From patchwork Fri Jun 23 14:15:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yafang Shao X-Patchwork-Id: 13290674 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 0B02BAD42 for ; Fri, 23 Jun 2023 14:16:25 +0000 (UTC) Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A41622133; Fri, 23 Jun 2023 07:16:22 -0700 (PDT) Received: by mail-pf1-x42d.google.com with SMTP id d2e1a72fcca58-6685421cdb3so1314679b3a.1; Fri, 23 Jun 2023 07:16:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687529782; x=1690121782; 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=Du4qFBhVRDavQkjSfw1UhiKH87F0Og4EJXGDRJA8147dzuQf81Hrb1r0iSbe3Zcqob DUpB5PGz+8H5VIelumpfCsw1s+76Kh1xcvuJLz7HdhKGOuvBkm3Tb5XFwUPjaY3TsYOz cNDD0ugNByKP6tU1VyGXddf2TShai1657KLml4Qwk1nHJQWgVG438k4bypP7NmZKSEP+ u9hXgIGa0dvpKtXZYC2z62p7YIExGRi56bU2aHwulqlQnsmkoCs6GYgwTqF1IDGjrI0e wBEap7C6AX/XGu/EbUoMgbzKy1eqMe4oRt50FVtT5y081LQGHdWJSKYmjLigvjyh6JSw qdMQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687529782; x=1690121782; 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=doqAwBR1olxlHi//nHooGKZkLXF5lWYKRurM8KC2/2KinlVfdJQ01eyWAEYh+deWm/ CD9c7QnWn55xxmP1YdVbnmaftm00Bcas32UNfLlyICRgIAWRDKMvdkTy/f778hCAvi2m r2xPXvTfqbRcCMkWBpX4x6DCV43pHfvY2JXfSasQSjDBlyS+20U9p7fbPujkDZ5U2KkM T8s+8n9K9BgP42+0V2eFN2/suommcarh+usUkZOaubnWWB9yMLggyGXfAW5WA9FhQtTI j2o/D58MG1UkPn26fxYug1/Ms0rtmFKHQLTnJtKChWaalL7RLkDz/YThehEW1TXHCBhN TLgA== X-Gm-Message-State: AC+VfDzRGMnYMaK9NrTEug6Z2qgTktQLMzOn57b7womhQu91l64Pa+3W 94JyHAU4SYiwofGtDGUbWSs= X-Google-Smtp-Source: ACHHUZ55e8bjY7iXV2b6JkCIfWVjUPItrlMUjZIkfG+VE9WwjS2G3DTM5c5W7wEON9WwLU9b05P1cQ== X-Received: by 2002:a17:902:f68c:b0:1b6:c193:96e0 with SMTP id l12-20020a170902f68c00b001b6c19396e0mr3702156plg.1.1687529782117; Fri, 23 Jun 2023 07:16:22 -0700 (PDT) Received: from vultr.guest ([2001:19f0:ac01:1058:5400:4ff:fe7c:972]) by smtp.gmail.com with ESMTPSA id p14-20020a63e64e000000b005533c53f550sm6505942pgj.45.2023.06.23.07.16.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 23 Jun 2023 07:16:21 -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 v5 bpf-next 04/11] bpf: Protect probed address based on kptr_restrict setting Date: Fri, 23 Jun 2023 14:15:39 +0000 Message-Id: <20230623141546.3751-5-laoar.shao@gmail.com> X-Mailer: git-send-email 2.39.3 In-Reply-To: <20230623141546.3751-1-laoar.shao@gmail.com> References: <20230623141546.3751-1-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; }