linux-kernel - [PATCH] mmc: core: set read only with permanent write protect

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 22 Feb 2021 17:31:56 +0900
From:   Seunghui Lee <sh043.lee@...sung.com>
To:     ulf.hansson@...aro.org, pali@...nel.org, huyue2@...ong.com,
        tiantao6@...ilicon.com, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     grant.jung@...sung.com, jt77.jang@...sung.com,
        dh0421.hwang@...sung.com, junwoo80.lee@...sung.com,
        jangsub.yi@...sung.com, cw9316.lee@...sung.com,
        sh8267.baek@...sung.com, wkon.kim@...sung.com,
        Seunghui Lee <sh043.lee@...sung.com>
Subject: [PATCH] mmc: core: set read only with permanent write protect

Some of SD cards sets permanent write protection
due to lifespan or internal problem.
Host can find out it's protected permanantly during initialization.
Once set read only during initialization,
it could prevent unnecessary write operation in it.

Signed-off-by: Seunghui Lee <sh043.lee@...sung.com>
---
 drivers/mmc/core/sd.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 6fa51a6ed058..2c48d6504101 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -135,6 +135,9 @@ static int mmc_decode_csd(struct mmc_card *card)
 			csd->erase_size = UNSTUFF_BITS(resp, 39, 7) + 1;
 			csd->erase_size <<= csd->write_blkbits - 9;
 		}
+
+		if (UNSTUFF_BITS(resp, 13, 1))
+			mmc_card_set_readonly(card);
 		break;
 	case 1:
 		/*
@@ -169,6 +172,9 @@ static int mmc_decode_csd(struct mmc_card *card)
 		csd->write_blkbits = 9;
 		csd->write_partial = 0;
 		csd->erase_size = 1;
+
+		if (UNSTUFF_BITS(resp, 13, 1))
+			mmc_card_set_readonly(card);
 		break;
 	default:
 		pr_err("%s: unrecognised CSD structure version %d\n",
-- 
2.29.0