On Mon 14 Jun 07:06 CDT 2021, Pavel Skripkin wrote:
> Syzbot reported slab-out-of-bounds Read in
> qrtr_endpoint_post. The problem was in wrong
> _size_ type:
>
> if (len != ALIGN(size, 4) + hdrlen)
> goto err;
>
> If size from qrtr_hdr is 4294967293 (0xfffffffd), the result of
> ALIGN(size, 4) will be 0. In case of len == hdrlen and size == 4294967293
> in header this check won't fail and
>
> skb_put_data(skb, data + hdrlen, size);
>
> will read out of bound from data, which is hdrlen allocated block.
>
> Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets")
> Reported-and-tested-by: syzbot+1917d778024161609247@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
Regards,
Bjorn
> ---
> net/qrtr/qrtr.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
> index c0477bec09bd..f2efaa4225f9 100644
> --- a/net/qrtr/qrtr.c
> +++ b/net/qrtr/qrtr.c
> @@ -436,7 +436,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len)
> struct qrtr_sock *ipc;
> struct sk_buff *skb;
> struct qrtr_cb *cb;
> - unsigned int size;
> + size_t size;
> unsigned int ver;
> size_t hdrlen;
>
> --
> 2.32.0
>
