From patchwork Tue Jun 20 16:30:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13286180 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 DE4C618C10 for ; Tue, 20 Jun 2023 16:30:26 +0000 (UTC) Received: from mail-pj1-x102b.google.com (mail-pj1-x102b.google.com [IPv6:2607:f8b0:4864:20::102b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AC292172C; Tue, 20 Jun 2023 09:30:24 -0700 (PDT) Received: by mail-pj1-x102b.google.com with SMTP id 98e67ed59e1d1-25f0e0bbcaaso1336121a91.3; Tue, 20 Jun 2023 09:30:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687278624; x=1689870624; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=lzAEwWz2g31UMs4g4MUixj1iNbtJ/dM5TZGhqlQXR9c=; b=UQ6WFD4h9OxD0y4f9f3LdKVC6o2VYevQHKIdBZBY9ZsUWR0wlgh+hJFK7TFmZHxh3P 5FmQjvBFlqgfg6B8OQLMLZb0ZJyuAthh38Y/k4FxqZJiBpfL9titLy73qAFOC+a+5dCJ Ulvyxi08lUcpnzw44NJRg1Q4n4CJPgJygHBjhJ0dcgW8CFFJ7oyOzdwmKkueUdfLji7R Q4OeI3PvjxGfi2CbSz8B34J+p5qIT0T5GowFiGJpUrZpqzWdogBxIb+Rc54qixkTpKEw PYCSEESKzutUXkwmc6NcZ/XWPupCooEEX6D/NQymlPDq7BVE+bkHupZ9y5/fGmflM7tc khVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687278624; x=1689870624; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=lzAEwWz2g31UMs4g4MUixj1iNbtJ/dM5TZGhqlQXR9c=; b=dnp5mxahvONCD1BIpQejKgzY58xpyJxtf8qtdpxL5z+/Ie9hVw3k6Ag9bbQzcFr5BH hF6k8EKQaj60UEodFulHe5Zy/WlHZY/UjgWOUautvfvp0GJKpb0B73xFtbIxhJZVk35q l9fYZATrI62oY0/yMmYTjuzeD4WLgADMdggQnyneNv0Jo2DOX/vMH9lRL9Yi6vRztTLN z+7kViw2i1/3r46YPcLF1PX/6l0/skUQcTl57XRoe5EtydwxQ4C9Zz8kiMlkRxeXJ0G2 T3ig9CRC2Xn51ahgi5A3+pi8fH1rvxyHTFus40/VWYSvm15KumRUdM6N+5/vxVgzAbHY ycRg== X-Gm-Message-State: AC+VfDyxnROwYVqXia6R2DoWbcfozGV88seEPtSW/y2CuX6zofSpT2Hc 1TTX+ZBwho7lvzjs4NCHUPI= X-Google-Smtp-Source: ACHHUZ7C0y/gigQKKulCdgk5D0IrXKAkn7+AtANMzbaiQVx00e4ZZnlvu4oc7X76Z0zcZ6Z9o86XhQ== X-Received: by 2002:a17:90b:30c9:b0:25b:bff5:5310 with SMTP id hi9-20020a17090b30c900b0025bbff55310mr7291590pjb.14.1687278623951; Tue, 20 Jun 2023 09:30:23 -0700 (PDT) Received: from vultr.guest ([2001:19f0:ac02:b96:5400:4ff:fe7b:3b23]) by smtp.gmail.com with ESMTPSA id t8-20020a17090a3b4800b0025c1cfdb93esm1854286pjf.13.2023.06.20.09.30.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 Jun 2023 09:30:23 -0700 (PDT) From: Yafang Shao To: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com, andrii@kernel.org, martin.lau@linux.dev, song@kernel.org, yhs@fb.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, quentin@isovalent.com, rostedt@goodmis.org, mhiramat@kernel.org Cc: bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Yafang Shao Subject: [PATCH v4 bpf-next 04/11] bpf: Protect probed address based on kptr_restrict setting Date: Tue, 20 Jun 2023 16:30:01 +0000 Message-Id: <20230620163008.3718-5-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230620163008.3718-1-laoar.shao@gmail.com> References: <20230620163008.3718-1-laoar.shao@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net The probed address can be accessed by userspace through querying the task file descriptor (fd). However, it is crucial to adhere to the kptr_restrict setting and refrain from exposing the address if it is not permitted. Signed-off-by: Yafang Shao --- kernel/trace/trace_kprobe.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 59cda19..e4554db 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1551,7 +1551,10 @@ int bpf_get_kprobe_info(const struct perf_event *event, u32 *fd_type, } else { *symbol = NULL; *probe_offset = 0; - *probe_addr = (unsigned long)tk->rp.kp.addr; + if (kallsyms_show_value(current_cred())) + *probe_addr = (unsigned long)tk->rp.kp.addr; + else + *probe_addr = 0; } return 0; }