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From: subashab@codeaurora.org
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Sean Tranchetti <stranche@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH net-next] net: qualcomm: rmnet: fix two pointer math bugs
Date: Sat, 19 Jun 2021 13:12:09 -0600	[thread overview]
Message-ID: <027ae9e2ddc18f0ed30c5d9c7075c8b9@codeaurora.org> (raw)
In-Reply-To: <YM32lkJIJdSgpR87@mwanda>

On 2021-06-19 07:52, Dan Carpenter wrote:
> We recently changed these two pointers from void pointers to struct
> pointers and it breaks the pointer math so now the "txphdr" points
> beyond the end of the buffer.
> 
> Fixes: 56a967c4f7e5 ("net: qualcomm: rmnet: Remove some unneeded 
> casts")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
>  drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> index 3ee5c1a8b46e..3676976c875b 100644
> --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c
> @@ -168,7 +168,7 @@ static void
> rmnet_map_complement_ipv4_txporthdr_csum_field(struct iphdr *ip4h)
>  	void *txphdr;
>  	u16 *csum;
> 
> -	txphdr = ip4h + ip4h->ihl * 4;
> +	txphdr = (void *)ip4h + ip4h->ihl * 4;
> 
>  	if (ip4h->protocol == IPPROTO_TCP || ip4h->protocol == IPPROTO_UDP) {
>  		csum = (u16 *)rmnet_map_get_csum_field(ip4h->protocol, txphdr);
> @@ -203,7 +203,7 @@
> rmnet_map_complement_ipv6_txporthdr_csum_field(struct ipv6hdr *ip6h)
>  	void *txphdr;
>  	u16 *csum;
> 
> -	txphdr = ip6h + sizeof(struct ipv6hdr);
> +	txphdr = ip6h + 1;
> 
>  	if (ip6h->nexthdr == IPPROTO_TCP || ip6h->nexthdr == IPPROTO_UDP) {
>  		csum = (u16 *)rmnet_map_get_csum_field(ip6h->nexthdr, txphdr);

Hi Dan

Thanks for fixing this. Could you cast the ip4h to char* instead of 
void*.
Looks like gcc might raise issues if -Wpointer-arith is used.

https://gcc.gnu.org/onlinedocs/gcc-4.5.0/gcc/Pointer-Arith.html#Pointer-Arith

  reply	other threads:[~2021-06-19 19:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-19 13:52 [PATCH net-next] net: qualcomm: rmnet: fix two pointer math bugs Dan Carpenter
2021-06-19 19:12 ` subashab [this message]
2021-06-21  7:11   ` Dan Carpenter
2021-06-21  7:18     ` Dan Carpenter
2021-06-21 16:44       ` subashab
2021-06-21 19:30 ` patchwork-bot+netdevbpf

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