File hw-sd-sdcard-Do-not-switch-to-ReceivingD.patch of Package qemu.28164
From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <f4bug@amsat.org>
Date: Thu, 4 Jun 2020 19:22:29 +0200
Subject: hw/sd/sdcard: Do not switch to ReceivingData if address is invalid
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Git-commit: 790762e5487114341cccc5bffcec4cb3c022c3cd
References: bsc#1172033 CVE-2020-13253
Only move the state machine to ReceivingData if there is no
pending error. This avoids later OOB access while processing
commands queued.
"SD Specifications Part 1 Physical Layer Simplified Spec. v3.01"
4.3.3 Data Read
Read command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR
occurred and no data transfer is performed.
4.3.4 Data Write
Write command is rejected if BLOCK_LEN_ERROR or ADDRESS_ERROR
occurred and no data transfer is performed.
WP_VIOLATION errors are not modified: the error bit is set, we
stay in receive-data state, wait for a stop command. All further
data transfer is ignored. See the check on sd->card_status at the
beginning of sd_read_data() and sd_write_data().
Fixes: CVE-2020-13253
Cc: qemu-stable@nongnu.org
Reported-by: Alexander Bulekov <alxndr@bu.edu>
Buglink: https://bugs.launchpad.net/qemu/+bug/1880822
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20200630133912.9428-6-f4bug@amsat.org>
---
hw/sd/sd.c | 38 ++++++++++++++++++++++++--------------
1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/hw/sd/sd.c b/hw/sd/sd.c
index adb372a8a57371c13b68931b493e..8d8b6894416c35d969734bd1ca5b 100644
--- a/hw/sd/sd.c
+++ b/hw/sd/sd.c
@@ -1150,13 +1150,15 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
case 17: /* CMD17: READ_SINGLE_BLOCK */
switch (sd->state) {
case sd_transfer_state:
- sd->state = sd_sendingdata_state;
- sd->data_start = addr;
- sd->data_offset = 0;
- if (sd->data_start + sd->blk_len > sd->size) {
+ if (addr + sd->blk_len > sd->size) {
sd->card_status |= ADDRESS_ERROR;
+ return sd_r1;
}
+
+ sd->state = sd_sendingdata_state;
+ sd->data_start = addr;
+ sd->data_offset = 0;
return sd_r1;
default:
@@ -1167,13 +1169,15 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
case 18: /* CMD18: READ_MULTIPLE_BLOCK */
switch (sd->state) {
case sd_transfer_state:
- sd->state = sd_sendingdata_state;
- sd->data_start = addr;
- sd->data_offset = 0;
- if (sd->data_start + sd->blk_len > sd->size) {
+ if (addr + sd->blk_len > sd->size) {
sd->card_status |= ADDRESS_ERROR;
+ return sd_r1;
}
+
+ sd->state = sd_sendingdata_state;
+ sd->data_start = addr;
+ sd->data_offset = 0;
return sd_r1;
default:
@@ -1213,14 +1217,17 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
/* Writing in SPI mode not implemented. */
if (sd->spi)
break;
+
+ if (addr + sd->blk_len > sd->size) {
+ sd->card_status |= ADDRESS_ERROR;
+ return sd_r1;
+ }
+
sd->state = sd_receivingdata_state;
sd->data_start = addr;
sd->data_offset = 0;
sd->blk_written = 0;
- if (sd->data_start + sd->blk_len > sd->size) {
- sd->card_status |= ADDRESS_ERROR;
- }
if (sd_wp_addr(sd, sd->data_start)) {
sd->card_status |= WP_VIOLATION;
}
@@ -1240,14 +1247,17 @@ static sd_rsp_type_t sd_normal_command(SDState *sd, SDRequest req)
/* Writing in SPI mode not implemented. */
if (sd->spi)
break;
+
+ if (addr + sd->blk_len > sd->size) {
+ sd->card_status |= ADDRESS_ERROR;
+ return sd_r1;
+ }
+
sd->state = sd_receivingdata_state;
sd->data_start = addr;
sd->data_offset = 0;
sd->blk_written = 0;
- if (sd->data_start + sd->blk_len > sd->size) {
- sd->card_status |= ADDRESS_ERROR;
- }
if (sd_wp_addr(sd, sd->data_start)) {
sd->card_status |= WP_VIOLATION;
}