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 C26072D8376; Tue, 21 Jul 2026 20:40:32 +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=1784666433; cv=none; b=NOhTSjcPsOgod7oWkJCHxa87gSN+xcTGzOANA5p6KbY2M91LFPwGS1WB15Qii7ISH47DFXbgabk/NC83ERJqMENHh3hcBOdzRuVFxc0fTf4uWV2WbYxn2/SNxDyAwCQ/nelo0CdrFfqWc3HarH6UjeI7ZcPYxWuYamJwklDvj9g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784666433; c=relaxed/simple; bh=pAqWi/cY4++lk1d3dHVH0DqXgxfK79xWL24sOh29fAc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=TlfLVmDPYGcAd05chsjB2TOesNTo5VIVZEG+4lDjYJ+PTJQhdGQYj8YQPHe6eS57t2P+aQidTT1zIne/YIFW0fMAZedexVVnvSoMPIddUhVGtt+Zl92rW5ceZrWGdf7hgQZffkRRV/hh7Gb78nFAih6xiPwGlkRPIukkr4XLYgg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FrzGi8cA; 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="FrzGi8cA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3424A1F000E9; Tue, 21 Jul 2026 20:40:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784666432; bh=T2fr6pMRMKUWL2T8nrovfEDBs8h+M4CCI/dFblbE8qY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FrzGi8cAzHJlFUFCgN8PNNmbNTmNi1MOenIoKLL7eKlIVGCGox7RdF0swtJFr1ij4 O8tYVGWsUqmcJX7dkx8UWeAbUMKFuo5Dynw/7k0jiDRjaRrp7XQEE1C0lmp/va3kW6 cWnRKticI548bilTYU9rrnBp56ooLAj3tKLua+hQ= 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 6.6 0680/1266] perf pmu: Fix pmu_id() heap underwrite on empty identifier file Date: Tue, 21 Jul 2026 17:18:37 +0200 Message-ID: <20260721152457.074650931@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@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 6.6-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 2587c4b463fa88..e05dff925aa069 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -774,6 +774,12 @@ 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