From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, T_DKIMWL_WL_HIGH,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE06CC04AAD for ; Tue, 7 May 2019 13:55:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 80D7B20989 for ; Tue, 7 May 2019 13:55:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557237351; bh=4YXwuQ8n+Mqq/6UmCl8odTutlhbgLjaGJtxDalHRu+c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2kzFKZGxFhX4o3RFV/YS1s0huLw+b+86RjA851CkVxYdSqM4ZVRpe4CnLDx0KcvQs Dw3CddH3PwaEwGLLiHDUCv3qivnutchPlVD4DXeo8Yl5RSaP7XmJVBUx7AMBp7WH2x HHguQ9DaA8HqkfiBpZh22Wz73Y2okeJQZZ7IGSdM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726903AbfEGNzt (ORCPT ); Tue, 7 May 2019 09:55:49 -0400 Received: from mail.kernel.org ([198.145.29.99]:57124 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726295AbfEGNzr (ORCPT ); Tue, 7 May 2019 09:55:47 -0400 Received: from localhost.localdomain (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 86A7B20825; Tue, 7 May 2019 13:55:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1557237346; bh=4YXwuQ8n+Mqq/6UmCl8odTutlhbgLjaGJtxDalHRu+c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pnafkpE4qlw7jKn8s8/zR35xVN0A8YHgDu53f0ErqhVo9cl+t0GSODeCMIPeFNUD+ ASTPNHetdXRiS3KHVFxdOso5hIJuCfm85Hqe3d18XHoJ0vJ48Bbfb/0FPAgl79K28z PvfKleyRjtnL77GBp0t4FUNToyEpOP+3jxLvFgtQ= From: Masami Hiramatsu To: Steven Rostedt Cc: Andreas Ziegler , Masami Hiramatsu , Ingo Molnar , linux-kernel@vger.kernel.org Subject: [PATCH v3 1/3] tracing: uprobes: Re-enable $comm support for uprobe events Date: Tue, 7 May 2019 22:55:41 +0900 Message-Id: <155723734162.9149.4042756162201097965.stgit@devnote2> X-Mailer: git-send-email 2.17.1 In-Reply-To: <155723732200.9149.10482668315693777743.stgit@devnote2> References: <155723732200.9149.10482668315693777743.stgit@devnote2> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since commit 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code") dropped the $comm support from uprobe events, this re-enables it. For $comm support, uses strlcpy() instead of strncpy_from_user() to copy current task's comm. Because it is in the kernel space, strncpy_from_user() always fails to copy the comm. This also uses strlen() instead of strnlen_user() to measure the length of the comm. Note that this uses -ECOMM as a token value to fetch the comm string. If the user-space pointer points -ECOMM, it will be translated to task->comm. Fixes: 533059281ee5 ("tracing: probeevent: Introduce new argument fetching code") Signed-off-by: Masami Hiramatsu Reported-by: Andreas Ziegler Acked-by: Andreas Ziegler --- Changes in v3 - Always add +1 to strlen() result. - Use -ECOMM as a token to specify current->comm. --- kernel/trace/trace_probe.h | 1 + kernel/trace/trace_uprobe.c | 13 +++++++++++-- 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index b7737666c1a8..f9a8c632188b 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -124,6 +124,7 @@ struct fetch_insn { /* fetch + deref*N + store + mod + end <= 16, this allows N=12, enough */ #define FETCH_INSN_MAX 16 +#define FETCH_TOKEN_COMM (-ECOMM) /* Fetch type information table */ struct fetch_type { diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index cd8750a72768..eb7e06b54741 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -156,7 +156,10 @@ fetch_store_string(unsigned long addr, void *dest, void *base) if (unlikely(!maxlen)) return -ENOMEM; - ret = strncpy_from_user(dst, src, maxlen); + if (addr == FETCH_TOKEN_COMM) + ret = strlcpy(dst, current->comm, maxlen); + else + ret = strncpy_from_user(dst, src, maxlen); if (ret >= 0) { if (ret == maxlen) dst[ret - 1] = '\0'; @@ -180,7 +183,10 @@ fetch_store_strlen(unsigned long addr) int len; void __user *vaddr = (void __force __user *) addr; - len = strnlen_user(vaddr, MAX_STRING_SIZE); + if (addr == FETCH_TOKEN_COMM) + len = strlen(current->comm) + 1; + else + len = strnlen_user(vaddr, MAX_STRING_SIZE); return (len > MAX_STRING_SIZE) ? 0 : len; } @@ -220,6 +226,9 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, case FETCH_OP_IMM: val = code->immediate; break; + case FETCH_OP_COMM: + val = FETCH_TOKEN_COMM; + break; case FETCH_OP_FOFFS: val = translate_user_vaddr(code->immediate); break;