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 E2D5D3655CC; Wed, 10 Jun 2026 19:52:22 +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=1781121143; cv=none; b=O7/g2+Y6x3T/u1jWmTHtGXo/jJRFiF6aWbJcDmjSVG8u34Yzrd+SzPL+ouMdLf4U4OZMO9BrW7xELvmrCWcCEUvw31bIjUcKtjBKiUQkiL8JRtPZfh5xE7jQcdikRBHvhnSv0WioItTmFHyb28rqztNiQ2w4g14nnHbNP6zCzP8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781121143; c=relaxed/simple; bh=vShKGluurKkRKTjfEqQ1jrRKVLyvt1Ib/wLJjTl/CZ0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pilCikezNsemcIUQT/VMRQn+IGuwu4woVFGH+oYBv7BqhWdjcN84LF5STVGWAT5b+Zn9ib/Jm9vKWnUFEhBavppn47hDzqFZgoX8Hf4BTgmQ/cSW/hc5gAiX1lZtBQGBN0NjOZ9A2SkIELA7/0umZoRLCnvMYSrgfi24uZGkfMQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=h/Ngw9Mj; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="h/Ngw9Mj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1D891F00898; Wed, 10 Jun 2026 19:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781121142; bh=3srM3phoAEpQCJ2BEqrPS5BA0frGlkkEKdOHF2Ld/r8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=h/Ngw9MjYgv6zfgB2baCSrqgSt8KG99UFsRymgniIgKHRdirgG7esTXaRfGKXdnPR NVhtlclr4miWN/s5wes692qJKAjyziVG87xzQUt8dqSA9PZIA1vc4ISQf0h2m7p/Gk hoq3C7mDB5nyqF7D3dsS+7Uh98+XphjCrR5PSUVL8fHNcD3ReGVLqNZQs+f/Dm+vqJ d1Bh/SXAWHlLrfbSaRPWaiz0Ycud8iZqqZjxOZAoQI3Zjb0m8ZvaZIUO6f2IiVBwAC nkmacoIdrpu/R2LR/oJcrglPbfAnE0f/7G2IqHIrt+CzxsS0FhdgOZ8+7xyAtIEyWe 6iYm182ugo8/g== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot , "Claude Opus 4.6" Subject: [PATCH 03/23] tools lib api: Fix missing null termination in filename__read_int/ull() Date: Wed, 10 Jun 2026 16:51:36 -0300 Message-ID: <20260610195157.2091137-4-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260610195157.2091137-1-acme@kernel.org> References: <20260610195157.2091137-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo filename__read_int() passes a stack buffer to read() using the full sizeof(line) and then hands it to atoi() without null-terminating. If a sysfs file fills the 64-byte buffer exactly, atoi() reads past the array into uninitialized stack memory. filename__read_ull_base() has the same issue with strtoull(). Fix both by reading sizeof(line) - 1 bytes and explicitly null-terminating after a successful read. Fixes: 3a351127cbc682c3 ("tools lib fs: Adopt filename__read_int from tools/perf/") Reported-by: sashiko-bot Assisted-by: Claude Opus 4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/lib/api/fs/fs.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/tools/lib/api/fs/fs.c b/tools/lib/api/fs/fs.c index edec23406dbc619f..3cc302d4c47b1669 100644 --- a/tools/lib/api/fs/fs.c +++ b/tools/lib/api/fs/fs.c @@ -294,11 +294,14 @@ int filename__read_int(const char *filename, int *value) { char line[64]; int fd = open(filename, O_RDONLY), err = -1; + ssize_t n; if (fd < 0) return -errno; - if (read(fd, line, sizeof(line)) > 0) { + n = read(fd, line, sizeof(line) - 1); + if (n > 0) { + line[n] = '\0'; *value = atoi(line); err = 0; } @@ -312,11 +315,14 @@ static int filename__read_ull_base(const char *filename, { char line[64]; int fd = open(filename, O_RDONLY), err = -1; + ssize_t n; if (fd < 0) return -errno; - if (read(fd, line, sizeof(line)) > 0) { + n = read(fd, line, sizeof(line) - 1); + if (n > 0) { + line[n] = '\0'; *value = strtoull(line, NULL, base); if (*value != ULLONG_MAX) err = 0; -- 2.54.0