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 05DF344AB60; Tue, 21 Jul 2026 21:29:48 +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=1784669389; cv=none; b=szOG3gxAb9/KqCgkyz3WvYq1/P5sFRPOK/BIMAB06uWqsK77fW/z6oADUDIAomE+w6/e+Tsn4dN4SanZKHnTB1mhwfc2/BPUpfyW4xbIl8UPGRtY9F4Qnww8tt+0SJCyb1ijX2V9iU1t2TLtqQTqzP3P/hYBkRWb4Rt8rItiu6E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784669389; c=relaxed/simple; bh=YOCBts/k3pgxB5yCp639RRYfiGWn6QdaW5Mt3j4komU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=UJ3juH4DN396icD6fiXGsFkYBZyUTyuD1Lf4oqoM5i0/KTlAVnnl9knfjF5PhtOAI+Snuu+u/71lRCiOd4Gun+c6ucOzryfNCLI3SRebfK/OcQSZcmuaik8lmlLgBr8OkCiRKtzW2dIYbhktW+4U/PSOgtJOi0hHCCPyJsMYEMc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=kR6LcJ+J; 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="kR6LcJ+J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6BDA61F000E9; Tue, 21 Jul 2026 21:29:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784669387; bh=wXdL4PtCNcasJsnQSRSjAa+zcWAB3zpC9Y5+Andllxw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=kR6LcJ+JnPyth1lMMPTwQjqv1cZpfV+9QL9yuaIYXtf1wdHkcDfMcVV60fK8KbqQV w9kdhpBgRnsLPhKCo7+L14BwIeSufv5unqmD5W/M0lkCtmIviElQKPXlTPt3LHLkwV tG2q7r2U7dKJN7O+5nbExA1wmO4VDG5gk42xbx9Y= 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 6.1 0536/1067] perf pmu: Fix pmu_id() heap underwrite on empty identifier file Date: Tue, 21 Jul 2026 17:18:57 +0200 Message-ID: <20260721152436.596976702@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@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 6.1-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 9a762c0cc53ce6..6761a208c0d9e9 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -666,6 +666,12 @@ static char *pmu_id(const char *name) if (sysfs__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