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 EF4E246EC8E; Tue, 21 Jul 2026 18:08:05 +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=1784657288; cv=none; b=lSLzCyc2ftmFw5l9WQCLwmQDerTia332s2/67vNsg0KMHvJwmATSKcpcRXb3pByBXBsy6vFPTCJdMvgalBlcT4gGu2SJrzMD3jPi+i1dM95XNQmxwztvIkob8mkA+YURQMA6ea77555HJ1hNNbeC+edEWJmT/bBKirBhplbhrig= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784657288; c=relaxed/simple; bh=etHPoKcBEFG4mktnLGlwOT+JOifYxFyl5TtE1WjTABA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=dkDOih0tz4Y0PAXabWTJJTLJZE/YCFmgxU3svnMB/jVRmqDAhVAnO4gqgyKfjWIadmW8ZEZib2AloosDBT0eYjn5ZWJQ3PvU+dgvZnArBR49n+090fGN19jiIR9ODsxzBuYqvKcyBW7cXgz+dsO/x4kAX+VNEPgGEjHfi4F+iFo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Tbp5VZgH; 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="Tbp5VZgH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7A2A1F000E9; Tue, 21 Jul 2026 18:08:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784657285; bh=bflGM35I60UJWtGJ/pBlZa81smeWOFBce3n+A/qo9Iw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Tbp5VZgHjPiCNyBqwpP5YF5FN2feOd0sKOQ5BWFt5v56RjcoXR897MOkkpd8Cn1ro 5eMWrYAqBau0IeL+I5ubNlGnzhJWaJ5HmRbMbPb2sK2EXTiR0Xh9ENUVgl17KtfJHq utCh/sDHb2vuxQgjKPgCn3gbuw27L+0CXeWJP1hQ= 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 6.18 0708/1611] perf pmu: Fix perf_pmu__parse_scale/unit() OOB access on empty sysfs file Date: Tue, 21 Jul 2026 17:13:44 +0200 Message-ID: <20260721152531.304010086@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152514.750365251@linuxfoundation.org> References: <20260721152514.750365251@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 6.18-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 0e65025ef9c2ba..bcdbbaadcbb3ad 100644 --- a/tools/perf/util/pmu.c +++ b/tools/perf/util/pmu.c @@ -328,7 +328,7 @@ static int perf_pmu__parse_scale(struct perf_pmu *pmu, struct perf_pmu_alias *al goto error; sret = read(fd, scale, sizeof(scale)-1); - if (sret < 0) + if (sret <= 0) goto error; if (scale[sret - 1] == '\n') @@ -360,7 +360,7 @@ static int perf_pmu__parse_unit(struct perf_pmu *pmu, struct perf_pmu_alias *ali return -1; sret = read(fd, alias->unit, UNIT_MAX_LEN); - if (sret < 0) + if (sret <= 0) goto error; close(fd); -- 2.53.0