linux-kernel - [PATCH AUTOSEL 4.14 051/123] efi: cper: Fix possible out-of-bounds access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20190327181628.15899-51-sashal@kernel.org>
Date:   Wed, 27 Mar 2019 14:15:15 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Ross Lagerwall <ross.lagerwall@...rix.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@...el.com>,
        Sasha Levin <sashal@...nel.org>, linux-efi@...r.kernel.org
Subject: [PATCH AUTOSEL 4.14 051/123] efi: cper: Fix possible out-of-bounds access

From: Ross Lagerwall <ross.lagerwall@...rix.com>

[ Upstream commit 45b14a4ffcc1e0b5caa246638f942cbe7eaea7ad ]

When checking a generic status block, we iterate over all the generic
data blocks. The loop condition only checks that the start of the
generic data block is valid (within estatus->data_length) but not the
whole block. Because the size of data blocks (excluding error data) may
vary depending on the revision and the revision is contained within the
data block, ensure that enough of the current data block is valid before
dereferencing any members otherwise an out-of-bounds access may occur if
estatus->data_length is invalid.

This relies on the fact that struct acpi_hest_generic_data_v300 is a
superset of the earlier version.  Also rework the other checks to avoid
potential underflow.

Signed-off-by: Ross Lagerwall <ross.lagerwall@...rix.com>
Acked-by: Borislav Petkov <bp@...e.de>
Tested-by: Tyler Baicar <baicar.tyler@...il.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/firmware/efi/cper.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c
index d2fcafcea07e..ce23d5402bd6 100644
--- a/drivers/firmware/efi/cper.c
+++ b/drivers/firmware/efi/cper.c
@@ -641,19 +641,24 @@ EXPORT_SYMBOL_GPL(cper_estatus_check_header);
 int cper_estatus_check(const struct acpi_hest_generic_status *estatus)
 {
 	struct acpi_hest_generic_data *gdata;
-	unsigned int data_len, gedata_len;
+	unsigned int data_len, record_size;
 	int rc;
 
 	rc = cper_estatus_check_header(estatus);
 	if (rc)
 		return rc;
+
 	data_len = estatus->data_length;
 
 	apei_estatus_for_each_section(estatus, gdata) {
-		gedata_len = acpi_hest_get_error_length(gdata);
-		if (gedata_len > data_len - acpi_hest_get_size(gdata))
+		if (sizeof(struct acpi_hest_generic_data) > data_len)
+			return -EINVAL;
+
+		record_size = acpi_hest_get_record_size(gdata);
+		if (record_size > data_len)
 			return -EINVAL;
-		data_len -= acpi_hest_get_record_size(gdata);
+
+		data_len -= record_size;
 	}
 	if (data_len)
 		return -EINVAL;
-- 
2.19.1