2021-03-29 12:38:42

by Lv Yunlong

Subject: [PATCH] ethernet: myri10ge: Fix a use after free in myri10ge_sw_tso

In myri10ge_sw_tso, the skb_list_walk_safe macro will set
(curr) = (segs) and (next) = (curr)->next. If status!=0 is true,
the memory pointed by curr and segs will be free by dev_kfree_skb_any(curr).
But later, the segs is used by segs = segs->next and causes a uaf.

As (next) = (curr)->next, my patch replaces seg->next to next.

Fixes: 536577f36ff7a ("net: myri10ge: use skb_list_walk_safe helper for gso segments")
Signed-off-by: Lv Yunlong <[email protected]>
---
drivers/net/ethernet/myricom/myri10ge/myri10ge.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
index 1634ca6d4a8f..c84c8bf2bc20 100644
--- a/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
+++ b/drivers/net/ethernet/myricom/myri10ge/myri10ge.c
@@ -2897,7 +2897,7 @@ static netdev_tx_t myri10ge_sw_tso(struct sk_buff *skb,
dev_kfree_skb_any(curr);
if (segs != NULL) {
curr = segs;
- segs = segs->next;
+ segs = next;
curr->next = NULL;
dev_kfree_skb_any(segs);
}
--
2.25.1

2021-03-29 20:51:33

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] ethernet: myri10ge: Fix a use after free in myri10ge_sw_tso

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Mon, 29 Mar 2021 05:36:48 -0700 you wrote:
> In myri10ge_sw_tso, the skb_list_walk_safe macro will set
> (curr) = (segs) and (next) = (curr)->next. If status!=0 is true,
> the memory pointed by curr and segs will be free by dev_kfree_skb_any(curr).
> But later, the segs is used by segs = segs->next and causes a uaf.
>
> As (next) = (curr)->next, my patch replaces seg->next to next.
>
> [...]

Here is the summary with links:
- ethernet: myri10ge: Fix a use after free in myri10ge_sw_tso
https://git.kernel.org/netdev/net/c/63415767a244

You are awesome, thank you!
--
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