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 5C8131170E for ; Mon, 11 Sep 2023 14:25:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D1A3AC433C7; Mon, 11 Sep 2023 14:25:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694442334; bh=zuNmQ6UHjatW9oYeG8PxCkn4RXqtsJddeYXaSggcsBA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Jb4O5p5VRpL2iR5d7LsjRs9QsZap1Jpdyz+GQRRd+IDX+6p54jEB3TwtDKJuW0IkT HrhigV2ybV5KlXpf6IpWFxb/xT6PA3Jc4joXAmixKRolmU+/RgkVvAXjZG/sFjc5gi qKHTs0QTpyWAsY+Fpaq59ACArNdcoiIQOGof0gbM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jann Horn , Kuniyuki Iwashima , "David S. Miller" Subject: [PATCH 6.5 700/739] dccp: Fix out of bounds access in DCCP error handler Date: Mon, 11 Sep 2023 15:48:19 +0200 Message-ID: <20230911134710.643567892@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230911134650.921299741@linuxfoundation.org> References: <20230911134650.921299741@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jann Horn commit 977ad86c2a1bcaf58f01ab98df5cc145083c489c upstream. There was a previous attempt to fix an out-of-bounds access in the DCCP error handlers, but that fix assumed that the error handlers only want to access the first 8 bytes of the DCCP header. Actually, they also look at the DCCP sequence number, which is stored beyond 8 bytes, so an explicit pskb_may_pull() is required. Fixes: 6706a97fec96 ("dccp: fix out of bound access in dccp_v4_err()") Fixes: 1aa9d1a0e7ee ("ipv6: dccp: fix out of bound access in dccp_v6_err()") Cc: stable@vger.kernel.org Signed-off-by: Jann Horn Reviewed-by: Kuniyuki Iwashima Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/dccp/ipv4.c | 13 +++++++++---- net/dccp/ipv6.c | 15 ++++++++++----- 2 files changed, 19 insertions(+), 9 deletions(-) --- a/net/dccp/ipv4.c +++ b/net/dccp/ipv4.c @@ -255,12 +255,17 @@ static int dccp_v4_err(struct sk_buff *s int err; struct net *net = dev_net(skb->dev); - /* Only need dccph_dport & dccph_sport which are the first - * 4 bytes in dccp header. + /* For the first __dccp_basic_hdr_len() check, we only need dh->dccph_x, + * which is in byte 7 of the dccp header. * Our caller (icmp_socket_deliver()) already pulled 8 bytes for us. + * + * Later on, we want to access the sequence number fields, which are + * beyond 8 bytes, so we have to pskb_may_pull() ourselves. */ - BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8); - BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8); + dh = (struct dccp_hdr *)(skb->data + offset); + if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh))) + return -EINVAL; + iph = (struct iphdr *)skb->data; dh = (struct dccp_hdr *)(skb->data + offset); sk = __inet_lookup_established(net, &dccp_hashinfo, --- a/net/dccp/ipv6.c +++ b/net/dccp/ipv6.c @@ -74,7 +74,7 @@ static inline __u64 dccp_v6_init_sequenc static int dccp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, u8 type, u8 code, int offset, __be32 info) { - const struct ipv6hdr *hdr = (const struct ipv6hdr *)skb->data; + const struct ipv6hdr *hdr; const struct dccp_hdr *dh; struct dccp_sock *dp; struct ipv6_pinfo *np; @@ -83,12 +83,17 @@ static int dccp_v6_err(struct sk_buff *s __u64 seq; struct net *net = dev_net(skb->dev); - /* Only need dccph_dport & dccph_sport which are the first - * 4 bytes in dccp header. + /* For the first __dccp_basic_hdr_len() check, we only need dh->dccph_x, + * which is in byte 7 of the dccp header. * Our caller (icmpv6_notify()) already pulled 8 bytes for us. + * + * Later on, we want to access the sequence number fields, which are + * beyond 8 bytes, so we have to pskb_may_pull() ourselves. */ - BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_sport) > 8); - BUILD_BUG_ON(offsetofend(struct dccp_hdr, dccph_dport) > 8); + dh = (struct dccp_hdr *)(skb->data + offset); + if (!pskb_may_pull(skb, offset + __dccp_basic_hdr_len(dh))) + return -EINVAL; + hdr = (const struct ipv6hdr *)skb->data; dh = (struct dccp_hdr *)(skb->data + offset); sk = __inet6_lookup_established(net, &dccp_hashinfo,