[PATCH v3] myri10ge: fix an incorrect free for skb in myri10ge_sw_tso

[PATCH v3] myri10ge: fix an incorrect free for skb in myri10ge_sw_tso

[Xiaomeng Tong]

All remaining skbs should be released when myri10ge_xmit fails to
transmit a packet. Fix it within another skb_list_walk_safe.

Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---

changes since v2:
 - free all remaining skbs. (Xiaomeng Tong)

changes since v1:
 - remove the unneeded assignmnets. (Xiaomeng Tong)

v2:https://lore.kernel.org/lkml/20220405000553.21856-1-xiam0nd.tong@gmail.com/
v1:https://lore.kernel.org/lkml/20220319052350.26535-1-xiam0nd.tong@gmail.com/

---
 drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 50ac3ee2577a..21d2645885ce 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -2903,11 +2903,9 @@ static netdev_tx_t myri10ge_sw_tso(struct sk_buff *skb,
 		status = myri10ge_xmit(curr, dev);
 		if (status != 0) {
 			dev_kfree_skb_any(curr);
-			if (segs != NULL) {
-				curr = segs;
-				segs = next;
+			skb_list_walk_safe(next, curr, next) {
 				curr->next = NULL;
-				dev_kfree_skb_any(segs);
+				dev_kfree_skb_any(curr);
 			}
 			goto drop;
 		}
-- 
2.17.1

Re: [PATCH v3] myri10ge: fix an incorrect free for skb in myri10ge_sw_tso

[Denis Kirjanov]

4/6/22 06:55, Xiaomeng Tong пишет:
> All remaining skbs should be released when myri10ge_xmit fails to
> transmit a packet. Fix it within another skb_list_walk_safe.
> 
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
> ---
> 
> changes since v2:
>   - free all remaining skbs. (Xiaomeng Tong)
> 
> changes since v1:
>   - remove the unneeded assignmnets. (Xiaomeng Tong)
> 
> v2:https://lore.kernel.org/lkml/20220405000553.21856-1-xiam0nd.tong@gmail.com/
> v1:https://lore.kernel.org/lkml/20220319052350.26535-1-xiam0nd.tong@gmail.com/
> 
> ---
>   drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> index 50ac3ee2577a..21d2645885ce 100644
> --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> @@ -2903,11 +2903,9 @@ static netdev_tx_t myri10ge_sw_tso(struct sk_buff *skb,
>   		status = myri10ge_xmit(curr, dev);
>   		if (status != 0) {
a transmit function returns NETDEV_TX_OK on success
>   			dev_kfree_skb_any(curr);
> -			if (segs != NULL) {
> -				curr = segs;
> -				segs = next;
> +			skb_list_walk_safe(next, curr, next) {
>   				curr->next = NULL;
> -				dev_kfree_skb_any(segs);
> +				dev_kfree_skb_any(curr);
>   			}
>   			goto drop;
>   		}

Re: [PATCH v3] myri10ge: fix an incorrect free for skb in myri10ge_sw_tso

[Denis Kirjanov]

4/6/22 06:55, Xiaomeng Tong пишет:
> All remaining skbs should be released when myri10ge_xmit fails to
> transmit a packet. Fix it within another skb_list_walk_safe.
> 
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
> ---
> 
> changes since v2:
>   - free all remaining skbs. (Xiaomeng Tong)
> 
> changes since v1:
>   - remove the unneeded assignmnets. (Xiaomeng Tong)
> 
> v2:https://lore.kernel.org/lkml/20220405000553.21856-1-xiam0nd.tong@gmail.com/
> v1:https://lore.kernel.org/lkml/20220319052350.26535-1-xiam0nd.tong@gmail.com/
> 
> ---
>   drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 6 ++----
>   1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> index 50ac3ee2577a..21d2645885ce 100644
> --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> @@ -2903,11 +2903,9 @@ static netdev_tx_t myri10ge_sw_tso(struct sk_buff *skb,
>   		status = myri10ge_xmit(curr, dev);
>   		if (status != 0) {
>   			dev_kfree_skb_any(curr);
> -			if (segs != NULL) {
> -				curr = segs;
> -				segs = next;
> +			skb_list_walk_safe(next, curr, next) {
>   				curr->next = NULL;
> -				dev_kfree_skb_any(segs);
> +				dev_kfree_skb_any(curr);

why can't we just do the following?
         skb_list_walk_safe(segs, skb, nskb) {
                 status = myri10ge_xmit(curr, dev);
                 if (err)
                         break;

         }

         /* Free all of the segments. */
         skb_list_walk_safe(segs, skb, nskb) {
                 if (err)
                         kfree_skb(skb);
                 else
                         consume_skb(skb);
         }
         return err;


>   			}
>   			goto drop;
>   		}

Re: [PATCH v3] myri10ge: fix an incorrect free for skb in myri10ge_sw_tso

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Wed,  6 Apr 2022 11:55:56 +0800 you wrote:
> All remaining skbs should be released when myri10ge_xmit fails to
> transmit a packet. Fix it within another skb_list_walk_safe.
> 
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
> ---
> 
> changes since v2:
>  - free all remaining skbs. (Xiaomeng Tong)
> 
> [...]

Here is the summary with links:
  - [v3] myri10ge: fix an incorrect free for skb in myri10ge_sw_tso
    https://git.kernel.org/netdev/net/c/b423e54ba965

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH v3] myri10ge: fix an incorrect free for skb in myri10ge_sw_tso

[Jakub Kicinski]

On Wed,  6 Apr 2022 11:55:56 +0800 Xiaomeng Tong wrote:
> All remaining skbs should be released when myri10ge_xmit fails to
> transmit a packet. Fix it within another skb_list_walk_safe.

I think it was also a UAF.

> diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> index 50ac3ee2577a..21d2645885ce 100644
> --- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> +++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
> @@ -2903,11 +2903,9 @@ static netdev_tx_t myri10ge_sw_tso(struct sk_buff *skb,
>  		status = myri10ge_xmit(curr, dev);
>  		if (status != 0) {
>  			dev_kfree_skb_any(curr);
> -			if (segs != NULL) {
> -				curr = segs;
> -				segs = next;
> +			skb_list_walk_safe(next, curr, next) {
>  				curr->next = NULL;
> -				dev_kfree_skb_any(segs);
> +				dev_kfree_skb_any(curr);
>  			}
>  			goto drop;
>  		}

Much better, thanks. 

kfree_skb_list() exists but the patch was already applied, so whatever.