From: Matt Johnston Date: Thu, 6 Mar 2025 02:33:20 +0000 (+0800) Subject: net: mctp i2c: Copy headers if cloned X-Git-Tag: v6.14-rc7~27^2~20 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=df8ce77ba8b7c012a3edd1ca7368b46831341466;p=linux-block.git net: mctp i2c: Copy headers if cloned Use skb_cow_head() prior to modifying the TX SKB. This is necessary when the SKB has been cloned, to avoid modifying other shared clones. Signed-off-by: Matt Johnston Fixes: f5b8abf9fc3d ("mctp i2c: MCTP I2C binding driver") Link: https://patch.msgid.link/20250306-matt-mctp-i2c-cow-v1-1-293827212681@codeconstruct.com.au Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/mctp/mctp-i2c.c b/drivers/net/mctp/mctp-i2c.c index e3dcdeacc12c..d74d47dd6e04 100644 --- a/drivers/net/mctp/mctp-i2c.c +++ b/drivers/net/mctp/mctp-i2c.c @@ -583,6 +583,7 @@ static int mctp_i2c_header_create(struct sk_buff *skb, struct net_device *dev, struct mctp_i2c_hdr *hdr; struct mctp_hdr *mhdr; u8 lldst, llsrc; + int rc; if (len > MCTP_I2C_MAXMTU) return -EMSGSIZE; @@ -593,6 +594,10 @@ static int mctp_i2c_header_create(struct sk_buff *skb, struct net_device *dev, lldst = *((u8 *)daddr); llsrc = *((u8 *)saddr); + rc = skb_cow_head(skb, sizeof(struct mctp_i2c_hdr)); + if (rc) + return rc; + skb_push(skb, sizeof(struct mctp_i2c_hdr)); skb_reset_mac_header(skb); hdr = (void *)skb_mac_header(skb);