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 AF90C44D03B; Tue, 16 Jun 2026 15:39:33 +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=1781624374; cv=none; b=ZjGSh9zoVZ+2xjgBvYd01JEnFbREVDNDjVYx5q+sp2cx7DOQTlkg1Xc+F4DjAGgLjmVEW3sPGsam3OPSjNrhvRalIOw2JI+mlYDzAsAjPWdK2cMvTH48k/adgTDH50VDQyTje74ek9ra5OUHYMVEm80I3lzNoXWu4UcaF/e2DQ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781624374; c=relaxed/simple; bh=RVGBcO29wgKJ4yfBeZ2A2bjxMjP2UrpR7h5Kt/VICis=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GU7OMpjUTIuvUOUvT1DBuZ4ailN/srOLv69S9+mLWqTBVlvZE4A4G1wBzIt4FLenaNmyLe8rKupmdM0k+Vmw9iiBTqNhJVnlK5vrkkanADIobwWzfy39p8btnuGcyaTiO3CMV9JWFRr4poLPNzM4JXQatzv3BXCtGPvT/rALrBE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=PdVzFTLN; 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="PdVzFTLN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5245C1F00A3D; Tue, 16 Jun 2026 15:39:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781624373; bh=/s1fLeEhbdKCUY+af/w62lZXukqf8aMeTrgtihW+DmY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=PdVzFTLNgfXDoaRWnTC+YIwy8dwBK/0YNSKdXfkO697GVGwiq4BC/3YHiT1QnkEyY fPFps/cipMpxltIXr0VKzE1c0J9Kqv+xKafnFw6pUlRwE08iXPcZA1RWQwTXn3ihAD gFbFfTPdgl0v+AEj3/euAq4+cdwYFEpbNmhZbcIjRwOk+0pGIK/XKzonur3Ji1gpJ8 vKkGGf/KyssiY8BlNsoqnNF2upNU8sM4AU31v0zKRyWsqk6qfujn7SwnLqZ/1FfjO7 FXQEnamwSM0/j6hGDiN7FKmgszM1OuqE1qbp6l9bnFsZ1seO9jLc5vdfBopyR1Wp3N hxeKb4+ue5KQw== 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: Tue, 16 Jun 2026 12:39:13 -0300 Message-ID: <20260616153920.6852-3-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260616153920.6852-1-acme@kernel.org> References: <20260616153920.6852-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo machines__findnew() and machines__create_guest_kernel_maps() use sprintf() to build paths by prepending symbol_conf.guestmount. Both 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. 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