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 3758618E374; Mon, 28 Oct 2024 06:38:19 +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=1730097499; cv=none; b=O7emVqpGhci8RsiP8oi+gSDepy/rvzJ4l5O7fLOYG5qSD0rWImiNu2J+FJYjKeYpjcHs2ZmPN736uUhHlymdFQmEiAMDdOAOqeLTYNjtEh/pz5EapTffiV9wWPivi49k4+vqhTMoW20S3r2uHFUHH1+gM88lGaZo7YcbJoQHYNk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730097499; c=relaxed/simple; bh=tGr4qsS/XOn/TOXMaNb/T/yeeA4CNxaLlF0BOyy7IuI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Pw4R5wPSr+aX4mVsjGDtXhwGKGa314CvjyUMAk5m7o91bjaoEKwxEnfqbIyu7KWMkkqAywe5J8NY6eqRH3iI1sc0j1JelyRodFl1D8V/DDFGhFZKM1gvmUsFIKfgKQVthArGzFlVlxVFcPAAc4UBsHv3nlk3H88IscWml5L/raA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DRxSUyk5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="DRxSUyk5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CCE5BC4CEC3; Mon, 28 Oct 2024 06:38:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730097499; bh=tGr4qsS/XOn/TOXMaNb/T/yeeA4CNxaLlF0BOyy7IuI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DRxSUyk5N37vq1267LKCVci76sVlOBrMCnBwciT8iGWkcLEEZzmUnH0r4cH2XvhGm XoXYlRX3UIuNLaSwWDprUK3ma7edS7H34vEjYQM2nNqZncPmzC6xkgXLcFZyR66Quk CMfAj0Wc7exp38YCCgjZ/Q/qq2aHET/uEc1QkDdk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+cca39e6e84a367a7e6f6@syzkaller.appspotmail.com, =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= , Daniel Borkmann , Sasha Levin Subject: [PATCH 6.6 002/208] bpf: Make sure internal and UAPI bpf_redirect flags dont overlap Date: Mon, 28 Oct 2024 07:23:02 +0100 Message-ID: <20241028062306.711918489@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241028062306.649733554@linuxfoundation.org> References: <20241028062306.649733554@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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Toke Høiland-Jørgensen [ Upstream commit 09d88791c7cd888d5195c84733caf9183dcfbd16 ] The bpf_redirect_info is shared between the SKB and XDP redirect paths, and the two paths use the same numeric flag values in the ri->flags field (specifically, BPF_F_BROADCAST == BPF_F_NEXTHOP). This means that if skb bpf_redirect_neigh() is used with a non-NULL params argument and, subsequently, an XDP redirect is performed using the same bpf_redirect_info struct, the XDP path will get confused and end up crashing, which syzbot managed to trigger. With the stack-allocated bpf_redirect_info, the structure is no longer shared between the SKB and XDP paths, so the crash doesn't happen anymore. However, different code paths using identically-numbered flag values in the same struct field still seems like a bit of a mess, so this patch cleans that up by moving the flag definitions together and redefining the three flags in BPF_F_REDIRECT_INTERNAL to not overlap with the flags used for XDP. It also adds a BUILD_BUG_ON() check to make sure the overlap is not re-introduced by mistake. Fixes: e624d4ed4aa8 ("xdp: Extend xdp_redirect_map with broadcast support") Reported-by: syzbot+cca39e6e84a367a7e6f6@syzkaller.appspotmail.com Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: Daniel Borkmann Acked-by: Daniel Borkmann Closes: https://syzkaller.appspot.com/bug?extid=cca39e6e84a367a7e6f6 Link: https://lore.kernel.org/bpf/20240920125625.59465-1-toke@redhat.com Signed-off-by: Sasha Levin --- include/uapi/linux/bpf.h | 13 +++++-------- net/core/filter.c | 8 +++++--- 2 files changed, 10 insertions(+), 11 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index ba6e346c8d669..4bb38409b26ad 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -5921,11 +5921,6 @@ enum { BPF_F_MARK_ENFORCE = (1ULL << 6), }; -/* BPF_FUNC_clone_redirect and BPF_FUNC_redirect flags. */ -enum { - BPF_F_INGRESS = (1ULL << 0), -}; - /* BPF_FUNC_skb_set_tunnel_key and BPF_FUNC_skb_get_tunnel_key flags. */ enum { BPF_F_TUNINFO_IPV6 = (1ULL << 0), @@ -6072,10 +6067,12 @@ enum { BPF_F_BPRM_SECUREEXEC = (1ULL << 0), }; -/* Flags for bpf_redirect_map helper */ +/* Flags for bpf_redirect and bpf_redirect_map helpers */ enum { - BPF_F_BROADCAST = (1ULL << 3), - BPF_F_EXCLUDE_INGRESS = (1ULL << 4), + BPF_F_INGRESS = (1ULL << 0), /* used for skb path */ + BPF_F_BROADCAST = (1ULL << 3), /* used for XDP path */ + BPF_F_EXCLUDE_INGRESS = (1ULL << 4), /* used for XDP path */ +#define BPF_F_REDIRECT_FLAGS (BPF_F_INGRESS | BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS) }; #define __bpf_md_ptr(type, name) \ diff --git a/net/core/filter.c b/net/core/filter.c index 8bfd46a070c16..bbb1432488430 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2423,9 +2423,9 @@ static int __bpf_redirect_neigh(struct sk_buff *skb, struct net_device *dev, /* Internal, non-exposed redirect flags. */ enum { - BPF_F_NEIGH = (1ULL << 1), - BPF_F_PEER = (1ULL << 2), - BPF_F_NEXTHOP = (1ULL << 3), + BPF_F_NEIGH = (1ULL << 16), + BPF_F_PEER = (1ULL << 17), + BPF_F_NEXTHOP = (1ULL << 18), #define BPF_F_REDIRECT_INTERNAL (BPF_F_NEIGH | BPF_F_PEER | BPF_F_NEXTHOP) }; @@ -2435,6 +2435,8 @@ BPF_CALL_3(bpf_clone_redirect, struct sk_buff *, skb, u32, ifindex, u64, flags) struct sk_buff *clone; int ret; + BUILD_BUG_ON(BPF_F_REDIRECT_INTERNAL & BPF_F_REDIRECT_FLAGS); + if (unlikely(flags & (~(BPF_F_INGRESS) | BPF_F_REDIRECT_INTERNAL))) return -EINVAL; -- 2.43.0