Re: [Qemu-devel] [PULL 10/28] Sanity check RDMA remote data

[Paolo Bonzini]

On 07/07/2015 15:08, Juan Quintela wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> Perform some basic (but probably not complete) sanity checking on
> requests from the RDMA source.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> Reviewed-by: Michael R. Hines <address@hidden>
> Signed-off-by: Juan Quintela <address@hidden>
> ---
>  migration/rdma.c | 30 ++++++++++++++++++++++++++++++
>  1 file changed, 30 insertions(+)
> 
> diff --git a/migration/rdma.c b/migration/rdma.c
> index 73844a3..73a79be 100644
> --- a/migration/rdma.c
> +++ b/migration/rdma.c
> @@ -2992,6 +2992,13 @@ static int qemu_rdma_registration_handle(QEMUFile *f, 
> void *opaque)
>              trace_qemu_rdma_registration_handle_compress(comp->length,
>                                                           comp->block_idx,
>                                                           comp->offset);
> +            if (comp->block_idx >= rdma->local_ram_blocks.nb_blocks) {
> +                error_report("rdma: 'compress' bad block index %u (vs %d)",
> +                             (unsigned int)comp->block_idx,
> +                             rdma->local_ram_blocks.nb_blocks);
> +                ret = -EIO;
> +                break;

Did you want "goto out" here, and especially inside the for loop below:

> +            }
>              block = &(rdma->local_ram_blocks.block[comp->block_idx]);
> 
>              host_addr = block->local_host_addr +
> @@ -3080,8 +3087,23 @@ static int qemu_rdma_registration_handle(QEMUFile *f, 
> void *opaque)
>                  trace_qemu_rdma_registration_handle_register_loop(count,
>                           reg->current_index, reg->key.current_addr, 
> reg->chunks);
> 
> +                if (reg->current_index >= rdma->local_ram_blocks.nb_blocks) {
> +                    error_report("rdma: 'register' bad block index %u (vs 
> %d)",
> +                                 (unsigned int)reg->current_index,
> +                                 rdma->local_ram_blocks.nb_blocks);
> +                    ret = -ENOENT;
> +                    break;

Here

> +                }
>                  block = &(rdma->local_ram_blocks.block[reg->current_index]);
>                  if (block->is_ram_block) {
> +                    if (block->offset > reg->key.current_addr) {
> +                        error_report("rdma: bad register address for block 
> %s"
> +                            " offset: %" PRIx64 " current_addr: %" PRIx64,
> +                            block->block_name, block->offset,
> +                            reg->key.current_addr);
> +                        ret = -ERANGE;
> +                        break;

here

> +                    }
>                      host_addr = (block->local_host_addr +
>                                  (reg->key.current_addr - block->offset));
>                      chunk = ram_chunk_index(block->local_host_addr,
> @@ -3090,6 +3112,14 @@ static int qemu_rdma_registration_handle(QEMUFile *f, 
> void *opaque)
>                      chunk = reg->key.chunk;
>                      host_addr = block->local_host_addr +
>                          (reg->key.chunk * (1UL << RDMA_REG_CHUNK_SHIFT));
> +                    /* Check for particularly bad chunk value */
> +                    if (host_addr < (void *)block->local_host_addr) {
> +                        error_report("rdma: bad chunk for block %s"
> +                            " chunk: %" PRIx64,
> +                            block->block_name, reg->key.chunk);
> +                        ret = -ERANGE;
> +                        break;

and here the "break" takes you directly to

   ret = qemu_rdma_post_send_control(rdma,
                            (uint8_t *) results, &reg_resp);

where ret is overwritten (spotted by Coverity).

Paolo


Paolo

> +                    }
>                  }
>                  chunk_start = ram_chunk_start(block, chunk);
>                  chunk_end = ram_chunk_end(block, chunk + reg->chunks);
>