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 D8FFF30EF9A; Tue, 21 Jul 2026 19:37:00 +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=1784662622; cv=none; b=OtPVW/mL6i52/tgE5crIo+4S3owokWA0eZqlCONam4aDeIZjmv4GCB5mJpY4dYmP/o42wkF/TU1NxT30hX63I+4URE+MEYauYkG3p0CLFyf+0BrBFN9QCrtyop4BCxdkLAe+hBg2hfzO3BU4/JmH1sXB+uHf7bn7H+rVvHRb5Ag= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784662622; c=relaxed/simple; bh=uyNd908MMC4dL227AIcPSuQudYlPw3jxxVym/CX4wVg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=AthqDAIf2MrxJ5w6N4cI8+p9RLiG4L9bQPgrqxPy94opepyxOvv2H2Fa/HX+2BbE9HJXwQZos3k11QPyJB1ySLhl5MJl31cVXvW555X9frvOKLICxXRff/XT6LBTNGnI2Mx/du49kGIyaVxdk8+yYTOMyCQH1KElbr6YRpD3mIE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=i4ktRpOe; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="i4ktRpOe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49CFA1F000E9; Tue, 21 Jul 2026 19:37:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784662620; bh=F2pgButWyTAy6nH1+mv9MqZDYSRoZnI1IKhAZXVNGlM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=i4ktRpOeLzHUaKfI+H8vOcB0JWExBgnKrOp/1Yzg3fPRnQXgPFKEYU/I18W6kW38P sFfUJpPQDnDQGIbyxWtLY1mEeafdgB75wbXSnBuT1ar9LhmLeLyvA/IBlD6rojvUK5 reCWsKSBVmzvY2L+h0yO2JxhHcDYxUy/AvLKcd08= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, sashiko-bot , John Garry , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.12 0515/1276] perf pmu: Fix pmu_id() heap underwrite on empty identifier file Date: Tue, 21 Jul 2026 17:15:58 +0200 Message-ID: <20260721152457.636957506@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152446.065700225@linuxfoundation.org> References: <20260721152446.065700225@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnaldo Carvalho de Melo [ Upstream commit 836455e6dbd34eb3d12eeab5e2d2b9a7f1512459 ] pmu_id() calls filename__read_str() then strips the trailing newline via str[len - 1] = 0. If the PMU identifier file is empty, filename__read_str() succeeds with len = 0. len - 1 underflows size_t to SIZE_MAX, writing a null byte before the heap allocation. Add a len == 0 check before the newline stripping. Fixes: 51d548471510843e ("perf pmu: Add pmu_id()") Reported-by: sashiko-bot Cc: John Garry Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/pmu.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 8885998c195308..bf9793a995316b 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -796,6 +796,12 @@ static char *pmu_id(const char *name) if (filename__read_str(path, &str, &len) < 0) return NULL; + /* empty identifier file — nothing useful */ + if (len == 0) { + free(str); + return NULL; + } + str[len - 1] = 0; /* remove line feed */ return str; -- 2.53.0