fs/cifs/sess.c b/fs/cifs/sess.c
> index d85efad..eb76741 100644
> --- a/fs/cifs/sess.c
> +++ b/fs/cifs/sess.c
> @@ -395,6 +395,10 @@ static int decode_ntlmssp_challenge(char *bcc_ptr, int blob_len,
> ses->ntlmssp->server_flags = le32_to_cpu(pblob->NegotiateFlags);
> tioffset = le32_to_cpu(pblob->TargetInfoArray.BufferOffset);
> tilen = le16_to_cpu(pblob->TargetInfoArray.Length);
> + if (tioffset > blob_len || tioffset + tilen > blob_len) {
> + cERROR(1, "tioffset + tilen too high %u + %u", tioffset, tilen);
> + return -EINVAL;
> + }
Good catch.
Do we really need a || here though? Would it not be sufficient to check
if tioffset + tilen > blob_len? Or are you concerned about that value
wrapping?
> if (tilen) {
> ses->auth_key.response = kmalloc(tilen, GFP_KERNEL);
> if (!ses->auth_key.response) {
> --
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--
Jeff Layton <jlayton@xxxxxxxxxx>
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