[PATCHv3 1/1] mmc: block: ioctl: Add PROG-error aggregation

From: Christian Loehle
Date: Tue Jun 20 2023 - 08:44:50 EST

Userspace currently has no way of checking for error bits of
detection mode X. These are error bits that are only detected by
the card when executing the command. For e.g. a sanitize operation
this may be minutes after the RSP was seen by the host.

Currently userspace programs cannot see these error bits reliably.
They could issue a multi ioctl cmd with a CMD13 immediately following
it, but since errors of detection mode X are automatically cleared
(they are all clear condition B).
mmc_poll_for_busy of the first ioctl may have already hidden such an
error flag.

In case of the security operations: sanitize, secure erases and
RPMB writes, this could lead to the operation not being performed
successfully by the card with the user not knowing.
If the user trusts that this operation is completed
(e.g. their data is sanitized), this could be a security issue.
An attacker could e.g. provoke a eMMC (VCC) flash fail, where a
successful sanitize of a card is not possible. A card may move out
of PROG state but issue a bit 19 R1 error.

This patch therefore will also have the consequence of a mmc-utils
patch, which enables the bit for the security-sensitive operations.

Signed-off-by: Christian Loehle <cloehle@xxxxxxxxxxxxxx>
---
drivers/mmc/core/block.c | 26 +++++++++++++++-----------
drivers/mmc/core/mmc_ops.c | 14 +++++++-------
drivers/mmc/core/mmc_ops.h | 9 +++++++++
3 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index e46330815484..c7e2b8ae58a9 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -470,7 +470,7 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
struct mmc_data data = {};
struct mmc_request mrq = {};
struct scatterlist sg;
- bool r1b_resp, use_r1b_resp = false;
+ bool r1b_resp;
unsigned int busy_timeout_ms;
int err;
unsigned int target_part;
@@ -551,8 +551,7 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
busy_timeout_ms = idata->ic.cmd_timeout_ms ? : MMC_BLK_TIMEOUT_MS;
r1b_resp = (cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B;
if (r1b_resp)
- use_r1b_resp = mmc_prepare_busy_cmd(card->host, &cmd,
- busy_timeout_ms);
+ mmc_prepare_busy_cmd(card->host, &cmd, busy_timeout_ms);

mmc_wait_for_req(card->host, &mrq);
memcpy(&idata->ic.response, cmd.resp, sizeof(cmd.resp));
@@ -605,19 +604,24 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct mmc_blk_data *md,
if (idata->ic.postsleep_min_us)
usleep_range(idata->ic.postsleep_min_us, idata->ic.postsleep_max_us);

- /* No need to poll when using HW busy detection. */
- if ((card->host->caps & MMC_CAP_WAIT_WHILE_BUSY) && use_r1b_resp)
- return 0;
-
if (mmc_host_is_spi(card->host)) {
if (idata->ic.write_flag || r1b_resp || cmd.flags & MMC_RSP_SPI_BUSY)
return mmc_spi_err_check(card);
return err;
}
- /* Ensure RPMB/R1B command has completed by polling with CMD13. */
- if (idata->rpmb || r1b_resp)
- err = mmc_poll_for_busy(card, busy_timeout_ms, false,
- MMC_BUSY_IO);
+ /* Poll for RPMB/write/R1B execution errors */
+ if (idata->rpmb || idata->ic.write_flag || r1b_resp) {
+ struct mmc_busy_data cb_data;
+
+ cb_data.card = card;
+ cb_data.retry_crc_err = false;
+ cb_data.aggregate_err_flags = true;
+ cb_data.busy_cmd = MMC_BUSY_IO;
+ cb_data.status = &idata->ic.response[0];
+ err = __mmc_poll_for_busy(card->host, 0, busy_timeout_ms,
+ &mmc_busy_cb, &cb_data);
+
+ }

return err;
}
diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 3b3adbddf664..15d8b806c670 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -54,11 +54,6 @@ static const u8 tuning_blk_pattern_8bit[] = {
0xff, 0x77, 0x77, 0xff, 0x77, 0xbb, 0xdd, 0xee,
};

-struct mmc_busy_data {
- struct mmc_card *card;
- bool retry_crc_err;
- enum mmc_busy_cmd busy_cmd;
-};

struct mmc_op_cond_busy_data {
struct mmc_host *host;
@@ -457,14 +452,15 @@ int mmc_switch_status(struct mmc_card *card, bool crc_err_fatal)
return mmc_switch_status_error(card->host, status);
}

-static int mmc_busy_cb(void *cb_data, bool *busy)
+int mmc_busy_cb(void *cb_data, bool *busy)
{
struct mmc_busy_data *data = cb_data;
struct mmc_host *host = data->card->host;
u32 status = 0;
int err;

- if (data->busy_cmd != MMC_BUSY_IO && host->ops->card_busy) {
+ if (data->busy_cmd != MMC_BUSY_IO && host->ops->card_busy &&
+ !data->aggregate_err_flags) {
*busy = host->ops->card_busy(host);
return 0;
}
@@ -477,6 +473,9 @@ static int mmc_busy_cb(void *cb_data, bool *busy)
if (err)
return err;

+ if (data->aggregate_err_flags)
+ *data->status = R1_STATUS(*data->status) | status;
+
switch (data->busy_cmd) {
case MMC_BUSY_CMD6:
err = mmc_switch_status_error(host, status);
@@ -549,6 +548,7 @@ int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,

cb_data.card = card;
cb_data.retry_crc_err = retry_crc_err;
+ cb_data.aggregate_err_flags = false;
cb_data.busy_cmd = busy_cmd;

return __mmc_poll_for_busy(host, 0, timeout_ms, &mmc_busy_cb, &cb_data);
diff --git a/drivers/mmc/core/mmc_ops.h b/drivers/mmc/core/mmc_ops.h
index 09ffbc00908b..a57751b83f19 100644
--- a/drivers/mmc/core/mmc_ops.h
+++ b/drivers/mmc/core/mmc_ops.h
@@ -18,6 +18,14 @@ enum mmc_busy_cmd {
MMC_BUSY_IO,
};

+struct mmc_busy_data {
+ struct mmc_card *card;
+ bool retry_crc_err;
+ bool aggregate_err_flags;
+ enum mmc_busy_cmd busy_cmd;
+ u32 *status;
+};
+
struct mmc_host;
struct mmc_card;
struct mmc_command;
@@ -41,6 +49,7 @@ int mmc_can_ext_csd(struct mmc_card *card);
int mmc_switch_status(struct mmc_card *card, bool crc_err_fatal);
bool mmc_prepare_busy_cmd(struct mmc_host *host, struct mmc_command *cmd,
unsigned int timeout_ms);
+int mmc_busy_cb(void *cb_data, bool *busy);
int __mmc_poll_for_busy(struct mmc_host *host, unsigned int period_us,
unsigned int timeout_ms,
int (*busy_cb)(void *cb_data, bool *busy),
--
2.37.3

Attachment: smime.p7s
Description: S/MIME cryptographic signature