From 32afa1f23e42cc635ccf4c39f24514d03d1e8338 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 21 Sep 2022 13:10:05 -0700 Subject: [PATCH] bnxt: prevent skb UAF after handing over to PTP worker [ Upstream commit c31f26c8f69f776759cbbdfb38e40ea91aa0dd65 ] When reading the timestamp is required bnxt_tx_int() hands over the ownership of the completed skb to the PTP worker. The skb should not be used afterwards, as the worker may run before the rest of our code and free the skb, leading to a use-after-free. Since dev_kfree_skb_any() accepts NULL make the loss of ownership more obvious and set skb to NULL. Fixes: 83bb623c968e ("bnxt_en: Transmit and retrieve packet timestamps") Reviewed-by: Andy Gospodarek Reviewed-by: Michael Chan Link: https://lore.kernel.org/r/20220921201005.335390-1-kuba@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 964354536f9c..111a952f880e 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -662,7 +662,6 @@ static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) for (i = 0; i < nr_pkts; i++) { struct bnxt_sw_tx_bd *tx_buf; - bool compl_deferred = false; struct sk_buff *skb; int j, last; @@ -671,6 +670,8 @@ static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) skb = tx_buf->skb; tx_buf->skb = NULL; + tx_bytes += skb->len; + if (tx_buf->is_push) { tx_buf->is_push = 0; goto next_tx_int; @@ -691,8 +692,9 @@ static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) } if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)) { if (bp->flags & BNXT_FLAG_CHIP_P5) { + /* PTP worker takes ownership of the skb */ if (!bnxt_get_tx_ts_p5(bp, skb)) - compl_deferred = true; + skb = NULL; else atomic_inc(&bp->ptp_cfg->tx_avail); } @@ -701,9 +703,7 @@ static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int nr_pkts) next_tx_int: cons = NEXT_TX(cons); - tx_bytes += skb->len; - if (!compl_deferred) - dev_kfree_skb_any(skb); + dev_kfree_skb_any(skb); } netdev_tx_completed_queue(txq, nr_pkts, tx_bytes); -- 2.45.0