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From: "Christian A. Ehrhardt" <lk@c--e.de>
To: qemu-devel@nongnu.org
Cc: "Christian A. Ehrhardt" <lk@c--e.de>,
	"Alexander Bulekov" <alxndr@bu.edu>,
	qemu-stable@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
	"Igor Mammedov" <imammedo@redhat.com>,
	"Ani Sinha" <ani@anisinha.ca>,
	"Eric DeVolder" <eric.devolder@oracle.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>
Subject: [PATCH v2] hw/acpi/erst.c: Fix memory handling issues
Date: Mon, 24 Oct 2022 17:42:33 +0200	[thread overview]
Message-ID: <20221024154233.1043347-1-lk@c--e.de> (raw)
In-Reply-To: <20221024100323-mutt-send-email-mst@kernel.org>

- Fix memset argument order: The second argument is
  the value, the length goes last.
- Fix an integer overflow reported by Alexander Bulekov.

Both issues allow the guest to overrun the host buffer
allocated for the ERST memory device.

Cc: Eric DeVolder <eric.devolder@oracle.com
Cc: Alexander Bulekov <alxndr@bu.edu>
Cc: qemu-stable@nongnu.org
Fixes: f7e26ffa590 ("ACPI ERST: support for ACPI ERST feature")
Tested-by: Alexander Bulekov <alxndr@bu.edu>
Signed-off-by: Christian A. Ehrhardt <lk@c--e.de>
---
 hw/acpi/erst.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/acpi/erst.c b/hw/acpi/erst.c
index df856b2669..aefcc03ad6 100644
--- a/hw/acpi/erst.c
+++ b/hw/acpi/erst.c
@@ -635,7 +635,7 @@ static unsigned read_erst_record(ERSTDeviceState *s)
         if (record_length < UEFI_CPER_RECORD_MIN_SIZE) {
             rc = STATUS_FAILED;
         }
-        if ((s->record_offset + record_length) > exchange_length) {
+        if (record_length > exchange_length - s->record_offset) {
             rc = STATUS_FAILED;
         }
         /* If all is ok, copy the record to the exchange buffer */
@@ -684,7 +684,7 @@ static unsigned write_erst_record(ERSTDeviceState *s)
     if (record_length < UEFI_CPER_RECORD_MIN_SIZE) {
         return STATUS_FAILED;
     }
-    if ((s->record_offset + record_length) > exchange_length) {
+    if (record_length > exchange_length - s->record_offset) {
         return STATUS_FAILED;
     }
 
@@ -716,7 +716,7 @@ static unsigned write_erst_record(ERSTDeviceState *s)
     if (nvram) {
         /* Write the record into the slot */
         memcpy(nvram, exchange, record_length);
-        memset(nvram + record_length, exchange_length - record_length, 0xFF);
+        memset(nvram + record_length, 0xFF, exchange_length - record_length);
         /* If a new record, increment the record_count */
         if (!record_found) {
             uint32_t record_count;
-- 
2.34.1



  reply	other threads:[~2022-10-24 16:09 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-19 19:15 [PATCH] hw/acpi/erst.c: Fix memset argument order Christian A. Ehrhardt
2022-10-19 19:37 ` Philippe Mathieu-Daudé
2022-10-19 19:45   ` Eric DeVolder
2022-10-20  6:14 ` Markus Armbruster
2022-10-20 19:58   ` Christian A. Ehrhardt
2022-10-21  4:22     ` Markus Armbruster
2022-10-21  6:42       ` Christian A. Ehrhardt
2022-10-21 15:29   ` Eric DeVolder
2022-10-21 19:05 ` Alexander Bulekov
2022-10-22  5:37   ` Alexander Bulekov
2022-10-23 14:37     ` Christian A. Ehrhardt
2022-10-24 13:20       ` Alexander Bulekov
2022-10-24 14:04         ` Michael S. Tsirkin
2022-10-24 15:42           ` Christian A. Ehrhardt [this message]
2022-10-24 16:24             ` [PATCH v2] hw/acpi/erst.c: Fix memory handling issues Alexander Bulekov
2022-10-25  0:24               ` Alexander Bulekov
2022-10-24 20:34             ` Eric DeVolder
2022-10-24 20:37             ` Michael S. Tsirkin

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