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 38B941D0174; Wed, 2 Oct 2024 13:35:33 +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=1727876133; cv=none; b=mj2iPeC/H9nyJ7Gw8SNlDnAwQLr9i7B3Yz+1CNNIPNrMdw/mWrJ6+LbnDRGiijU4NLk0QbuXJ/qzC2vKmJEvqPgLobf4nPv6WryEe6wio5pY4/XG/N5pkq413hkGBZpKP0GvAwT/J3BlZy0UJUjf8bhyVyWtsORHSvnJMKVHVeI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727876133; c=relaxed/simple; bh=QgOugubzsmkyR/8LuE6fx5M4ipSXYViZIVca9Sib3tg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eHHvOby8Nye83/V3nfl++kvVLgw1fCQPQC4KBE3RprzTPHju20hs8eQ5O43oJqPyi7j8BxKvHSPMSsl/nKGiP8fUSkhyL90aWDDr84b1tK4cKVhgNouHvkw1zGQDBGA7/9h6uN00hpZTX54pmZtj3WAYx2tK9YiQT9SbiMKeRlE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=prvI655j; 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="prvI655j" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B574BC4CEC5; Wed, 2 Oct 2024 13:35:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1727876133; bh=QgOugubzsmkyR/8LuE6fx5M4ipSXYViZIVca9Sib3tg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=prvI655jJS4xG3zJiQU6LPOr3OzoBhzAmQpM+5+OY0q0MjuSChTv7VHaZEed7Qzri 2qURfdix7n4wEUtGtbrxrf3G5OhMd3o+8SMCWN3Ej9cN6Z41ETQm1l406bxH0X7rBr QBrrs/OjACLUhWhAIP+Tgb3TDbNSvkuS8+xbcsS8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Daniel Borkmann , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.11 322/695] bpf: Zero former ARG_PTR_TO_{LONG,INT} args in case of error Date: Wed, 2 Oct 2024 14:55:20 +0200 Message-ID: <20241002125835.302692009@linuxfoundation.org> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241002125822.467776898@linuxfoundation.org> References: <20241002125822.467776898@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 6.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit 4b3786a6c5397dc220b1483d8e2f4867743e966f ] For all non-tracing helpers which formerly had ARG_PTR_TO_{LONG,INT} as input arguments, zero the value for the case of an error as otherwise it could leak memory. For tracing, it is not needed given CAP_PERFMON can already read all kernel memory anyway hence bpf_get_func_arg() and bpf_get_func_ret() is skipped in here. Also, the MTU helpers mtu_len pointer value is being written but also read. Technically, the MEM_UNINIT should not be there in order to always force init. Removing MEM_UNINIT needs more verifier rework though: MEM_UNINIT right now implies two things actually: i) write into memory, ii) memory does not have to be initialized. If we lift MEM_UNINIT, it then becomes: i) read into memory, ii) memory must be initialized. This means that for bpf_*_check_mtu() we're readding the issue we're trying to fix, that is, it would then be able to write back into things like .rodata BPF maps. Follow-up work will rework the MEM_UNINIT semantics such that the intent can be better expressed. For now just clear the *mtu_len on error path which can be lifted later again. Fixes: 8a67f2de9b1d ("bpf: expose bpf_strtol and bpf_strtoul to all program types") Fixes: d7a4cb9b6705 ("bpf: Introduce bpf_strtol and bpf_strtoul helpers") Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/e5edd241-59e7-5e39-0ee5-a51e31b6840a@iogearbox.net Link: https://lore.kernel.org/r/20240913191754.13290-5-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/helpers.c | 