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 EA8DC1D89F5; Tue, 15 Oct 2024 11:47:41 +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=1728992862; cv=none; b=io1j8o1bQmF5Snc/c7/5sMATS1B1j2qGK1+L3ALGsPoCUXbmkZTt7mXQ1BlWatq4tL8P+7u9/PlspgAHYLRRQOwfKWJcyBXz17nLnHQLNBRFghkPIB2lBF46tKK9bRZQVDdQiKLbzxv3xPR5GyBJPb/cnnRsaOV6UHnYqZa2q0A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728992862; c=relaxed/simple; bh=mh/EzTFHeOViYH2/PS7t1YpV8CFZArZD4ZyrGTOvjcg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PMTK8CUDp0N6tk7O1UWU8vEbtswF0Z92j5/tUm+zz0qMQ1MjvrGbzMIgv69HsrHFGwLz+JHLioLTlKGbKbHtLyiHMhZdQ8ObERYtog7X5D++HMltboQGG9TEWwp5N2YjxvEpT3GTu7/U0zNtmOlLlnmU/6UKZG/HdbzXbEYBQZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1Zpz/1bp; 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="1Zpz/1bp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17515C4CEC6; Tue, 15 Oct 2024 11:47:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1728992861; bh=mh/EzTFHeOViYH2/PS7t1YpV8CFZArZD4ZyrGTOvjcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1Zpz/1bpCk5z7gRznKMvdKLQljGYYx95EZYrlkCEZt2IVQ9+rJeVukTgcMGgI5VRb X2sgvje0kvo/N44oAdgCuMfy1/B025mf25Osc7Y1bmAjmTX03tMqUc18VTegcA2RtE gaf7aLICOY2nHLlVR6smCbJ0tt92OnYm/zHV5Kv8= 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 5.15 213/691] bpf: Fix bpf_strtol and bpf_strtoul helpers for 32bit Date: Tue, 15 Oct 2024 13:22:41 +0200 Message-ID: <20241015112448.812711432@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241015112440.309539031@linuxfoundation.org> References: <20241015112440.309539031@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 5.15-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 273f2f0deb239..13f870e47ab6d 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -512,7 +512,7 @@ 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; @@ -537,7 +537,7 @@ 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