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 2E35731F98C; Tue, 16 Jun 2026 01:08:48 +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=1781572130; cv=none; b=KNY4mIYV5uwFwVlPbUtj9RWhFqnX0C42V2HReQGQMFm6yUNTO9sSCFL31809EGgWN+0gSFiWKFtVLwU86++QK+AlX4Fnm3/wXk5Pif6REbf537FCy66OxaSoqKf7l7x02/wk32PftIq7YWB2jbcJCtq4c+PWhm3z3X2DwcK8Pwc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781572130; c=relaxed/simple; bh=D+951BMiZerWJJkB10MWC9Wo471exaC4XfeTCGrDx+c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=K8NArJXAqAytn6/jsx3aqqiZA3xPmgIdMSMPVo2S+zUKEEtetc0vZOVmUA+yZsl0FAnaY9Nf5LMwjNQQOjkD1h0hJGwFGXUkAHGUtmdPKUkSSiwOKuN12A/DmSLrlDXjhGChA0Zhp4xgpnEWtmz6y0Xau71JME8rGQbCBFoCOvg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cU6y3hc+; 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="cU6y3hc+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B4CA1F000E9; Tue, 16 Jun 2026 01:08:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781572128; bh=AXqFVgFdeOvbBMGAhAKr3rkSEfSBR1qgR6jCIPrYcRE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cU6y3hc+LUx0+OOcm5jLmwq8+AFyj+NXF1rLnUBzC9as2hgqXCiDp+c8thuPhX7Zf LkbNDmR/fXYJQA5WVlWbYQL7FXFFLL19dBAKCmGeeoY0QP9dOqcRFK9EOQJ9ofN8My npImrRhPNv9coxbCU3Y0xrPkh41zP9kXaUUPuCZKN4veZSyvT+lhna2P2HU+NOZzZl S8tGhZzVdJO37JtUQ2KSaQUIvEcJBZqOkI58LLCIeG+RTaqjORy1hkddAuJ3CrKCDn Q3p+O0WaGNZ1tfibHkdUhIsjM6mYvZg37KtG90cujmrXw5uAgk1gz+jtQm5KwC/d5p 4LwEYenxSwwFA== 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 22:08:27 -0300 Message-ID: <20260616010834.37618-3-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616010834.37618-1-acme@kernel.org> References: <20260616010834.37618-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@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 9329d319bd033699..0d2ebf6a84bcf880 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -333,7 +333,7 @@ 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; @@ -1260,9 +1260,9 @@ 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