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 537951C761F; Mon, 14 Oct 2024 14:58:43 +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=1728917923; cv=none; b=mRWFKEkD04a/gV9rybs0NeRsQmtkW0Tg2DuVxqmRCZ82Bn8O7Bw/0JE0S8HlltdovFa8yn23rQ6dgsz9ZnTbNdzv/ci/bp/7pCtyCRsawckKIiGKOIdOAE/9i5AnH7rJ/KcenD6OQSfgfZ+Yxew0rD9DlGON57Bpvn5QIVU2QlA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728917923; c=relaxed/simple; bh=U2QqdkpPoHVUY1KgcGp5Jl3P1aXsqKlFmU+5BNIFzME=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=bsIzYb1ECnir5wFFdciw5J0Y8i5f80g9ZbuwhCIsTywrTwCFb/Ias8+3Hab8YJU1Ixsy0CDNk2RGA7f4JMk0m91P6oy7PAcJ+GRE2rAwbXiHXpgJuGNsh+wuQKvdRlpN71lmz280HoR+KK7ONv64HGKTU819MXXsm8EZ1RKMio4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xe3hVBmp; 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="xe3hVBmp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AB139C4CEC3; Mon, 14 Oct 2024 14:58:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728917923; bh=U2QqdkpPoHVUY1KgcGp5Jl3P1aXsqKlFmU+5BNIFzME=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xe3hVBmpVsFZr5/5O5nUIts/sYq7VGsqHji+ZVpjLGpmwK6uJHo/fVdOmTDAsq0QU uI8D4bQZYOIFUQ11ilbaZb0dxLNkssnpgSfCskZzu1LrxG04L88J0qsS0VGuMokSw2 LbQ/oiPeXoPc3LuNi6TrEg+gcudAc+IHTxECk3ws= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Sasha Levin Subject: [PATCH 6.1 174/798] bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit Date: Mon, 14 Oct 2024 16:12:08 +0200 Message-ID: <20241014141224.763000958@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241014141217.941104064@linuxfoundation.org> References: <20241014141217.941104064@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Borkmann [ Upstream commit cfe69c50b05510b24e26ccb427c7cc70beafd6c1 ] The bpf_strtol() and bpf_strtoul() helpers are currently broken on 32bit: The argument type ARG_PTR_TO_LONG is BPF-side "long", not kernel-side "long" and therefore always considered fixed 64bit no matter if 64 or 32bit underlying architecture. This contract breaks in case of the two mentioned helpers since their BPF_CALL definition for the helpers was added with {unsigned,}long *res. Meaning, the transition from BPF-side "long" (BPF program) to kernel-side "long" (BPF helper) breaks here. Both helpers call __bpf_strtoll() with "long long" correctly, but later assigning the result into 32-bit "*(long *)" on 32bit architectures. From a BPF program point of view, this means upper bits will be seen as uninitialised. Therefore, fix both BPF_CALL signatures to {s,u}64 types to fix this situation. Now, changing also uapi/bpf.h helper documentation which generates bpf_helper_defs.h for BPF programs is tricky: Changing signatures there to __{s,u}64 would trigger compiler warnings (incompatible pointer types passing 'long *' to parameter of type '__s64 *' (aka 'long long *')) for existing BPF programs. Leaving the signatures as-is would be fine as from BPF program point of view it is still BPF-side "long" and thus equivalent to __{s,u}64 on 64 or 32bit underlying architectures. Note that bpf_strtol() and bpf_strtoul() are the only helpers with this issue. Fixes: d7a4cb9b6705 ("bpf: Introduce bpf_strtol and bpf_strtoul helpers") Reported-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/481fcec8-c12c-9abb-8ecb-76c71c009959@iogearbox.net Link: https://lore.kernel.org/r/20240913191754.13290-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/helpers.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 758510b46d87b..d12e696fac74f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -509,7 +509,7 @@ static int __bpf_strtoll(const char *buf, size_t buf_len, u64 flags, } BPF_CALL_4(bpf_strtol, const char *, buf, size_t, buf_len, u64, flags, - long *, res) + s64 *, res) { long long _res; int err; @@ -534,7 +534,7 @@ const struct bpf_func_proto bpf_strtol_proto = { }; BPF_CALL_4(bpf_strtoul, const char *, buf, size_t, buf_len, u64, flags, - unsigned long *, res) + u64 *, res) { unsigned long long _res; bool is_negative; -- 2.43.0