On Wed, May 18, 2022 at 12:16:55PM +0200, David Marchand wrote:
> GCC 12 raises the following warning:
>
> In file included from ../lib/mempool/rte_mempool.h:46,
> from ../lib/mbuf/rte_mbuf.h:38,
> from ../lib/vhost/vhost_crypto.c:7:
> ../lib/vhost/vhost_crypto.c: In function ‘rte_vhost_crypto_fetch_requests’:
> ../lib/eal/x86/include/rte_memcpy.h:371:9: warning: array subscript 1 is
> outside array bounds of ‘struct virtio_crypto_op_data_req[1]’
> [-Warray-bounds]
> 371 | rte_mov32((uint8_t *)dst + 3 * 32, (const uint8_t *)src + 3 * 32);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../lib/vhost/vhost_crypto.c:1178:42: note: while referencing ‘req’
> 1178 | struct virtio_crypto_op_data_req req;
> | ^~~
>
> Check that copied length is within req boundaries.
>
> Fixes: 3c79609fda7c ("vhost/crypto: handle virtually non-contiguous buffers")
> Cc: sta...@dpdk.org
>
> Signed-off-by: David Marchand <david.march...@redhat.com>
> ---
> lib/vhost/vhost_crypto.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/lib/vhost/vhost_crypto.c b/lib/vhost/vhost_crypto.c
> index b1c0eb6a0f..83325b7042 100644
> --- a/lib/vhost/vhost_crypto.c
> +++ b/lib/vhost/vhost_crypto.c
> @@ -576,16 +576,16 @@ copy_data(void *dst_data, struct vhost_crypto_data_req
> *vc_req,
> uint32_t to_copy;
> uint8_t *data = dst_data;
> uint8_t *src;
> - int left = size;
> + uint32_t left = size;
>
> - to_copy = RTE_MIN(desc->len, (uint32_t)left);
> + to_copy = RTE_MIN(desc->len, left);
> dlen = to_copy;
> src = IOVA_TO_VVA(uint8_t *, vc_req, desc->addr, &dlen,
> VHOST_ACCESS_RO);
Tracking the functions which end up being called by this macro, the dlen
parameter ends up being of type "uint64_t *", passing a value of int * or
uint32_t * seems wrong to me. If we are changing the type from int to
uint32_t, I think it should be promoted all the way to uint64_t.
> - if (unlikely(!src || !dlen))
> + if (unlikely(!src || !dlen || dlen > left))
> return -1;
>
If this change is omitted, does the compiler still give warnings. Looking
through the called code, the dlen parameter can only ever be reduced, not
incremented (function rte_vhost_va_from_guest_pa() in rte_vhost.h).
> - rte_memcpy((uint8_t *)data, src, dlen);
> + rte_memcpy(data, src, dlen);
> data += dlen;
>
> if (unlikely(dlen < to_copy)) {
> --
> 2.36.1
>
