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From c9a71afe182be5b62bd2ccdaf861695e0ec0731a Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Mon, 18 Jan 2021 17:21:30 +0530
Subject: [PATCH] ide: atapi: check logical block address and read size
(CVE-2020-29443)
While processing ATAPI cmd_read/cmd_read_cd commands,
Logical Block Address (LBA) maybe invalid OR closer to the last block,
leading to an OOB access issues. Add range check to avoid it.
Fixes: CVE-2020-29443
Reported-by: Wenxiang Qian <leonwxqian@gmail.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
Message-Id: <20210118115130.457044-1-ppandit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Upstream-Status: Backport [b8d7f1bc59276fec85e4d09f1567613a3e14d31e]
CVE: CVE-2020-29443
Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
---
hw/ide/atapi.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c
index e79157863..b626199e3 100644
--- a/hw/ide/atapi.c
+++ b/hw/ide/atapi.c
@@ -322,6 +322,8 @@ static void ide_atapi_cmd_reply(IDEState *s, int size, int max_size)
static void ide_atapi_cmd_read_pio(IDEState *s, int lba, int nb_sectors,
int sector_size)
{
+ assert(0 <= lba && lba < (s->nb_sectors >> 2));
+
s->lba = lba;
s->packet_transfer_size = nb_sectors * sector_size;
s->elementary_transfer_size = 0;
@@ -420,6 +422,8 @@ eot:
static void ide_atapi_cmd_read_dma(IDEState *s, int lba, int nb_sectors,
int sector_size)
{
+ assert(0 <= lba && lba < (s->nb_sectors >> 2));
+
s->lba = lba;
s->packet_transfer_size = nb_sectors * sector_size;
s->io_buffer_size = 0;
@@ -973,35 +977,49 @@ static void cmd_prevent_allow_medium_removal(IDEState *s, uint8_t* buf)
static void cmd_read(IDEState *s, uint8_t* buf)
{
- int nb_sectors, lba;
+ unsigned int nb_sectors, lba;
+
+ /* Total logical sectors of ATAPI_SECTOR_SIZE(=2048) bytes */
+ uint64_t total_sectors = s->nb_sectors >> 2;
if (buf[0] == GPCMD_READ_10) {
nb_sectors = lduw_be_p(buf + 7);
} else {
nb_sectors = ldl_be_p(buf + 6);
}
-
- lba = ldl_be_p(buf + 2);
if (nb_sectors == 0) {
ide_atapi_cmd_ok(s);
return;
}
+ lba = ldl_be_p(buf + 2);
+ if (lba >= total_sectors || lba + nb_sectors - 1 >= total_sectors) {
+ ide_atapi_cmd_error(s, ILLEGAL_REQUEST, ASC_LOGICAL_BLOCK_OOR);
+ return;
+ }
+
ide_atapi_cmd_read(s, lba, nb_sectors, 2048);
}
static void cmd_read_cd(IDEState *s, uint8_t* buf)
{
- int nb_sectors, lba, transfer_request;
+ unsigned int nb_sectors, lba, transfer_request;
- nb_sectors = (buf[6] << 16) | (buf[7] << 8) | buf[8];
- lba = ldl_be_p(buf + 2);
+ /* Total logical sectors of ATAPI_SECTOR_SIZE(=2048) bytes */
+ uint64_t total_sectors = s->nb_sectors >> 2;
+ nb_sectors = (buf[6] << 16) | (buf[7] << 8) | buf[8];
if (nb_sectors == 0) {
ide_atapi_cmd_ok(s);
return;
}
+ lba = ldl_be_p(buf + 2);
+ if (lba >= total_sectors || lba + nb_sectors - 1 >= total_sectors) {
+ ide_atapi_cmd_error(s, ILLEGAL_REQUEST, ASC_LOGICAL_BLOCK_OOR);
+ return;
+ }
+
transfer_request = buf[9] & 0xf8;
if (transfer_request == 0x00) {
/* nothing */
--
2.29.2
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