linux-kernel - Re: [PATCH] mmc: card: Don't show eMMC RPMB and BOOT areas in /proc/partitions

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Message-ID: <14AC9066-4BA9-478D-9F67-2A29D69E6011@wdc.com>
Date:   Tue, 27 Feb 2018 14:58:33 +0000
From:   Alex Lemberg <Alex.Lemberg@....com>
To:     Harish Jenny K N <harish_kandiga@...tor.com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
        "linus.walleij@...aro.org" <linus.walleij@...aro.org>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "shawn.lin@...k-chips.com" <shawn.lin@...k-chips.com>
CC:     "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mmc: card: Don't show eMMC RPMB and BOOT areas in
 /proc/partitions

Hi Andrew,

While RPMB partition requires special IOCTL, the boot partition is only requires "switch partition", which is not unusual operation in eMMC.
Why to prevent users access boot partition?

Thanks,
Alex 

On 2/27/18, 1:34 PM, "linux-mmc-owner@...r.kernel.org on behalf of Harish Jenny K N" <linux-mmc-owner@...r.kernel.org on behalf of harish_kandiga@...tor.com> wrote:

    From: Andrew Gabbasov <andrew_gabbasov@...tor.com>
    
    Since RPMB area is accessible via special ioctl only and boot areas
    are unlikely to contain any partitions, exclude them all from listing
    in /proc/partitions. This will hide them from various user-level
    software (e.g. fdisk), thus avoiding unnecessary access attempts.
    
    Signed-off-by: Andrew Gabbasov <andrew_gabbasov@...tor.com>
    Signed-off-by: Harish Jenny K N <harish_kandiga@...tor.com>
    ---
     drivers/mmc/core/block.c | 3 ++-
     1 file changed, 2 insertions(+), 1 deletion(-)
    
    diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
    index 20135a5..376e47e 100644
    --- a/drivers/mmc/core/block.c
    +++ b/drivers/mmc/core/block.c
    @@ -2341,7 +2341,8 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card,
     	set_disk_ro(md->disk, md->read_only || default_ro);
     	md->disk->flags = GENHD_FL_EXT_DEVT;
     	if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT))
    -		md->disk->flags |= GENHD_FL_NO_PART_SCAN;
    +		md->disk->flags |= GENHD_FL_NO_PART_SCAN
    +				   | GENHD_FL_SUPPRESS_PARTITION_INFO;
     
     	/*
     	 * As discussed on lkml, GENHD_FL_REMOVABLE should:
    -- 
    1.9.1
    
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