From: "Christian A. Ehrhardt" Date: Mon, 24 Oct 2022 17:42:33 +0200 Subject: [PATCH] hw/acpi/erst.c: Fix memory handling issues - 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 Cc: qemu-stable@nongnu.org Fixes: f7e26ffa590 ("ACPI ERST: support for ACPI ERST feature") Tested-by: Alexander Bulekov Signed-off-by: Christian A. Ehrhardt Message-Id: <20221024154233.1043347-1-lk@c--e.de> Fixes: https://gitlab.com/qemu-project/qemu/-/issues/1268 Reviewed-by: Alexander Bulekov Reviewed-by: Eric DeVolder Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- 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 de509c2b48..f092ce4d49 100644 --- a/hw/acpi/erst.c +++ b/hw/acpi/erst.c @@ -632,7 +632,7 @@ 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 */ @@ -681,7 +681,7 @@ 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; } @@ -713,7 +713,7 @@ 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;