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hw/sd/sdcard: Do not switch to ReceivingData if address is invalid

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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>
This commit is contained in:
Philippe Mathieu-Daudé 2020-06-04 19:22:29 +02:00
parent 794d68de2f
commit 790762e548
1 changed files with 24 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
hw/sd/sd.c
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@ -1171,13 +1171,15 @@ 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:
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;
if (sd->data_start + sd->blk_len > sd->size) {
sd->card_status |= ADDRESS_ERROR;
}
return sd_r1;
default:
@ -1188,13 +1190,15 @@ 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:
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;
if (sd->data_start + sd->blk_len > sd->size) {
sd->card_status |= ADDRESS_ERROR;
}
return sd_r1;
default:
@ -1234,14 +1238,17 @@ 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;
}
@ -1261,14 +1268,17 @@ 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;
}