From patchwork Wed Aug 21 09:30:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tze-nan Wu X-Patchwork-Id: 13771137 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 511B7C52D6F for ; Wed, 21 Aug 2024 09:33:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Owner; bh=7E84GIHXbOx7jBLbf+I8NSxdpVEuRrIuEkSs5jTJbGg=; b=UN7My75OEyhOcoUysfI6jCycCm NdZ0ynjBqZI0kEqTL4Og1aPZuYz9QtJYZFzBZOWzyy4C0M2GhByB2X/tdW0b+GVSt5nmhmMHORT1X WsLNEBbkMfNv5n5YIZRSq6sfoCW0LNTAJrsuV15Rf7ViDvMdiK2LsmJlGXWLPfWPeb6JPetumZCFx WU3WaQgEsiyhpitYunZjhuQPNuFGSLr1ow4OIkEd4ypxa9euA08RJyn7JrRK19L2sYMalGEyRXsmE PSZt535sPJAvLJbnTNXoOhMU859klbMtw1DEMLe+UE5NfdvrAZbUT9/9LeU51XFu0TN+ZrN/2mhYp z7KWJt7w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sghix-00000008GUR-4788; Wed, 21 Aug 2024 09:33:51 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sghgI-00000008FpX-443N; Wed, 21 Aug 2024 09:31:09 +0000 X-UUID: 163ab3ce5fa011efba0aef63c0775dbf-20240821 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=Content-Type:MIME-Version:Message-ID:Date:Subject:CC:To:From; bh=7E84GIHXbOx7jBLbf+I8NSxdpVEuRrIuEkSs5jTJbGg=; b=dY4mfA5SAWAH1wA7HHE+KmF880YigIByq+AX4F1np4lfA3bpf+gSbf11fNcfx215c6vJxHdoC8uv5eFPA1j4MzA+/WvrYxq4SBAm2wdgYZ1Zs+gVr/fFwRu++q6EjAEXG/cl6etgXNI089BuaSd2jEO6qso88nUFKgUh2NeMn+U=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.1.41,REQID:8a9925d9-1204-4662-b156-299c19851b64,IP:0,U RL:0,TC:0,Content:-5,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION :release,TS:-5 X-CID-META: VersionHash:6dc6a47,CLOUDID:09f1b3be-d7af-4351-93aa-42531abf0c7b,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:102,TC:nil,Content:0,EDM:-3,IP:nil,U RL:11|1,File:nil,RT:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0,OSA:0,AV:0,LES :1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 0,NGT X-CID-BAS: 0,NGT,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR,TF_CID_SPAM_ULN X-UUID: 163ab3ce5fa011efba0aef63c0775dbf-20240821 Received: from mtkmbs09n1.mediatek.inc [(172.21.101.35)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 401815040; Wed, 21 Aug 2024 02:31:04 -0700 Received: from mtkmbs11n1.mediatek.inc (172.21.101.185) by MTKMBS09N2.mediatek.inc (172.21.101.94) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.26; Wed, 21 Aug 2024 02:30:31 -0700 Received: from mtksdccf07.mediatek.inc (172.21.84.99) by mtkmbs11n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1118.26 via Frontend Transport; Wed, 21 Aug 2024 17:30:31 +0800 From: Tze-nan Wu To: , , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Matthias Brugger , AngeloGioacchino Del Regno , Stanislav Fomichev CC: , , , , Kuniyuki Iwashima , Tze-nan Wu , Yanghui Li , Cheng-Jui Wang , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Subject: [PATCH net v4] bpf, net: Check cgroup_bpf_enabled() only once in do_sock_getsockopt() Date: Wed, 21 Aug 2024 17:30:16 +0800 Message-ID: <20240821093016.2533-1-Tze-nan.Wu@mediatek.com> X-Mailer: git-send-email 2.18.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240821_023107_261343_BFACDF22 X-CRM114-Status: GOOD ( 16.46 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org The return value from `cgroup_bpf_enabled(CGROUP_GETSOCKOPT)` can change between the invocations of `BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN` and `BPF_CGROUP_RUN_PROG_GETSOCKOPT`. If `cgroup_bpf_enabled(CGROUP_GETSOCKOPT)` changes from "false" to "true" between the invocations of `BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN` and `BPF_CGROUP_RUN_PROG_GETSOCKOPT`, `BPF_CGROUP_RUN_PROG_GETSOCKOPT` will receive an -EFAULT from `__cgroup_bpf_run_filter_getsockopt(max_optlen=0)` due to `get_user()` was not reached in `BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN`. Scenario shown as below: `process A` `process B` ----------- ------------ BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN enable CGROUP_GETSOCKOPT BPF_CGROUP_RUN_PROG_GETSOCKOPT (-EFAULT) To prevent this, invoke `cgroup_bpf_enabled()` only once and cache the result in a newly added local variable `enabled`. Both `BPF_CGROUP_*` macros in `do_sock_getsockopt` will then check their condition using the same `enabled` variable as the condition variable, instead of using the return values from `cgroup_bpf_enabled` called by themselves as the condition variable(which could yield different results). This ensures that either both `BPF_CGROUP_*` macros pass the condition or neither does. Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") Co-developed-by: Yanghui Li Signed-off-by: Yanghui Li Co-developed-by: Cheng-Jui Wang Signed-off-by: Cheng-Jui Wang Signed-off-by: Tze-nan Wu --- Chagnes from v1 to v2: https://lore.kernel.org/all/20240819082513.27176-1-Tze-nan.Wu@mediatek.com/ Instead of using cgroup_lock in the fastpath, invoke cgroup_bpf_enabled only once and cache the value in the newly added variable `enabled`. `BPF_CGROUP_*` macros in do_sock_getsockopt can then both check their condition with the new variable `enable`, ensuring that either they both passing the condition or both do not. Chagnes from v2 to v3: https://lore.kernel.org/all/20240819155627.1367-1-Tze-nan.Wu@mediatek.com/ Hide cgroup_bpf_enabled in the macro, and some modifications to adapt the coding style. Chagnes from v3 to v4: https://lore.kernel.org/all/20240820092942.16654-1-Tze-nan.Wu@mediatek.com/ Add bpf tag to subject, and Fixes tag in body. --- include/linux/bpf-cgroup.h | 15 ++++++++------- net/socket.c | 5 +++-- 2 files changed, 11 insertions(+), 9 deletions(-) diff --git a/include/linux/bpf-cgroup.h b/include/linux/bpf-cgroup.h index fb3c3e7181e6..5afa2ac76aae 100644 --- a/include/linux/bpf-cgroup.h +++ b/include/linux/bpf-cgroup.h @@ -390,20 +390,20 @@ static inline bool cgroup_bpf_sock_enabled(struct sock *sk, __ret; \ }) -#define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen) \ +#define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen, enabled) \ ({ \ int __ret = 0; \ - if (cgroup_bpf_enabled(CGROUP_GETSOCKOPT)) \ + enabled = cgroup_bpf_enabled(CGROUP_GETSOCKOPT); \ + if (enabled) \ copy_from_sockptr(&__ret, optlen, sizeof(int)); \ __ret; \ }) #define BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock, level, optname, optval, optlen, \ - max_optlen, retval) \ + max_optlen, retval, enabled) \ ({ \ int __ret = retval; \ - if (cgroup_bpf_enabled(CGROUP_GETSOCKOPT) && \ - cgroup_bpf_sock_enabled(sock, CGROUP_GETSOCKOPT)) \ + if (enabled && cgroup_bpf_sock_enabled(sock, CGROUP_GETSOCKOPT)) \ if (!(sock)->sk_prot->bpf_bypass_getsockopt || \ !INDIRECT_CALL_INET_1((sock)->sk_prot->bpf_bypass_getsockopt, \ tcp_bpf_bypass_getsockopt, \ @@ -518,9 +518,10 @@ static inline int bpf_percpu_cgroup_storage_update(struct bpf_map *map, #define BPF_CGROUP_RUN_PROG_SOCK_OPS(sock_ops) ({ 0; }) #define BPF_CGROUP_RUN_PROG_DEVICE_CGROUP(atype, major, minor, access) ({ 0; }) #define BPF_CGROUP_RUN_PROG_SYSCTL(head,table,write,buf,count,pos) ({ 0; }) -#define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen) ({ 0; }) +#define BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen, enabled) ({ 0; }) #define BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock, level, optname, optval, \ - optlen, max_optlen, retval) ({ retval; }) + optlen, max_optlen, retval, \ + enabled) ({ retval; }) #define BPF_CGROUP_RUN_PROG_GETSOCKOPT_KERN(sock, level, optname, optval, \ optlen, retval) ({ retval; }) #define BPF_CGROUP_RUN_PROG_SETSOCKOPT(sock, level, optname, optval, optlen, \ diff --git a/net/socket.c b/net/socket.c index fcbdd5bc47ac..0b465dc8a789 100644 --- a/net/socket.c +++ b/net/socket.c @@ -2363,6 +2363,7 @@ int do_sock_getsockopt(struct socket *sock, bool compat, int level, int optname, sockptr_t optval, sockptr_t optlen) { int max_optlen __maybe_unused; + bool enabled __maybe_unused; const struct proto_ops *ops; int err; @@ -2371,7 +2372,7 @@ int do_sock_getsockopt(struct socket *sock, bool compat, int level, return err; if (!compat) - max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen); + max_optlen = BPF_CGROUP_GETSOCKOPT_MAX_OPTLEN(optlen, enabled); ops = READ_ONCE(sock->ops); if (level == SOL_SOCKET) { @@ -2390,7 +2391,7 @@ int do_sock_getsockopt(struct socket *sock, bool compat, int level, if (!compat) err = BPF_CGROUP_RUN_PROG_GETSOCKOPT(sock->sk, level, optname, optval, optlen, max_optlen, - err); + err, enabled); return err; }