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 E4B172F4A; Tue, 23 Jan 2024 00:44:25 +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=1705970666; cv=none; b=qMsIGZbukdVhDb84Nz9j8eHufT7JpysZp5H4gfVH+D6w/CesptJ6sIm+WpN+yMPAV+Vf7TWbDOt32mjGMH95Wj0U/JuWrAlGP6smztaj2o12Uy/xZpHp9y66R71FdUH3D1XzN0ZB8vBj7LCIx9bsRId6UPivQnt/pcJEQEqjT1g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705970666; c=relaxed/simple; bh=dFhj9PvsMSaWlbi+3pIMSC34T4ej3fsSyOPMoOUEDFo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MhCdtQqfG5rdeWCsf4PhqhRxCzbjgty5NbeGzKUXjOmTu5ywH/sZaMKPlXO4rSAJlUl1uRzR+hhusNLZiNL3y0dTf9nJVAb54N8fIyPiO2Tn3xDgknZRvONjr81f3xF2ueaiqEV6svM32T1nvmJvzxM9i/dgaZDiJ3a0cWqIb2A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IBEdNZw8; 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="IBEdNZw8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6EA4C433C7; Tue, 23 Jan 2024 00:44:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705970665; bh=dFhj9PvsMSaWlbi+3pIMSC34T4ej3fsSyOPMoOUEDFo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IBEdNZw8rX8QdhUAbW6YBFfWvF0CDmThK96jbepFoas+ItW/aSSoxvvRaGgz2beaQ WxSv8S9iYYfQtV+Hj8mAlvoPca5NSSTgzl+Qaxs+QbJ91s+M91OqCCy4B7iluDaRXd Erqvr6/FRd04LyNr75vsFIfD6W1/tD03TRejRJBw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eduard Zingerman , Shung-Hsi Yu , Andrii Nakryiko , Alexei Starovoitov , Sasha Levin Subject: [PATCH 6.1 083/417] bpf: enforce precision of R0 on callback return Date: Mon, 22 Jan 2024 15:54:11 -0800 Message-ID: <20240122235754.579408564@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235751.480367507@linuxfoundation.org> References: <20240122235751.480367507@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org 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: Andrii Nakryiko [ Upstream commit 0acd03a5bd188b0c501d285d938439618bd855c4 ] Given verifier checks actual value, r0 has to be precise, so we need to propagate precision properly. r0 also has to be marked as read, otherwise subsequent state comparisons will ignore such register as unimportant and precision won't really help here. Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper") Acked-by: Eduard Zingerman Acked-by: Shung-Hsi Yu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20231202175705.885270-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin --- kernel/bpf/verifier.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 142e10d49fd8..024a2393613f 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -7284,6 +7284,13 @@ static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx) verbose(env, "R0 not a scalar value\n"); return -EACCES; } + + /* we are going to rely on register's precise value */ + err = mark_reg_read(env, r0, r0->parent, REG_LIVE_READ64); + err = err ?: mark_chain_precision(env, BPF_REG_0); + if (err) + return err; + if (!tnum_in(range, r0->var_off)) { verbose_invalid_scalar(env, r0, &range, "callback return", "R0"); return -EINVAL; -- 2.43.0