From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-171.mta1.migadu.com (out-171.mta1.migadu.com [95.215.58.171]) (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 2F37B19CC2A for ; Wed, 15 Jan 2025 21:48:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736977729; cv=none; b=PNTWNj3Uz9NQlDeP2wp1AtwpvkGazuf8tvtz841b5bHEO0CNT724i1mQO4wAR9XpfEqbjX56tkshAkgkuNNAFQzv4QF4pUEk6Ffnq6VFU/aNg3fAjnwkLVh1/X03TpzLXvWn7T68s+fvxIw91cg0qcnD5SK0LAds/cihHkAeiBw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736977729; c=relaxed/simple; bh=eNjDr+kbc/7tm2nrjTg/UAoANKa+ssxWp9ac77aL1a0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=S//0HooSd5K1PlN2rUf0GFm0t1p6nqepLMfl0c0AkxaEorecCSUs2tgmAOYH7eKjCA0ejGGjZM/LkFruF6NLEhB5lHGt6UsmW8XSuvam/mZ1zPFYElrrRcMy8Rau4YRXIwhWWYpbFOCzGWXvFvZmVYtCStW/4YJjqLi0urYoDWY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=YG6Ujs69; arc=none smtp.client-ip=95.215.58.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="YG6Ujs69" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1736977725; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=52cb4GS2ZhRvjZmzSdZ0gUccl71Kegjj/jwbIqe2zTI=; b=YG6Ujs69KB38n0dMWzf+hWivnRcJm7Oc1f0FPikImV8gSO0fYhO1B2ipdTeoG/H+9RDc2c QblbG9Ca7lj/IcDibi8KRxyqspNqmurcvPUEX20JmhVm9eQUJeoEgeleR55zwp7KxuDGgS yf+l9tmr5NGO/YHbsPuY8O+Y7i20iEs= Date: Wed, 15 Jan 2025 13:48:37 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH net-next v5 05/15] net-timestamp: add strict check in some BPF calls To: Jason Xing Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, willemdebruijn.kernel@gmail.com, willemb@google.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, horms@kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org References: <20250112113748.73504-1-kerneljasonxing@gmail.com> <20250112113748.73504-6-kerneljasonxing@gmail.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau Content-Language: en-US In-Reply-To: <20250112113748.73504-6-kerneljasonxing@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 1/12/25 3:37 AM, Jason Xing wrote: > In the next round, we will support the UDP proto for SO_TIMESTAMPING > bpf extension, so we need to ensure there is no safety problem. > > Signed-off-by: Jason Xing > --- > net/core/filter.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/net/core/filter.c b/net/core/filter.c > index 0e915268db5f..517f09aabc92 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -5571,7 +5571,7 @@ static int __bpf_getsockopt(struct sock *sk, int level, int optname, > static int _bpf_getsockopt(struct sock *sk, int level, int optname, > char *optval, int optlen) > { > - if (sk_fullsock(sk)) > + if (sk_fullsock(sk) && optname != SK_BPF_CB_FLAGS) > sock_owned_by_me(sk); > return __bpf_getsockopt(sk, level, optname, optval, optlen); > } > @@ -5776,6 +5776,7 @@ BPF_CALL_5(bpf_sock_ops_getsockopt, struct bpf_sock_ops_kern *, bpf_sock, > int, level, int, optname, char *, optval, int, optlen) > { > if (IS_ENABLED(CONFIG_INET) && level == SOL_TCP && > + bpf_sock->sk->sk_protocol == IPPROTO_TCP && > optname >= TCP_BPF_SYN && optname <= TCP_BPF_SYN_MAC) { > int ret, copy_len = 0; > const u8 *start; > @@ -5817,7 +5818,8 @@ BPF_CALL_2(bpf_sock_ops_cb_flags_set, struct bpf_sock_ops_kern *, bpf_sock, > struct sock *sk = bpf_sock->sk; > int val = argval & BPF_SOCK_OPS_ALL_CB_FLAGS; > > - if (!IS_ENABLED(CONFIG_INET) || !sk_fullsock(sk)) > + if (!IS_ENABLED(CONFIG_INET) || !sk_fullsock(sk) || > + sk->sk_protocol != IPPROTO_TCP) > return -EINVAL; > > tcp_sk(sk)->bpf_sock_ops_cb_flags = val; > @@ -7626,6 +7628,9 @@ BPF_CALL_4(bpf_sock_ops_load_hdr_opt, struct bpf_sock_ops_kern *, bpf_sock, > u8 search_kind, search_len, copy_len, magic_len; > int ret; > > + if (bpf_sock->op != SK_BPF_CB_FLAGS) SK_BPF_CB_FLAGS is not an op enum, so the check is incorrect. It does break the existing test. ./test_progs -t tcp_hdr_options WARNING! Selftests relying on bpf_testmod.ko will be skipped. #402/1 tcp_hdr_options/simple_estab:FAIL #402/2 tcp_hdr_options/no_exprm_estab:FAIL #402/3 tcp_hdr_options/syncookie_estab:FAIL #402/4 tcp_hdr_options/fastopen_estab:FAIL #402/5 tcp_hdr_options/fin:FAIL #402/6 tcp_hdr_options/misc:FAIL #402 tcp_hdr_options:FAIL #402/1 tcp_hdr_options/simple_estab:FAIL #402/2 tcp_hdr_options/no_exprm_estab:FAIL #402/3 tcp_hdr_options/syncookie_estab:FAIL #402/4 tcp_hdr_options/fastopen_estab:FAIL #402/5 tcp_hdr_options/fin:FAIL #402/6 tcp_hdr_options/misc:FAIL #402 tcp_hdr_options:FAIL Many changes of this set is in bpf and the newly added selftest is also a bpf prog, all bpf selftests should be run before posting. (Documentation/bpf/bpf_devel_QA.rst) The bpf CI can automatically pick it up and get an auto email on breakage like this if the set is tagged to bpf-next. We can figure out where to land the set later (bpf-next/net or net-next/main) when it is ready. All these changes also need a test in selftests/bpf. For example, I expect there is a test to ensure calling these bpf helpers from the new tstamp callback will get a negative errno value. For patch 4 and patch 5, I would suggest keeping it simple to only check for bpf_sock->op for the helpers that make tcp_sock and/or locked sk assumption. Something like this on top of your patch. Untested: diff --git i/net/core/filter.c w/net/core/filter.c index 517f09aabc92..ccb13b61c528 100644 --- i/net/core/filter.c +++ w/net/core/filter.c @@ -7620,6 +7620,11 @@ static const u8 *bpf_search_tcp_opt(const u8 *op, const u8 *opend, return ERR_PTR(-ENOMSG); } +static bool is_locked_tcp_sock_ops(struct bpf_sock_ops_kern *bpf_sock) +{ + return bpf_sock->op <= BPF_SOCK_OPS_WRITE_HDR_OPT_CB; +} + BPF_CALL_4(bpf_sock_ops_load_hdr_opt, struct bpf_sock_ops_kern *, bpf_sock, void *, search_res, u32, len, u64, flags) { @@ -7628,8 +7633,8 @@ BPF_CALL_4(bpf_sock_ops_load_hdr_opt, struct bpf_sock_ops_kern *, bpf_sock, u8 search_kind, search_len, copy_len, magic_len; int ret; - if (bpf_sock->op != SK_BPF_CB_FLAGS) - return -EINVAL; + if (!is_locked_tcp_sock_ops(bpf_sock)) + return -EOPNOTSUPP; /* 2 byte is the minimal option len except TCPOPT_NOP and * TCPOPT_EOL which are useless for the bpf prog to learn > + return -EINVAL; > + > /* 2 byte is the minimal option len except TCPOPT_NOP and > * TCPOPT_EOL which are useless for the bpf prog to learn > * and this helper disallow loading them also.