Messages in this thread Patch in this message | | | Date | Thu, 16 Jan 2020 11:30:44 +0800 | From | Gen Zhang <> | Subject | [PATCH] driver: tg3: fix potential UAF in tigon3_dma_hwbug_workaround() |
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In tigon3_dma_hwbug_workaround(), pskb is first stored in skb. And this function is to store new_skb into pskb at the end. However, in the error paths when new_skb is freed by dev_kfree_skb_any(), stroing new_skb to pskb should be prevented.
And freeing skb with dev_consume_skb_any() should be executed after storing new_skb to pskb, because freeing skb will free pskb (alias).
Signed-off-by: Gen Zhang <blackgod016574@gmail.com> --- diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c index ca3aa12..dbfac26 100644 --- a/drivers/net/ethernet/broadcom/tg3.c +++ b/drivers/net/ethernet/broadcom/tg3.c @@ -7826,6 +7826,7 @@ static int tigon3_dma_hwbug_workaround(struct tg3_napi *tnapi, if (!new_skb) { ret = -1; + goto new_skb_err; } else { /* New SKB is guaranteed to be linear. */ new_addr = pci_map_single(tp->pdev, new_skb->data, new_skb->len, @@ -7834,6 +7835,7 @@ static int tigon3_dma_hwbug_workaround(struct tg3_napi *tnapi, if (pci_dma_mapping_error(tp->pdev, new_addr)) { dev_kfree_skb_any(new_skb); ret = -1; + goto new_skb_err; } else { u32 save_entry = *entry; @@ -7849,12 +7851,14 @@ static int tigon3_dma_hwbug_workaround(struct tg3_napi *tnapi, tg3_tx_skb_unmap(tnapi, save_entry, -1); dev_kfree_skb_any(new_skb); ret = -1; + goto new_skb_err; } } } - dev_consume_skb_any(skb); *pskb = new_skb; + dev_consume_skb_any(skb); +new_skb_err: return ret; }
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