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 A3E2B35C6B0; Tue, 21 Jul 2026 21:29:50 +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=1784669391; cv=none; b=UGWw2AQcNjHylcrcaScXc2bdtlqgmWIbUWIRn5fuq6bn1LM9fDSohEolT5tNnW/ScpNyH2CHsP4mGjzkvQ/GfbUqme1UmcQhSS/8VsQJYwPlJL84UYdY0rnCdLHEsn9exootz16826NMQjEDDN1cuYclzgVoKsleb0V0lJPXgkc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784669391; c=relaxed/simple; bh=TBRufquj9S5Q+mjtB+nwTYW4uW4a5SyMRcGVslkd7EE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=bXoV29RQIqQM0H0FQovP0+aMHpLiszKP1UsAhehKOh5whq/G6r3NUV13fS2eAX906hqFBwlD2g6iZ021HsW/SPKN/iwjtPX+WOCPUYjWTXYpBKBTrw/zSZC/iLNdXCpjuDkik/4kTqR+PRRJyFFu05KB9MIzWi04P7LCFG3Oqds= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=U+NIUPg9; 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="U+NIUPg9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1456E1F000E9; Tue, 21 Jul 2026 21:29:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784669390; bh=PAdmzIZLTsjgMZjfRmKLgZ7p3B87V+ImokJAk1BZvYY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=U+NIUPg9Or40+QFeETKucCpX4BviThVEQBZua01iW8lktl2iflU4n6qyfd7GV3YWY CDv1rE2YvM5pvsWE5j940auyeYb5/Iln73gkab9AUqG9rOahhF6wt4iCqkrypcKVck W8B07VOajqFgSlDp73UJfAKP23oKuijbkfngEDNg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, sashiko-bot , Stephane Eranian , Arnaldo Carvalho de Melo , Sasha Levin Subject: [PATCH 6.1 0537/1067] perf pmu: Fix perf_pmu__parse_scale/unit() OOB access on empty sysfs file Date: Tue, 21 Jul 2026 17:18:58 +0200 Message-ID: <20260721152436.619622069@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 33035f7dd4e49f3f117e70c5e36c8c1ae88d37f2 ] perf_pmu__parse_scale() reads a PMU scale file then accesses scale[sret - 1] to strip a trailing newline. Only sret < 0 is guarded, so an empty file (sret == 0) causes scale[-1] — a stack buffer underflow that reads and potentially writes out of bounds. perf_pmu__parse_unit() has the same pattern: alias->unit[sret - 1] with sret == 0 accesses the byte before the struct member, which may corrupt the adjacent pmu_name pointer field. Change both guards from sret < 0 to sret <= 0 so that empty files are treated as read errors. Fixes: 410136f5dd96b601 ("tools/perf/stat: Add event unit and scale support") Reported-by: sashiko-bot Cc: Stephane Eranian Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/util/pmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c index 6761a208c0d9e9..db1418c9369651 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -162,7 +162,7 @@ static int perf_pmu__parse_scale(struct perf_pmu_alias *alias, char *dir, char * goto error; sret = read(fd, scale, sizeof(scale)-1); - if (sret < 0) + if (sret <= 0) goto error; if (scale[sret - 1] == '\n') @@ -189,7 +189,7 @@ static int perf_pmu__parse_unit(struct perf_pmu_alias *alias, char *dir, char *n return -1; sret = read(fd, alias->unit, UNIT_MAX_LEN); - if (sret < 0) + if (sret <= 0) goto error; close(fd); -- 2.53.0