From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A82E23644A4 for ; Tue, 28 Apr 2026 20:53:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777409637; cv=none; b=ZKNiuHiDdLuf0Ax6H+IXrdEvEMEyjSKdYvAk8vKsPGA0S6yaNNfdEMApt8iwPALoXBAfWgUX+pmAVaXNlgpARBYrdCeEA/2U3SOBbKK5Qzs00zjQEB2S1H22w0bz81RG6YWqJWvVRCJDjMsVj1Cf65TMrmRA1GmZ02dpQxoD8zs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777409637; c=relaxed/simple; bh=IB6CLdot/1t2KBAZHoMsvVQS75ShQpHfi3cvDKVXg8c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=e5APh2xgX4WVXOws41abvlKzpqCQ0Vfb8pjA5czYhp4o/nkcLr5+ZfJZFCk5njLzSZjmb6M5EipAWQOQfmme0Ww3xQZH76cI/A5JoiMULAw6C5S9NUa+rDBv0x+deQJ53DVH5Pd7tfXgTF529kNXT4OpY8BLOvAtzbAC3DTvaME= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g+LLoKfj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g+LLoKfj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D251C2BCB7; Tue, 28 Apr 2026 20:53:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777409637; bh=IB6CLdot/1t2KBAZHoMsvVQS75ShQpHfi3cvDKVXg8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g+LLoKfj0uIPQlYKXzTGuFfklaVN0PRo/5UCSAVaLOc0UHd0y/vHS9oQC01VFuTJT Xxm9TVGBX/gasSt+NnPaHlDzYAukcyQKdqTdRfHiOhkyoNA6eD2d3H6fobWfzQ1C8p 2PW6OIfFKaSwFiNQPLA/Ya4k1vrShK3cjhtWEmLK7obXG9jdWHiJZHFP8+caFGmPla vPN8Uh/cOwZky8UjviAC8wttlF/nK3S/xrSCYiSnozfDp/U1GH9Iyebw9CRL0VO+Ru LqtzxDwRpusm8RXkSxFhX/CPTn6W57TA/R7YVCXVqUVCmAv9kCO3ifcwZbEafTlN9b n32xNpXVe0B9w== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, willemdebruijn.kernel@gmail.com, daniel.zahka@gmail.com, Jakub Kicinski Subject: [PATCH net-next 1/3] psp: validate protocol before mutating skb in psp_dev_encapsulate() Date: Tue, 28 Apr 2026 13:53:50 -0700 Message-ID: <20260428205352.1247325-2-kuba@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260428205352.1247325-1-kuba@kernel.org> References: <20260428205352.1247325-1-kuba@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Code checkers / AI scans will complain that we have already modified the packet by the time we realize that protocol is not IP. Move the skb->protocol check to before skb_push()/memmove() so that the skb is not left in a corrupted state when the function returns false for an unsupported protocol. psp_dev_rcv() follows similar pattern. Today this path is unreachable because both in-tree callers (mlx5 and netdevsim) only reach psp_dev_encapsulate() from TCP socket TX paths where skb->protocol is always ETH_P_IP or ETH_P_IPV6, and both drop the skb on a false return, anyway. Signed-off-by: Jakub Kicinski --- net/psp/psp_main.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/psp/psp_main.c b/net/psp/psp_main.c index 9508b6c38003..652ec8a9c8a4 100644 --- a/net/psp/psp_main.c +++ b/net/psp/psp_main.c @@ -228,6 +228,10 @@ bool psp_dev_encapsulate(struct net *net, struct sk_buff *skb, __be32 spi, u32 ethr_len = skb_mac_header_len(skb); u32 bufflen = ethr_len + network_len; + if (skb->protocol != htons(ETH_P_IP) && + skb->protocol != htons(ETH_P_IPV6)) + return false; + if (skb_cow_head(skb, PSP_ENCAP_HLEN)) return false; @@ -243,11 +247,9 @@ bool psp_dev_encapsulate(struct net *net, struct sk_buff *skb, __be32 spi, ip_hdr(skb)->check = 0; ip_hdr(skb)->check = ip_fast_csum((u8 *)ip_hdr(skb), ip_hdr(skb)->ihl); - } else if (skb->protocol == htons(ETH_P_IPV6)) { + } else { ipv6_hdr(skb)->nexthdr = IPPROTO_UDP; be16_add_cpu(&ipv6_hdr(skb)->payload_len, PSP_ENCAP_HLEN); - } else { - return false; } skb_set_inner_ipproto(skb, IPPROTO_TCP); -- 2.54.0