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 C601815E5BF for ; Fri, 2 Feb 2024 19:05:34 +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=1706900734; cv=none; b=cR2lPOb9t77dTV1HFsbeW9w1Burw/H+B6HeMd+0nnqbr6z9DmG1XRCjJeof+07jnjx2AS4g49m0rtHEYR34mXSwwnpGuQjnHxDgY9nHbPB+Op840Bpdx7OHPp0bxG1uNuimyAfJ7I3SpXS6ZeEKKNXF3tIIhZ7CJVOLlvv9L/1I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706900734; c=relaxed/simple; bh=4y0Qcn/ILNJg522cNaeEAJjqBBpestSUNtdyvZ2kPEc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Sh4Wz4QCFcl6BXYm/lAdNWsLgi0na37jf1cx/N/UEiXrmCGs/uIIQaPBQ90LmU3jBiCq6EUsEwobTn2SLN0OrmcGbR0iN6xvJwKK4nfJwBGuXvTExMRHxbi8U2iwFfINiNcKiPFfragC4SitMWqExUaMUYUWU1y6tXYall+tgw8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nmOs5All; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nmOs5All" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33FB9C433C7; Fri, 2 Feb 2024 19:05:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1706900734; bh=4y0Qcn/ILNJg522cNaeEAJjqBBpestSUNtdyvZ2kPEc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nmOs5AllfAeUICasmRjbfMPObvbLP00KnjU9BpWA3R1xhs92whXld4xgthhq1NHfB efqklg9b2D0e8n9YWS+uObEgavOCaInjfd5Me3/5Yect2e7rCB+OhTaLucPkOefh9B GQQX6g51QRRsktsgJjW1pJYMSLpczEDkMinKvSdkDqk3hOTP8ZiHLQF3c/3D1fP64m 3EyjwYWdpUcIfyBww6tDohcricG1b1XCJzeYl+3+C3rp0yznY9D2yXcN19WS4f2l/o b3CpdykDXGi/o3935HxUoKCfkO9MetIBgOo7YRG4IA0oF8S65eSA3RS25dvHdjBN2y QZMorz8Cen+UA== From: Andrii Nakryiko To: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net, martin.lau@kernel.org Cc: andrii@kernel.org, kernel-team@meta.com Subject: [PATCH bpf-next 1/3] bpf: handle trusted PTR_TO_BTF_ID_OR_NULL in argument check logic Date: Fri, 2 Feb 2024 11:05:27 -0800 Message-Id: <20240202190529.2374377-2-andrii@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240202190529.2374377-1-andrii@kernel.org> References: <20240202190529.2374377-1-andrii@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add PTR_TRUSTED | PTR_MAYBE_NULL modifiers for PTR_TO_BTF_ID to check_reg_type() to support passing trusted nullable PTR_TO_BTF_ID registers into global functions accepting `__arg_trusted __arg_nullable` arguments. This hasn't been caught earlier because tests were either passing known non-NULL PTR_TO_BTF_ID registers or known NULL (SCALAR) registers. When utilizing this functionality in complicated real-world BPF application that passes around PTR_TO_BTF_ID_OR_NULL, it became apparent that verifier rejects valid case because check_reg_type() doesn't handle this case explicitly. Existing check_reg_type() logic is already anticipating this combination, so we just need to explicitly list this combo in the switch statement. Fixes: e2b3c4ff5d18 ("bpf: add __arg_trusted global func arg tag") Signed-off-by: Andrii Nakryiko --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index cd4d780e5400..c6f566d9dc3a 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -8234,6 +8234,7 @@ static int check_reg_type(struct bpf_verifier_env *env, u32 regno, switch ((int)reg->type) { case PTR_TO_BTF_ID: case PTR_TO_BTF_ID | PTR_TRUSTED: + case PTR_TO_BTF_ID | PTR_TRUSTED | PTR_MAYBE_NULL: case PTR_TO_BTF_ID | MEM_RCU: case PTR_TO_BTF_ID | PTR_MAYBE_NULL: case PTR_TO_BTF_ID | PTR_MAYBE_NULL | MEM_RCU: -- 2.34.1