[Swan-dev] [PATCH libreswan] netlink: Silence negative shift coverity false warning

[Antony Antony]

Hi Aviv,

thanks for trying to fix the issue. However, this patch introduce more 
problems.

netlink_esp_hw_offload =  UINT_MAX  or UINT_MAX-1
netlink_esp_hw_offload + 32 would overflow.

** CID 1455227:    (INTEGER_OVERFLOW)
/programs/pluto/kernel_netlink.c: 932 in netlink_detect_offload()
/programs/pluto/kernel_netlink.c: 924 in netlink_detect_offload()
/programs/pluto/kernel_netlink.c: 924 in netlink_detect_offload()

________________________________________________________________________________________________________
*** CID 1455227:    (INTEGER_OVERFLOW)
/programs/pluto/kernel_netlink.c: 932 in netlink_detect_offload()
926     
927     	cmd = alloc_bytes(sizeof(*cmd) + sizeof(cmd->features[0]) * blocks, "ethtool_gfeatures");
928     	jam_str(ifr.ifr_name, sizeof(ifr.ifr_name), ifname);
929     	ifr.ifr_data = (void *)cmd;
930     	cmd->cmd = ETHTOOL_GFEATURES;
931     	cmd->size = blocks;
>>>     CID 1455227:    (INTEGER_OVERFLOW)
>>>     Overflowed or truncated value (or a value computed from an overflowed or truncated value) "blocks - 1" used as array index.
932     	if ((ioctl(netlinkfd, SIOCETHTOOL, &ifr) == 0) &&
933     		(cmd->features[blocks-1].active & feature_bit))
934     		ret = IFNO_SUPPORTED;
935     
936     	pfree(cmd);
937     
/programs/pluto/kernel_netlink.c: 924 in netlink_detect_offload()
918     		netlink_find_offload_feature(ifname);
919     
920     	if (netlink_esp_hw_offload == NIC_OFFLOAD_UNSUPPORTED)
921     		return ret;
922     
923     	/* Feature is supported by kernel. Query device features */
>>>     CID 1455227:    (INTEGER_OVERFLOW)
>>>     Add operation overflows on operands "netlink_esp_hw_offload" and "31U".
924     	blocks = (netlink_esp_hw_offload + 31) / 32;
925     	feature_bit = 1 << (netlink_esp_hw_offload % 31);
926     
927     	cmd = alloc_bytes(sizeof(*cmd) + sizeof(cmd->features[0]) * blocks, "ethtool_gfeatures");
928     	jam_str(ifr.ifr_name, sizeof(ifr.ifr_name), ifname);
929     	ifr.ifr_data = (void *)cmd;
/programs/pluto/kernel_netlink.c: 924 in netlink_detect_offload()
918     		netlink_find_offload_feature(ifname);
919     
920     	if (netlink_esp_hw_offload == NIC_OFFLOAD_UNSUPPORTED)
921     		return ret;
922     
923     	/* Feature is supported by kernel. Query device features */
>>>     CID 1455227:    (INTEGER_OVERFLOW)
>>>     Add operation overflows on operands "netlink_esp_hw_offload" and "31U".
924     	blocks = (netlink_esp_hw_offload + 31) / 32;
925     	feature_bit = 1 << (netlink_esp_hw_offload % 31);
926     
927     	cmd = alloc_bytes(sizeof(*cmd) + sizeof(cmd->features[0]) * blocks, "ethtool_gfeatures");
928     	jam_str(ifr.ifr_name, sizeof(ifr.ifr_name), ifname);
929     	ifr.ifr_data = (void *)cmd;


On Thu, Aug 31, 2017 at 06:24:07PM +0300, avivh at mellanox.com wrote:
> From: Aviv Heller <avivh at mellanox.com>
> 
> Use an unsigned type instead.
> 
> Signed-off-by: Aviv Heller <avivh at mellanox.com>
> ---
>  programs/pluto/kernel_netlink.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/programs/pluto/kernel_netlink.c b/programs/pluto/kernel_netlink.c
> index b12d19b..c8f7bfd 100644
> --- a/programs/pluto/kernel_netlink.c
> +++ b/programs/pluto/kernel_netlink.c
> @@ -96,14 +96,14 @@
>  /* Minimum priority number in SPD used by pluto. */
>  #define MIN_SPD_PRIORITY 1024
>  
> -#define NIC_OFFLOAD_UNKNOWN (-2)
> -#define NIC_OFFLOAD_UNSUPPORTED (-1)
> +#define NIC_OFFLOAD_UNKNOWN     (UINT_MAX)
> +#define NIC_OFFLOAD_UNSUPPORTED (UINT_MAX - 1)
>  
>  static int netlinkfd = NULL_FD;
>  static int netlink_bcast_fd = NULL_FD;
>  
>  #ifdef USE_NIC_OFFLOAD
> -static int netlink_esp_hw_offload = NIC_OFFLOAD_UNKNOWN;
> +static unsigned int netlink_esp_hw_offload = NIC_OFFLOAD_UNKNOWN;
>  #endif
>  
>  #define NE(x) { x, #x }	/* Name Entry -- shorthand for sparse_names */
> -- 
> 1.8.3.1
> 
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