From 74d6529b78f7a440a10aa7f4904ca9f27d1d2f3c Mon Sep 17 00:00:00 2001 From: Heng Qi Date: Fri, 28 Jun 2024 12:40:18 +0800 Subject: [PATCH] net: ethtool: Fix the panic caused by dev being null when dumping coalesce syzbot reported a general protection fault caused by a null pointer dereference in coalesce_fill_reply(). The issue occurs when req_base->dev is null, leading to an invalid memory access. This panic occurs if dumping coalesce when no device name is specified. Fixes: f750dfe825b9 ("ethtool: provide customized dim profile management") Reported-by: syzbot+e77327e34cdc8c36b7d3@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=e77327e34cdc8c36b7d3 Signed-off-by: Heng Qi Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- net/ethtool/coalesce.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ethtool/coalesce.c b/net/ethtool/coalesce.c index 759b16e3d1342..3e18ca1ccc5ef 100644 --- a/net/ethtool/coalesce.c +++ b/net/ethtool/coalesce.c @@ -211,9 +211,9 @@ static int coalesce_fill_reply(struct sk_buff *skb, { const struct coalesce_reply_data *data = COALESCE_REPDATA(reply_base); const struct kernel_ethtool_coalesce *kcoal = &data->kernel_coalesce; - struct dim_irq_moder *moder = req_base->dev->irq_moder; const struct ethtool_coalesce *coal = &data->coalesce; u32 supported = data->supported_params; + struct dim_irq_moder *moder; int ret = 0; if (coalesce_put_u32(skb, ETHTOOL_A_COALESCE_RX_USECS, @@ -272,9 +272,10 @@ static int coalesce_fill_reply(struct sk_buff *skb, kcoal->tx_aggr_time_usecs, supported)) return -EMSGSIZE; - if (!moder) + if (!req_base->dev || !req_base->dev->irq_moder) return 0; + moder = req_base->dev->irq_moder; rcu_read_lock(); if (moder->profile_flags & DIM_PROFILE_RX) { ret = coalesce_put_profile(skb, ETHTOOL_A_COALESCE_RX_PROFILE, -- 2.39.5