From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pdx-out-004.esa.us-west-2.outbound.mail-perimeter.amazon.com (pdx-out-004.esa.us-west-2.outbound.mail-perimeter.amazon.com [44.246.77.92]) (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 986C33F5BD8; Tue, 28 Jul 2026 20:57:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=44.246.77.92 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785272276; cv=none; b=ewii+JEJ7jod64sjcw7KPleIaeOSob5QGyc1gzjtiWvicAno70+MjsRbag4CSgftd34AR8bzwSozWZ8rtxrK/LwiVcxUzYNoOWJzEcan8SbnQtNacWE2qI0dKYstGHBcsAJnLlf2+5vkVOsaZqT7bRaIPN0mzaTyC9BfK9EWXkk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785272276; c=relaxed/simple; bh=ZvnPUWrNcaKvQBCRr4k2xw4gaX/UAV4Bgiv0oCYEFjU=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=P/A1SpXgfagsaeIe8RR2/wgmpiW47RBoIlznA5Mg5ISHWCx9MX43YAMaE7lC2aIIFDgYjTw0wgztD3FHFwQrvuk6zVtmwW0vH5wAZOZsuCVKO8fEHMOsLdqorbyxvhO3U0Eldl1/5HuoIKwbswgljmFKY6lWzLWNKgerggRMgBo= 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=qOONYc9P; arc=none smtp.client-ip=44.246.77.92 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="qOONYc9P" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1785272273; x=1816808273; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=J4MzSKA9lmF/CEAOgCFqoHzMp6jKD08xpbr1OHrrn1g=; b=qOONYc9Pgiq71tzBrZisa+7Un9Fei+dXZ41UKftchCg0+heHklRBnmcb 2NQKINWqHlz6Muv/1eOkpreD9oRGX4LadbHG7gCBYOLbgvFF90tBSszTC 6bTF5Dh0+oLnqsKT/+yyOY4mAqbczITNdK07uLbUs9D56qNpS87kbvIRW 68sJpE9YVmvp1TL9NOtsnQY/ZPK86f7rouuguFCjrGt3Dxd0SLX+HmLDC hxp6Mbd9gKrUExHbARid9TBcCRw+RdS/DqYySUcMEFzqAurzzOPCzswpD znZ/tmVKXmvn9Rl/UHW4E3Pakm7bD6FpYK6xsDVMQExxlsB8HS6u+iOWB w==; X-CSE-ConnectionGUID: CjX8MELRQHa+/K44WAhQKQ== X-CSE-MsgGUID: GDO5KOj9SPG1ffO4zGrMOw== X-IronPort-AV: E=Sophos;i="6.25,191,1779148800"; d="scan'208";a="24521913" Received: from ip-10-5-6-203.us-west-2.compute.internal (HELO smtpout.naws.us-west-2.prod.farcaster.email.amazon.dev) ([10.5.6.203]) by internal-pdx-out-004.esa.us-west-2.outbound.mail-perimeter.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Jul 2026 20:57:45 +0000 Received: from EX19MTAUWC002.ant.amazon.com [205.251.233.51:3446] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.56.7:2525] with esmtp (Farcaster) id 7190f09d-bc42-4076-8c0a-a9083cd9506d; Tue, 28 Jul 2026 20:57:45 +0000 (UTC) X-Farcaster-Flow-ID: 7190f09d-bc42-4076-8c0a-a9083cd9506d Received: from EX19D001UWA001.ant.amazon.com (10.13.138.214) by EX19MTAUWC002.ant.amazon.com (10.250.64.143) 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 20:57:44 +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 20:57:44 +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 v2] bpf: Fix same-register dst/src OOB read and pointer leak in sock_ops Date: Tue, 28 Jul 2026 20:57:44 +0000 Message-ID: <20260728205744.28301-1-wanjay@amazon.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260728203418.26079-1-wanjay@amazon.com> References: <20260728203418.26079-1-wanjay@amazon.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: EX19D042UWB002.ant.amazon.com (10.13.139.175) 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 --- v2: rebased onto v6.12.98 to resolve context conflict reported by CI 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 f54e7152d6879..90e396423eb7a 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -10483,10 +10483,11 @@ 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) @@ -10520,10 +10521,11 @@ 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