From 54309fde1a352ad2674ebba004a79f7d20b9f037 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20L=C3=B6hle?= <CLoehle@hyperstone.com>
Date: Fri, 4 Feb 2022 15:11:37 +0000
Subject: [PATCH] mmc: block: fix read single on recovery logic
Git-commit: 54309fde1a352ad2674ebba004a79f7d20b9f037
Patch-mainline: v5.17-rc5
References: CVE-2022-20008 bsc#1199564

On reads with MMC_READ_MULTIPLE_BLOCK that fail,
the recovery handler will use MMC_READ_SINGLE_BLOCK for
each of the blocks, up to MMC_READ_SINGLE_RETRIES times each.
The logic for this is fixed to never report unsuccessful reads
as success to the block layer.

On command error with retries remaining, blk_update_request was
called with whatever value error was set last to.
In case it was last set to BLK_STS_OK (default), the read will be
reported as success, even though there was no data read from the device.
This could happen on a CRC mismatch for the response,
a card rejecting the command (e.g. again due to a CRC mismatch).
In case it was last set to BLK_STS_IOERR, the error is reported correctly,
but no retries will be attempted.

Fixes: 81196976ed946c ("mmc: block: Add blk-mq support")
Cc: stable@vger.kernel.org
Signed-off-by: Christian Loehle <cloehle@hyperstone.com>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/bc706a6ab08c4fe2834ba0c05a804672@hyperstone.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/mmc/core/block.c |   28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1668,31 +1668,31 @@ static void mmc_blk_read_single(struct m
 	struct mmc_card *card = mq->card;
 	struct mmc_host *host = card->host;
 	blk_status_t error = BLK_STS_OK;
-	int retries = 0;
 
 	do {
 		u32 status;
 		int err;
+		int retries = 0;
 
-		mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
+		while (retries++ <= MMC_READ_SINGLE_RETRIES) {
+			mmc_blk_rw_rq_prep(mqrq, card, 1, mq);
 
-		mmc_wait_for_req(host, mrq);
+			mmc_wait_for_req(host, mrq);
 
-		err = mmc_send_status(card, &status);
-		if (err)
-			goto error_exit;
-
-		if (!mmc_host_is_spi(host) &&
-		    !mmc_blk_in_tran_state(status)) {
-			err = mmc_blk_fix_state(card, req);
+			err = mmc_send_status(card, &status);
 			if (err)
 				goto error_exit;
-		}
 
-		if (mrq->cmd->error && retries++ < MMC_READ_SINGLE_RETRIES)
-			continue;
+			if (!mmc_host_is_spi(host) &&
+			    !mmc_blk_in_tran_state(status)) {
+				err = mmc_blk_fix_state(card, req);
+				if (err)
+					goto error_exit;
+			}
 
-		retries = 0;
+			if (!mrq->cmd->error)
+				break;
+		}
 
 		if (mrq->cmd->error ||
 		    mrq->data->error ||