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Tue, 10 Dec 2024 22:26:22 +0000 Received: from smtpav04.wdc07v.mail.ibm.com (smtpav04.wdc07v.mail.ibm.com [10.39.53.231]) by smtprelay04.dal12v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 4BAMQMQo17760832 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 10 Dec 2024 22:26:22 GMT Received: from smtpav04.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E1BA458052; Tue, 10 Dec 2024 22:26:21 +0000 (GMT) Received: from smtpav04.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4D35158054; Tue, 10 Dec 2024 22:26:21 +0000 (GMT) Received: from sbct-3.pok.ibm.com (unknown [9.47.158.153]) by smtpav04.wdc07v.mail.ibm.com (Postfix) with ESMTP; Tue, 10 Dec 2024 22:26:21 +0000 (GMT) From: Stefan Berger To: linux-integrity@vger.kernel.org, jarkko@kernel.org Cc: linux-kernel@vger.kernel.org, Stefan Berger , Andy Liang , Takashi Iwai Subject: [PATCH] tpm/eventlog: Limit memory allocations for event logs with excessive size Date: Tue, 10 Dec 2024 17:26:08 -0500 Message-ID: <20241210222608.598424-1-stefanb@linux.ibm.com> X-Mailer: git-send-email 2.47.1 Precedence: bulk X-Mailing-List: linux-integrity@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: fko00RqIkJ3ZBmeBtyrGZ37_2ubZdB0d X-Proofpoint-ORIG-GUID: fko00RqIkJ3ZBmeBtyrGZ37_2ubZdB0d X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-10-15_01,2024-10-11_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 suspectscore=0 spamscore=0 clxscore=1015 priorityscore=1501 lowpriorityscore=0 impostorscore=0 bulkscore=0 mlxscore=0 malwarescore=0 mlxlogscore=999 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2412100157 The TPM2 ACPI BIOS eventlog of a particular machine indicates that the length of the log is 4MB, even though the actual length of its useful data, when dumped, are only 69kb. To avoid allocating excessive amounts of memory for the event log, limit the size of any eventlog to 128kb. This should be sufficient memory and also not unnecessarily truncate event logs on any other machine. Reported-by: Andy Liang Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219495 Cc: Takashi Iwai Signed-off-by: Stefan Berger --- drivers/char/tpm/eventlog/acpi.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/char/tpm/eventlog/acpi.c b/drivers/char/tpm/eventlog/acpi.c index 69533d0bfb51..701fd7d4cc28 100644 --- a/drivers/char/tpm/eventlog/acpi.c +++ b/drivers/char/tpm/eventlog/acpi.c @@ -26,6 +26,8 @@ #include "../tpm.h" #include "common.h" +#define MAX_TPM_LOG_LEN (128 * 1024) + struct acpi_tcpa { struct acpi_table_header hdr; u16 platform_class; @@ -135,6 +137,12 @@ int tpm_read_log_acpi(struct tpm_chip *chip) return -EIO; } + if (len > MAX_TPM_LOG_LEN) { + dev_warn(&chip->dev, "Excessive TCPA log len %llu truncated to %u bytes\n", + len, MAX_TPM_LOG_LEN); + len = MAX_TPM_LOG_LEN; + } + /* malloc EventLog space */ log->bios_event_log = devm_kmalloc(&chip->dev, len, GFP_KERNEL); if (!log->bios_event_log)