From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CDF94471257; Tue, 21 Jul 2026 19:31:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784662278; cv=none; b=B7S7GGH9y4IbpkghLjVwH90jaQ9l138k7joXqDp3sMDR7Ll/edE24qz1Vf9KbK87gGSc0EBggMnXWn3DCE92AN0l3mJUN4zBTuGpNamHndlvvPSpNs6mi2Q18g088HrhAd4H8u6n8u6of1Pcn4Q28hLnLkap5BBvV1iCiXrGfPQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784662278; c=relaxed/simple; bh=j+InEzLg2OW5AhOASfatWDNI2Sueenk6AbMQiTKKGLI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=THtl+a6rTiNHmPhWgsBwg3aTtK1UOnS2VskRZNHihp8aopPXrvAtnEVUov1AP2vSkCKJhbX/IWnGFPUQryowkqnotd288LpvK9z6vtuqUSrrpSXKf56MMSxje90JfQ18Vk2qP+owjN22JYlWa1HLHnYPN0GscL9dxqwIkRPCQPM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=W2FUB1BH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="W2FUB1BH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 443271F000E9; Tue, 21 Jul 2026 19:31:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784662277; bh=6P90ZlUnyueaaRRLIpYJTZGbHxXrycbPp00g+BSirpQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=W2FUB1BH460rd4JJfaGYxDOO8TVM4rCAl6V0H0QNtDZaoH8WM9yiB1mljJLQ+tXht 3YRV1VkFOtjF9ApjPK6BBDLnRiPc2W4UFPjCBjveSm8HI4XxtEAJw9KVDKDrpe+fOI T50f+EfB72GbA9scJyOOAqY/575ZeBAzJH0LoPh8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayuan Chen , Emil Tsalapatis , Kuniyuki Iwashima , Sechang Lim , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.12 0385/1276] bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check Date: Tue, 21 Jul 2026 17:13:48 +0200 Message-ID: <20260721152454.722325863@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152446.065700225@linuxfoundation.org> References: <20260721152446.065700225@linuxfoundation.org> User-Agent: quilt/0.69 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sechang Lim [ Upstream commit a48802fb2cd2d1e23651989f8ff4d15e9d5dad54 ] start and len are u32, so u64 last = start + len; evaluates start + len in 32-bit and wraps before storing it in last. The bounds check if (start >= offset + l || last > msg->sg.size) return -EINVAL; can then be passed with an out-of-range start/len, after which the pop loop runs off the end of the scatterlist and sk_msg_shift_left() calls put_page() on the empty msg->sg.end slot: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] RIP: 0010:sk_msg_shift_left net/core/filter.c:2957 [inline] RIP: 0010:____bpf_msg_pop_data net/core/filter.c:3103 [inline] RIP: 0010:bpf_msg_pop_data+0x753/0x1a10 net/core/filter.c:2984 Call Trace: bpf_prog_4cc92c278f4d5d56+0x1b1/0x1e8 bpf_prog_run_pin_on_cpu+0x107/0x320 include/linux/filter.h:746 sk_psock_msg_verdict+0x357/0x7f0 net/core/skmsg.c:934 tcp_bpf_send_verdict net/ipv4/tcp_bpf.c:420 [inline] tcp_bpf_sendmsg+0x766/0x1ae0 net/ipv4/tcp_bpf.c:583 __sock_sendmsg+0x153/0x1c0 net/socket.c:802 __sys_sendto+0x326/0x430 net/socket.c:2265 __x64_sys_sendto+0xe3/0x100 net/socket.c:2268 do_syscall_64+0x14c/0x480 entry_SYSCALL_64_after_hwframe+0x77/0x7f Widen the addition with a (u64) cast so the bound is evaluated in 64-bit and a len near U32_MAX no longer wraps below msg->sg.size. While here, change pop from int to u32. It counts bytes against the unsigned scatterlist lengths and can never be negative, so the signed type only invites sign-confusion in the pop loop. Fixes: 7246d8ed4dcc ("bpf: helper to pop data from messages") Reviewed-by: Jiayuan Chen Reviewed-by: Emil Tsalapatis Reviewed-by: Kuniyuki Iwashima Signed-off-by: Sechang Lim Signed-off-by: Jiayuan Chen Link: https://lore.kernel.org/r/20260615021959.140010-6-jiayuan.chen@linux.dev Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- net/core/filter.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/filter.c b/net/core/filter.c index 8eca5b0978c988..80aa924d3e649d 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -3007,8 +3007,8 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start, u32, len, u64, flags) { u32 i = 0, l = 0, space, offset = 0; - u64 last = start + len; - int pop; + u64 last = (u64)start + len; + u32 pop; if (unlikely(flags)) return -EINVAL; -- 2.53.0