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 AD04C43C7D6; Tue, 21 Jul 2026 22:11:12 +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=1784671873; cv=none; b=JHZVclwIACIPluM3e96g7ELGwPGAgezqq52NYw6wT+u6fvHvnU+FqkSXR+fZccSbFvSapuGyVdhKIaAk7p994V43d1cSrzPpji+/Md6UyWRe3ghOKatMBcLEAtRwZnLoVrNDAf4yuR0N8ueYuJFavAM1tiN1oU+Pe5TJaKMwDjM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671873; c=relaxed/simple; bh=pTx/IVBUuJ1b49/ene75QxHHIF0abfJakJxOEH5I09o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=d1qtTndFjEXmbFVMNWSaZAO214+wQvC7XEqhpFRFotCICs2QvU0/iBKOw8ID+/YXINkjzlKk5nhwIHigWUmjm3cBMYH9lrIMFqpuE5R2Pmz1+CRaf6YgWVFYSfkZn/oVk8XICPeDpMqdJrNuulFUxVizypSX+RPx4AEFK9LERLk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xEX/w9k7; 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="xEX/w9k7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EFE51F000E9; Tue, 21 Jul 2026 22:11:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784671872; bh=q+9mxK2k7eNUxIe+MgJDD5btDbM/ydyDIQXK4hH3DyQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xEX/w9k7uiZyapbtDJyRKnw1zaIro87vO1IZ5JILkQtaV1MjmV44FoD9Z9Z6BFaSB cKDl61WFGNa6xOKxQZXnyRRmxVi4GvTzMGL4u508Qn/4DIlCDnsMr750S8y8h2vR8n CpwJpDdE5NKGnLsAaQS58kdh/5EdUZaWpV/PAbnI= 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 5.15 412/843] perf pmu: Fix pmu_id() heap underwrite on empty identifier file Date: Tue, 21 Jul 2026 17:20:47 +0200 Message-ID: <20260721152415.305565779@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@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 5.15-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 eafd80be66076c..ce577e5393f92f 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