From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794373525; b=OabbH321IKkaT+5pKFmsJexOuiPdzFfJkqAlVgbI3cc+nyqJ8SKy1IVnIdYaO47EyZ21 Xlft4CDIJCipupDwzaakWfd98PjWSGoPfIl4ZfeFgTESnAcuIy0HlcXdalOhsRlTf4HLI RP9l5Y8VRKLiFoNWmIF3qUMhZKeaE/dwyQlqYKOnSivN3bp+iepwTDfGDGcUaTY10//I7 d3I27pFr1xnQHnW5loQMoAu2e0JZ3whvPmCeFNieQw67PRYjMrvZ2BWqRDKpYCgH5Xdbd h2PfKStVpBKvR719U8kNWClVCo8p5q2FPVkSAhSy+M95HXDU8wkcxLm9Z75PTG6hdcg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794373525; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=E0EZdtxPL/bhjGsKtZICWUrXhhzOOD8llovzkCj0O8c=; b=jhlAa49jdRlUo1M7mJQcMeVqlSV1HHRfDJsW/7rRDCiGNOv/5RMFfhvV5bEsBUklfZAH QcF3ZzPbExq09T5LTf8QSWNaLe012g/yfF/zH483bMPKUuaBRiWQhkA/N7HC8/2HTlI8Z gtGW/UIvSPyrRs4YaW1VTT72UQMwj8nZsEVWpmHFapcQi4msKrpb0C0Zf3/qYXtTEIc5O 4hPUgdqS9e1glXYjGOL3qySYI4YszpFsYhZ/B8j4448amoxVdQSRbTzWNFJzoKBBbu905 x0NAXsCovuDnTsBEbcSZ5etx1lzb04aPHpjmsbas2oFXKMQq1QPCx1lgoMDNp4OdhpQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=jWRDmMHJ; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 55AA7606A31C for ; Wed, 11 Nov 2026 05:05:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=jWRDmMHJ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56F751F0089F; Wed, 11 Nov 2026 05:05:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794373525; bh=E0EZdtxPL/bhjGsKtZICWUrXhhzOOD8llovzkCj0O8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jWRDmMHJwB4f40bCJUcgYtCy7NB8VQlXnRk8N0TelzMrjvIdudEZfHYnYRTKnY62Y /wJfPqIl82W5ISnQrzWidJuvtrhuZZZRhVovdrzRblYLnktDTvIsBqHldQJ++L9e/C vUR2DrZMzad92F/1K9VLW2EpQjcHM9D+V8hkfpT7BK9Eo3+dBjnFhxgwDW3YvGEsaQ Ek02xVlrVbeGoSQH/+jEBE76gTQKiknRQ0cpnYr7GuPmgmB0G+X5d/3KJ+tBui0uzu 3NOQVcJxIOugotkFJhrfCTgP2OmHhuo5P8yWuuqY0CkIqHKHCWMi83+c3VZJ1Bg63h JqxQhVBC/iGaw== From: Sasha Levin To: stable@vger.kernel.org Cc: Ido Schimmel , Sashiko , Hangbin Liu , Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1.y 3/3] ipmr, ip6mr: validate packets injected into the register vif on xmit Date: Wed, 11 Nov 2026 00:05:21 -0500 Message-ID: <20261111050514.1221320-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261111050514.1221320-1-sashal@kernel.org> References: <20261107055529-failed-6.1-aa1799e93f5e@kernel.org> <20261111050514.1221320-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ido Schimmel [ Upstream commit aa1799e93f5ebb973252aec649d84d12d9c7fd1c ] reg_vif_xmit() passes the packet to ipmr_cache_report() which copies its IP header into the IGMPMSG_WHOLEPKT report that is queued to the mroute socket. Nothing guarantees that the packet contains a full IP header, so when a short packet is injected on the register device (e.g., using AF_PACKET), the copy reads past the end of the packet and a recvmsg() on the mroute socket leaks the uninitialized bytes to user space [1]. IPv6 has the same problem [2]. Its reg_vif_xmit() does call pskb_inet_may_pull(), but the helper keys off skb->protocol and does not pull anything when the protocol is neither IPv4 nor IPv6. Fix by dropping packets whose protocol does not match the address family of the register device or that do not contain a full network header. [1] BUG: KMSAN: kernel-infoleak in _copy_to_iter raw_recvmsg Uninit was stored to memory at: ipmr_cache_report reg_vif_xmit packet_sendmsg Uninit was created at: __alloc_skb sock_alloc_send_pskb packet_sendmsg Bytes 1-3 of 21 are uninitialized [2] BUG: KMSAN: kernel-infoleak in _copy_to_iter rawv6_recvmsg Uninit was stored to memory at: ip6mr_cache_report reg_vif_xmit packet_sendmsg Uninit was created at: __alloc_skb sock_alloc_send_pskb packet_sendmsg Bytes 8-23 of 41 are uninitialized Fixes: 14fb64e1f449 ("[IPV6] MROUTE: Support PIM-SM (SSM).") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Reported-by: Sashiko Closes: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/0545f0c83f5ee2f6696210f87268e811ef655715.1792476357.git.zhilinz%40nebusec.ai Signed-off-by: Ido Schimmel Reviewed-by: Hangbin Liu Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20261025071729.34967-3-idosch@nvidia.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv4/ipmr.c | 6 ++++++ net/ipv6/ip6mr.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index d93e57c31b6aa..2f9c39b3cb5aa 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -512,6 +512,12 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb, struct net_device *dev) }; int err; + if (skb->protocol != htons(ETH_P_IP) || !pskb_inet_may_pull(skb)) { + DEV_STATS_INC(dev, tx_errors); + kfree_skb(skb); + return NETDEV_TX_OK; + } + rcu_read_lock(); err = ipmr_fib_lookup(net, &fl4, &mrt); if (err < 0) { diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index b677f48179c87..362e670fe7f7e 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -616,7 +616,7 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb, .flowi6_mark = skb->mark, }; - if (!pskb_inet_may_pull(skb)) + if (skb->protocol != htons(ETH_P_IPV6) || !pskb_inet_may_pull(skb)) goto tx_err; if (ip6mr_fib_lookup(net, &fl6, &mrt) < 0) -- 2.53.0