From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pdx-out-014.esa.us-west-2.outbound.mail-perimeter.amazon.com (pdx-out-014.esa.us-west-2.outbound.mail-perimeter.amazon.com [35.83.148.184]) (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 DDD792EEE90; Tue, 28 Jul 2026 20:34:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=35.83.148.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785270862; cv=none; b=KUlMOWPP4OnH/cFPHFF1am6qbF9Yp1eESi1S6YC9XnYaHuG4FQxLIIRpwtYBW6dwx3l6Dh5TN7ozsekIztD8ppD1HW6Djxb5SflPO8ZYQoNzDuup7fZ7zg3v3uiv9cEN4CVKvwJJ+KrLGsPoOjqEH7eBzAfCx0zPvxUX0gbVLZg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785270862; c=relaxed/simple; bh=iMynQQeOcSHJktJ6RxML+z4ykMmb7RE+eAa8IkDzUD0=; h=From:To:CC:Subject:Date:Message-ID:MIME-Version:Content-Type; b=lJ5vWwO8eJVWgw6uUte8nb03qAfZqTGHW/yFEJ+TPr+7PmvJZswLMP5EEjfm93NvBKxVIXA8gD/Zpx5dDMOLG33CtFxHa7EX+FwsbLca46xxvezjYbicuGAGi31Zt4RotR3V5IicNbCAjbj2ICyQazdbgIKbcvVZolr6gvfubwQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=YMbcho14; arc=none smtp.client-ip=35.83.148.184 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="YMbcho14" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1785270860; x=1816806860; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=NbHYsikM/I/p8dp73VL8XWAfmndZWKcW9lyNqHzg6T4=; b=YMbcho14TKDbLDy693MDk6PEcLyN4kzCcBMCUj/zv+XR51yZmLeCL3to T6zeyPz0ULAGUXdSHYzIn2AjA03FKBgnj9eGPdMf0Mv8reVp2fBkU/h1E IATwoCCjaW/49d3EHsxZ/lbK+nBYKZPVmHBAvNW7w7HHRDbN30olgdMbA KDOzWNe+wEf5bNkYGOpfqbxvdvC4ij3QAspCUPPIGKyHLaFzqnO040325 Yce1U4mIBzpbbo3t9hzjj0jYJ70bhoX0iqq03IOypVXbb4SE8P52+9Qcy Bp7LcgWjSy/gWv8UBYP6mk0kAYqKvEnnWFaAdfXsuDo7sLnsMKZM8zml4 A==; X-CSE-ConnectionGUID: UgMXxCcjTlyiLt1p93c6Ww== X-CSE-MsgGUID: Q56Zj4nrRjeW256eF14Bxw== X-IronPort-AV: E=Sophos;i="6.25,191,1779148800"; d="scan'208";a="24314889" Received: from ip-10-5-12-219.us-west-2.compute.internal (HELO smtpout.naws.us-west-2.prod.farcaster.email.amazon.dev) ([10.5.12.219]) by internal-pdx-out-014.esa.us-west-2.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jul 2026 20:34:20 +0000 Received: from EX19MTAUWB001.ant.amazon.com [205.251.233.104:22192] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.25.115:2525] with esmtp (Farcaster) id 55988a16-4ccc-4b48-a703-a1ce85c65631; Tue, 28 Jul 2026 20:34:20 +0000 (UTC) X-Farcaster-Flow-ID: 55988a16-4ccc-4b48-a703-a1ce85c65631 Received: from EX19D001UWA001.ant.amazon.com (10.13.138.214) by EX19MTAUWB001.ant.amazon.com (10.250.64.248) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.45; Tue, 28 Jul 2026 20:34:20 +0000 Received: from dev-dsk-wanjay-2c-d25651b4.us-west-2.amazon.com (172.19.198.4) by EX19D001UWA001.ant.amazon.com (10.13.138.214) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.2562.45; Tue, 28 Jul 2026 20:34:19 +0000 From: Jay Wang To: CC: , , , , , Quan Sun <2022090917019@std.uestc.edu.cn>, Yinhao Hu , Kaiyan Mei , Dongliang Mu , "Emil Tsalapatis" , Jakub Kicinski Subject: [PATCH 6.12.y] bpf: Fix same-register dst/src OOB read and pointer leak in sock_ops Date: Tue, 28 Jul 2026 20:34:18 +0000 Message-ID: <20260728203418.26079-1-wanjay@amazon.