From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 95AC3358367; Mon, 15 Jun 2026 21:37:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781559433; cv=none; b=JGBsBXvL178s8ETVaM6mzlN+jlVXg3gMvFCncC6D5/e6fmyAePlE+mc/8swu4gHc5HilppbaF/QFgDCHObpFtMQ7sKhrVfW7BLrNONHlLC1G8Qqt1h+9ABXYXXl1ZGK02iP9GjHM8MTigeHNeWfRCmn3AmAdl/vk/XKD5CmkPUA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781559433; c=relaxed/simple; bh=2gKseSF4cqPlZO4s6Gg3jNAhU2lz/g6pc58kaKDO0tM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=mixdZ6vA/UHx6o+ZHqzzHijYD7JT6y6rzhLLdWInrvtmyXeuKCHma2U8JvDmvwo69N/o79Ci1PiTf9ZRCTmlspkAoKJ9Cs04VeMufpvp3m0dV6egnU15mOIf1lgsO9Pz6R74nWPZYOPfu9q81KPB8gJV6HkjSj/3WgJ0iJVfCpw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f791FrhJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="f791FrhJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E126B1F000E9; Mon, 15 Jun 2026 21:37:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781559432; bh=7duyD0OYxB69I7KGQOFcyyHodAqqfDzYOr3MNZQgVpU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=f791FrhJjpz3RMBihY3QWmirHcsLOHg54TU11A1WLpj64QGNLPVXYsGmFDsJ3UBD+ JHx2rC4udRRsjQ+MRkiHvBx5vTiVnlnjW9sI2NC7EOXe9Yljzp7XEiwC+LU1kuRmZX Bv9crr1JI6KpV05KrF52PIBzpBmBK86kJfKMspd5eNT7rTYras4FdCNS2AzqK+Iwv5 Pse70pL56IFy7GE6ftVNdq5jdUXUORIuLcNwgqEMD/PR6Q3edRWbyP1yv+XqHizkBJ +7kDqhmEn/jeJ2nVUHOefVGF+Q+uwaK73RzarJIvKarPADRYc8CQYV6tayN+IRkiTO MoJFKmumn8f0Q== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot , "Zhang, Yanmin" , Claude Subject: [PATCH 2/9] perf machine: Use snprintf() for guestmount path construction Date: Mon, 15 Jun 2026 18:36:50 -0300 Message-ID: <20260615213657.35776-3-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260615213657.35776-1-acme@kernel.org> References: <20260615213657.35776-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo machines__findnew(), machines__create_guest_kernel_maps(), and get_kernel_version() use sprintf() to build paths by prepending symbol_conf.guestmount or root_dir. All write into PATH_MAX stack buffers, but guestmount comes from user configuration and is not length-checked. A guestmount path at or near PATH_MAX causes a stack buffer overflow — and a truncated root_dir propagated to get_kernel_version() would overflow its own version[PATH_MAX] buffer when "/proc/version" is appended. Switch to snprintf() with sizeof() to prevent overflow. The subsequent access()/fopen() calls will fail on a truncated path. Fixes: a1645ce12adb6c9c ("perf: 'perf kvm' tool for monitoring guest performance from host") Reported-by: sashiko-bot Cc: Zhang, Yanmin Assisted-by: Claude Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/machine.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 7cf20ace3dbb5e55..fb960fda55f4f2ee 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -334,7 +334,7 @@ struct machine *machines__findnew(struct machines *machines, pid_t pid) if ((pid != HOST_KERNEL_ID) && (pid != DEFAULT_GUEST_KERNEL_ID) && (symbol_conf.guestmount)) { - sprintf(path, "%s/%d", symbol_conf.guestmount, pid); + snprintf(path, sizeof(path), "%s/%d", symbol_conf.guestmount, pid); if (access(path, R_OK)) { static struct strlist *seen; @@ -1261,9 +1261,9 @@ int machines__create_guest_kernel_maps(struct machines *machines) namelist[i]->d_name); continue; } - sprintf(path, "%s/%s/proc/kallsyms", - symbol_conf.guestmount, - namelist[i]->d_name); + snprintf(path, sizeof(path), "%s/%s/proc/kallsyms", + symbol_conf.guestmount, + namelist[i]->d_name); ret = access(path, R_OK); if (ret) { pr_debug("Can't access file %s\n", path); -- 2.54.0