Re: [dpdk-dev] [PATCH v3] net/bonding: fix potential out of bounds read

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 4/17/2019 3:36 PM, Radu Nicolau wrote:
> Add validation to pointer constructed from the IPv4 header length
> in order to prevent malformed packets from generating a potential
> out of bounds memory read.
> 
> Fixes: 09150784a776 ("net/bonding: burst mode hash calculation")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Radu Nicolau <radu.nicolau@intel.com>

Hi Chas,

Do you have any objection on the patch?
Functionally looks correct to me, but additional checks in datapath perhaps can
be a concern, if not I am for getting the patch.

> ---
> v2: add fixes lines
> v3: fix buffer end calculation
> 
>  drivers/net/bonding/rte_eth_bond_pmd.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/bonding/rte_eth_bond_pmd.c b/drivers/net/bonding/rte_eth_bond_pmd.c
> index b0d191d..2b7f2b3 100644
> --- a/drivers/net/bonding/rte_eth_bond_pmd.c
> +++ b/drivers/net/bonding/rte_eth_bond_pmd.c
> @@ -842,6 +842,7 @@ burst_xmit_l34_hash(struct rte_mbuf **buf, uint16_t nb_pkts,
>  
>  	for (i = 0; i < nb_pkts; i++) {
>  		eth_hdr = rte_pktmbuf_mtod(buf[i], struct ether_hdr *);
> +		size_t pkt_end = (size_t)eth_hdr + rte_pktmbuf_data_len(buf[i]);
>  		proto = eth_hdr->ether_type;
>  		vlan_offset = get_vlan_offset(eth_hdr, &proto);
>  		l3hash = 0;
> @@ -865,13 +866,17 @@ burst_xmit_l34_hash(struct rte_mbuf **buf, uint16_t nb_pkts,
>  					tcp_hdr = (struct tcp_hdr *)
>  						((char *)ipv4_hdr +
>  							ip_hdr_offset);
> -					l4hash = HASH_L4_PORTS(tcp_hdr);
> +					if ((size_t)tcp_hdr + sizeof(*tcp_hdr)
> +							< pkt_end)
> +						l4hash = HASH_L4_PORTS(tcp_hdr);
>  				} else if (ipv4_hdr->next_proto_id ==
>  								IPPROTO_UDP) {
>  					udp_hdr = (struct udp_hdr *)
>  						((char *)ipv4_hdr +
>  							ip_hdr_offset);
> -					l4hash = HASH_L4_PORTS(udp_hdr);
> +					if ((size_t)udp_hdr + sizeof(*udp_hdr)
> +							< pkt_end)
> +						l4hash = HASH_L4_PORTS(udp_hdr);
>  				}
>  			}
>  		} else if  (rte_cpu_to_be_16(ETHER_TYPE_IPv6) == proto) {
>