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: EX19D044UWA002.ant.amazon.com (10.13.139.11) To EX19D001UWA001.ant.amazon.com (10.13.138.214) From: Jiayuan Chen [ Upstream commit 10f86a2a5c91fc4c4d001960f1c21abe52545ef6 ] When a BPF sock_ops program accesses ctx fields with dst_reg == src_reg, the SOCK_OPS_GET_SK() and SOCK_OPS_GET_FIELD() macros fail to zero the destination register in the !fullsock / !locked_tcp_sock path. Both macros borrow a temporary register to check is_fullsock / is_locked_tcp_sock when dst_reg == src_reg, because dst_reg holds the ctx pointer. When the check is false (e.g., TCP_NEW_SYN_RECV state with a request_sock), dst_reg should be zeroed but is not, leaving the stale ctx pointer: - SOCK_OPS_GET_SK: dst_reg retains the ctx pointer, passes NULL checks as PTR_TO_SOCKET_OR_NULL, and can be used as a bogus socket pointer, leading to stack-out-of-bounds access in helpers like bpf_skc_to_tcp6_sock(). - SOCK_OPS_GET_FIELD: dst_reg retains the ctx pointer which the verifier believes is a SCALAR_VALUE, leaking a kernel pointer. Fix both macros by: - Changing JMP_A(1) to JMP_A(2) in the fullsock path to skip the added instruction. - Adding BPF_MOV64_IMM(si->dst_reg, 0) after the temp register restore in the !fullsock path, placed after the restore because dst_reg == src_reg means we need src_reg intact to read ctx->temp. Fixes: fd09af010788 ("bpf: sock_ops ctx access may stomp registers in corner case") Fixes: 84f44df664e9 ("bpf: sock_ops sk access may stomp registers when dst_reg = src_reg") Reported-by: Quan Sun <2022090917019@std.uestc.edu.cn> Reported-by: Yinhao Hu Reported-by: Kaiyan Mei Reported-by: Dongliang Mu Reviewed-by: Emil Tsalapatis Closes: https://lore.kernel.org/bpf/6fe1243e-149b-4d3b-99c7-fcc9e2f75787@std.uestc.edu.cn/T/#u Signed-off-by: Jiayuan Chen Acked-by: Martin KaFai Lau Link: https://patch.msgid.link/20260407022720.162151-2-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin Signed-off-by: Jay Wang --- net/core/filter.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index b03621405d062..609a97237b424 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -10467,10 +10467,11 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, si->dst_reg, si->dst_reg, \ offsetof(OBJ, OBJ_FIELD)); \ if (si->dst_reg == si->src_reg) { \ - *insn++ = BPF_JMP_A(1); \ + *insn++ = BPF_JMP_A(2); \ *insn++ = BPF_LDX_MEM(BPF_DW, reg, si->src_reg, \ offsetof(struct bpf_sock_ops_kern, \ temp)); \ + *insn++ = BPF_MOV64_IMM(si->dst_reg, 0); \ } \ } while (0) @@ -10504,10 +10505,11 @@ static u32 sock_ops_convert_ctx_access(enum bpf_access_type type, si->dst_reg, si->src_reg, \ offsetof(struct bpf_sock_ops_kern, sk));\ if (si->dst_reg == si->src_reg) { \ - *insn++ = BPF_JMP_A(1); \ + *insn++ = BPF_JMP_A(2); \ *insn++ = BPF_LDX_MEM(BPF_DW, reg, si->src_reg, \ offsetof(struct bpf_sock_ops_kern, \ temp)); \ + *insn++ = BPF_MOV64_IMM(si->dst_reg, 0); \ } \ } while (0) -- 2.47.3