2 ++ kernel/bpf/syscall.c | 1 + net/core/filter.c | 44 +++++++++++++++++++++++--------------------- 3 files changed, 26 insertions(+), 21 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index b305b116ce125..c9e235807caca 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -522,6 +522,7 @@ BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags, long long _res; int err; + *res = 0; err = __bpf_strtoll(buf, buf_len, flags, &_res); if (err < 0) return err; @@ -549,6 +550,7 @@ BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags, bool is_negative; int err; + *res = 0; err = __bpf_strtoull(buf, buf_len, flags, &_res, &is_negative); if (err < 0) return err; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index efb7ff89fe2e2..d9cae8e259699 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -5932,6 +5932,7 @@ static const struct bpf_func_proto bpf_sys_close_proto = { BPF_CALL_4(bpf_kallsyms_lookup_name, const char *, name, int, name_sz, int, flags, u64 *, res) { + *res = 0; if (flags) return -EINVAL; diff --git a/net/core/filter.c b/net/core/filter.c index 88588dae20267..0e719c7c43bb7 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6262,20 +6262,25 @@ BPF_CALL_5(bpf_skb_check_mtu, struct sk_buff *, skb, int ret = BPF_MTU_CHK_RET_FRAG_NEEDED; struct net_device *dev = skb->dev; int skb_len, dev_len; - int mtu; + int mtu = 0; - if (unlikely(flags & ~(BPF_MTU_CHK_SEGS))) - return -EINVAL; + if (unlikely(flags & ~(BPF_MTU_CHK_SEGS))) { + ret = -EINVAL; + goto out; + } - if (unlikely(flags & BPF_MTU_CHK_SEGS && (len_diff || *mtu_len))) - return -EINVAL; + if (unlikely(flags & BPF_MTU_CHK_SEGS && (len_diff || *mtu_len))) { + ret = -EINVAL; + goto out; + } dev = __dev_via_ifindex(dev, ifindex); - if (unlikely(!dev)) - return -ENODEV; + if (unlikely(!dev)) { + ret = -ENODEV; + goto out; + } mtu = READ_ONCE(dev->mtu); - dev_len = mtu + dev->hard_header_len; /* If set use *mtu_len as input, L3 as iph->tot_len (like fib_lookup) */ @@ -6293,15 +6298,12 @@ BPF_CALL_5(bpf_skb_check_mtu, struct sk_buff *, skb, */ if (skb_is_gso(skb)) { ret = BPF_MTU_CHK_RET_SUCCESS; - if (flags & BPF_MTU_CHK_SEGS && !skb_gso_validate_network_len(skb, mtu)) ret = BPF_MTU_CHK_RET_SEGS_TOOBIG; } out: - /* BPF verifier guarantees valid pointer */ *mtu_len = mtu; - return ret; } @@ -6311,19 +6313,21 @@ BPF_CALL_5(bpf_xdp_check_mtu, struct xdp_buff *, xdp, struct net_device *dev = xdp->rxq->dev; int xdp_len = xdp->data_end - xdp->data; int ret = BPF_MTU_CHK_RET_SUCCESS; - int mtu, dev_len; + int mtu = 0, dev_len; /* XDP variant doesn't support multi-buffer segment check (yet) */ - if (unlikely(flags)) - return -EINVAL; + if (unlikely(flags)) { + ret = -EINVAL; + goto out; + } dev = __dev_via_ifindex(dev, ifindex); - if (unlikely(!dev)) - return -ENODEV; + if (unlikely(!dev)) { + ret = -ENODEV; + goto out; + } mtu = READ_ONCE(dev->mtu); - - /* Add L2-header as dev MTU is L3 size */ dev_len = mtu + dev->hard_header_len; /* Use *mtu_len as input, L3 as iph->tot_len (like fib_lookup) */ @@ -6333,10 +6337,8 @@ BPF_CALL_5(bpf_xdp_check_mtu, struct xdp_buff *, xdp, xdp_len += len_diff; /* minus result pass check */ if (xdp_len > dev_len) ret = BPF_MTU_CHK_RET_FRAG_NEEDED; - - /* BPF verifier guarantees valid pointer */ +out: *mtu_len = mtu; - return ret; } -- 2.43.0