From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2ACB479DAB; Wed, 21 Feb 2024 13:30:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708522233; cv=none; b=X5fGe5x43A//hK+Yqqc4pqJkQGTRuYMQXsTGWem26d+zZRM/euG57ahN5Jat6nU4yAO+xx93sxtNCHBCNMmM0YRLhhcvVaQzhpyJlwLms3gdc0fJpG4VgbU7DNHbZuISg4d300E9TZYLXtLQXzFzSFyBC62u8UAU9ZYTYOHalQU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708522233; c=relaxed/simple; bh=S0NnrlO3UpWjqIsyP4x1dcIF5OEjRb0Y0RNtXnonzjw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c0cFRVPNC5MV3Df7oNDyX+zbqyUq20vpd2113/A7gis7O1NJP189msQccqkHJ00Dd6xiGSwJ/LbafoRtzVFFL5hsXChxaEdGI3awdXyWFeOvriOUAGEHLTrBYRoPRABpKekMvh0Y/02L1Jnl2qwyHwBwqLSfw7V+jBj2KL3CIqo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2LC1gR2k; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2LC1gR2k" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 86961C433B1; Wed, 21 Feb 2024 13:30:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708522233; bh=S0NnrlO3UpWjqIsyP4x1dcIF5OEjRb0Y0RNtXnonzjw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2LC1gR2ku28r1rHcYviKF45nq8gQke5nIh31M8WNZT6OW3u5PRb/sXlls2PM0mw54 h41iAcHoECLks9iK2tU9vyksAnZ5Gh1masrJriFhn/32E5llkPPzkzhE5OsBAUz3jy lQ11dcgAtumzxLGIoiJtir5KC2xOxi99WF30QIKE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christian Marangi , Chanwoo Choi , Sasha Levin Subject: [PATCH 5.15 109/476] PM / devfreq: Fix buffer overflow in trans_stat_show Date: Wed, 21 Feb 2024 14:02:40 +0100 Message-ID: <20240221130011.999916709@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240221130007.738356493@linuxfoundation.org> References: <20240221130007.738356493@linuxfoundation.org> User-Agent: quilt/0.67 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-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Christian Marangi [ Upstream commit 08e23d05fa6dc4fc13da0ccf09defdd4bbc92ff4 ] Fix buffer overflow in trans_stat_show(). Convert simple snprintf to the more secure scnprintf with size of PAGE_SIZE. Add condition checking if we are exceeding PAGE_SIZE and exit early from loop. Also add at the end a warning that we exceeded PAGE_SIZE and that stats is disabled. Return -EFBIG in the case where we don't have enough space to write the full transition table. Also document in the ABI that this function can return -EFBIG error. Link: https://lore.kernel.org/all/20231024183016.14648-2-ansuelsmth@gmail.com/ Cc: stable@vger.kernel.org Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218041 Fixes: e552bbaf5b98 ("PM / devfreq: Add sysfs node for representing frequency transition information.") Signed-off-by: Christian Marangi Signed-off-by: Chanwoo Choi Signed-off-by: Sasha Levin --- Documentation/ABI/testing/sysfs-class-devfreq | 3 + drivers/devfreq/devfreq.c | 59 +++++++++++++++++--------- 2 files changed, 43 insertions(+), 19 deletions(-) --- a/Documentation/ABI/testing/sysfs-class-devfreq +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -52,6 +52,9 @@ Description: echo 0 > /sys/class/devfreq/.../trans_stat + If the transition table is bigger than PAGE_SIZE, reading + this will return an -EFBIG error. + What: /sys/class/devfreq/.../available_frequencies Date: October 2012 Contact: Nishanth Menon --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -1653,7 +1653,7 @@ static ssize_t trans_stat_show(struct de struct device_attribute *attr, char *buf) { struct devfreq *df = to_devfreq(dev); - ssize_t len; + ssize_t len = 0; int i, j; unsigned int max_state; @@ -1662,7 +1662,7 @@ static ssize_t trans_stat_show(struct de max_state = df->profile->max_state; if (max_state == 0) - return sprintf(buf, "Not Supported.\n"); + return scnprintf(buf, PAGE_SIZE, "Not Supported.\n"); mutex_lock(&df->lock); if (!df->stop_polling && @@ -1672,33 +1672,54 @@ static ssize_t trans_stat_show(struct de } mutex_unlock(&df->lock); - len = sprintf(buf, " From : To\n"); - len += sprintf(buf + len, " :"); - for (i = 0; i < max_state; i++) - len += sprintf(buf + len, "%10lu", - df->profile->freq_table[i]); + len += scnprintf(buf + len, PAGE_SIZE - len, " From : To\n"); + len += scnprintf(buf + len, PAGE_SIZE - len, " :"); + for (i = 0; i < max_state; i++) { + if (len >= PAGE_SIZE - 1) + break; + len += scnprintf(buf + len, PAGE_SIZE - len, "%10lu", + df->profile->freq_table[i]); + } + if (len >= PAGE_SIZE - 1) + return PAGE_SIZE - 1; - len += sprintf(buf + len, " time(ms)\n"); + len += scnprintf(buf + len, PAGE_SIZE - len, " time(ms)\n"); for (i = 0; i < max_state; i++) { + if (len >= PAGE_SIZE - 1) + break; if (df->profile->freq_table[i] == df->previous_freq) { - len += sprintf(buf + len, "*"); + len += scnprintf(buf + len, PAGE_SIZE - len, "*"); } else { - len += sprintf(buf + len, " "); + len += scnprintf(buf + len, PAGE_SIZE - len, " "); } - len += sprintf(buf + len, "%10lu:", - df->profile->freq_table[i]); - for (j = 0; j < max_state; j++) - len += sprintf(buf + len, "%10u", - df->stats.trans_table[(i * max_state) + j]); + if (len >= PAGE_SIZE - 1) + break; + + len += scnprintf(buf + len, PAGE_SIZE - len, "%10lu:", + df->profile->freq_table[i]); + for (j = 0; j < max_state; j++) { + if (len >= PAGE_SIZE - 1) + break; + len += scnprintf(buf + len, PAGE_SIZE - len, "%10u", + df->stats.trans_table[(i * max_state) + j]); + } + if (len >= PAGE_SIZE - 1) + break; + len += scnprintf(buf + len, PAGE_SIZE - len, "%10llu\n", (u64) + jiffies64_to_msecs(df->stats.time_in_state[i])); + } - len += sprintf(buf + len, "%10llu\n", (u64) - jiffies64_to_msecs(df->stats.time_in_state[i])); + if (len < PAGE_SIZE - 1) + len += scnprintf(buf + len, PAGE_SIZE - len, "Total transition : %u\n", + df->stats.total_trans); + + if (len >= PAGE_SIZE - 1) { + pr_warn_once("devfreq transition table exceeds PAGE_SIZE. Disabling\n"); + return -EFBIG; } - len += sprintf(buf + len, "Total transition : %u\n", - df->stats.total_trans); return len; }