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 7D5D23750D6; Wed, 10 Jun 2026 19:53:18 +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=1781121199; cv=none; b=c60u27VuOb0WoFK49KAaSmQALyvDkc+6YaPfqtu9Cwl3MljCQbmZXciABEM6siECZgmuhFbMEeMGsRF1Ulmq9UkZS4SFeIVDaWlW9kF9GyZ1BhugU74LF5dd0Ac06hGmzerrJDdRIRNfoufoOFbdPRYBk5U0f+yReAjQf3uff5A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781121199; c=relaxed/simple; bh=VuUv56tfc8o3tvHTP3XsvseeHvFF87RmN7cfjS6xjiw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SOD1YOXA7BuztPYM81q1jGagBqR61sqHDrqUQMIrJA/ADs8DMpGv+e0a2rR9f1BPeMfLS6u2Ac7MUm1sBCuXaYSQNPHoCUVj05ap1zym8YOAsq9kYpbrTLDihPKrEoJDnI/Edm1jayiQ36awvv+Ffe2wznGjZ/nSDE1ZGmkmbFk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=V6Z2Iimj; 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="V6Z2Iimj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78BC11F00899; Wed, 10 Jun 2026 19:53:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781121198; bh=TPI4lcTF/Ad7mcGqGqraHw+fFAKGwPr0XI1FGHfajLY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=V6Z2IimjOvw3vBdHBiJ7T+HQZVQHDHa97arSOmR3d4lMhbn2xINEV60QhmGoQYgns /gS7jBjFDg0G43SDY1MgcGE9qL3UaQzFAQF7VbxZFuuWiimWJSGvFFAj4LjCYzyW9I Aqf/YDYp/OZN1119fk2CHVczpp+FWALV2LRuPvHP5N2/V6x9zw+2V0BRCepIOW8UA5 7LKyHd9DlmECPHYsMwSh2AbYXzP+fnee+5z8DlSDDzL265N3lzR5gsjaW4PQGSB/Ex qFaBFGQNJkq37Ll+tDn9Z7ffZWTxtgooTkOMvS62A/sMYNsixCqqb6DadOWqsnAFap Vwg4emlpH3MXQ== 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 , "Claude Opus 4.6" Subject: [PATCH 14/23] perf hwmon: Guard label read against empty or failed reads Date: Wed, 10 Jun 2026 16:51:47 -0300 Message-ID: <20260610195157.2091137-15-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260610195157.2091137-1-acme@kernel.org> References: <20260610195157.2091137-1-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-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo hwmon_pmu__read_events() reads label files with read() into a stack buffer, strips trailing newlines, then checks buf[0] == '\0'. When read() returns 0 (empty file) or -1 (error), the buffer is never written, so buf[0] reads uninitialized stack memory. If the garbage byte is non-zero, the code falls through to strdup(buf) which copies arbitrary stack data as the label string. Fix by checking read_len <= 0 before accessing buf contents, closing the fd and skipping the entry. Reported-by: sashiko-bot Fixes: 53cc0b351ec99278 ("perf hwmon_pmu: Add a tool PMU exposing events from hwmon in sysfs") Cc: Ian Rogers Assisted-by: Claude Opus 4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/hwmon_pmu.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/hwmon_pmu.c b/tools/perf/util/hwmon_pmu.c index bdcbe887579a1f08..efd3067a2e591050 100644 --- a/tools/perf/util/hwmon_pmu.c +++ b/tools/perf/util/hwmon_pmu.c @@ -295,8 +295,11 @@ static int hwmon_pmu__read_events(struct hwmon_pmu *pmu) while (read_len > 0 && buf[read_len - 1] == '\n') read_len--; - if (read_len > 0) - buf[read_len] = '\0'; + if (read_len <= 0) { + close(fd); + continue; + } + buf[read_len] = '\0'; if (buf[0] == '\0') { pr_debug("hwmon_pmu: empty label file %s %s\n", -- 2.54.0