Bufferoverflow on eMMC partition handling

[Sascha Hauer]

On Fri, Sep 06, 2024 at 08:28:26AM +0200, Florian Otte wrote:
> Hey Sascha,
> 
> thank your for your reply. I am a little bit unfamiliar with the
> processes, so I hope this is what your are asking for.

Indeed, that's what I was asking for. All good now, patch applied,
thanks

Sascha

> 
> Kind Regards,
> Florian
> 
> 
> 
> On Tuesday, September 03, 2024 13:38 CEST, Sascha Hauer <s.hauer at pengutronix.de> wrote:
> 
> > On Mon, Sep 02, 2024 at 11:37:56AM +0200, Florian Otte wrote:
> > > Hi Everyone.
> > > 
> > > I tried to use all general purpose partitions on an eMMC storage
> > > device and ran into some trouble. In ./include/mci.h the number of
> > > partitions is limited to 6, but there might be 7 partitions. This
> > > results in a buffer overflow or access out of bound and causes a nasty
> > > bootloop when all general purpose-partitions are used. I created a
> > > simple patch and appended it to this mail.
> > > 
> > > Kind regards
> > > fotte
> > > 
> > > [Edit]: Sorry. Clicked the wrong button to fast. Now with Attachment.
> > 
> > > From 0bae0df23bbc4a9e98f1bcac6c6fbe0c3b21bc78 Mon Sep 17 00:00:00 2001
> > > From: Florian Otte <fotte at uos.de>
> > > Date: Mon, 2 Sep 2024 11:27:47 +0200
> > > Subject: [PATCH] FIX: buffer overflow on MCI-partition enumeration
> > > 
> > > Memory for up to 6 partitions is reserved, however there can be up to 7
> > > partitions on an mci storage (e.g. emmc). A user partition two boot partitions
> > > and up to four general pupose partitions.
> > > ---
> > >  include/mci.h | 5 ++++-
> > >  1 file changed, 4 insertions(+), 1 deletion(-)
> > 
> > Your patch lacks a Signed-off-by: line. Please respond with such a line.
> > 
> > Otherwise ok, thanks for fixing this. I additionally created a patch to
> > check for the array boundaries.
> > 
> > Sascha
> > 
> > -- 
> > Pengutronix e.K.                           |                             |
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> From e5121cb2ae2a2d4294cafb93ec30abf6b7bcd0c1 Mon Sep 17 00:00:00 2001
> From: Florian Otte <fotte at uos.de>
> Date: Mon, 2 Sep 2024 11:27:47 +0200
> Subject: [PATCH] FIX: buffer overflow on MCI-partition enumeration
> 
> Memory for up to 6 partitions is reserved, however there can be up to 7
> partitions on an mci storage (e.g. emmc). A user partition two boot partitions
> and up to four general pupose partitions.
> 
> Signed-off-by: Florian.Otte <fotte at uos.de>
> ---
>  include/mci.h | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/include/mci.h b/include/mci.h
> index 3bf1455a40..cd01e2f992 100644
> --- a/include/mci.h
> +++ b/include/mci.h
> @@ -600,7 +600,10 @@ struct mci_host {
>  
>  #define MMC_NUM_BOOT_PARTITION	2
>  #define MMC_NUM_GP_PARTITION	4
> -#define MMC_NUM_PHY_PARTITION	6
> +#define MMC_NUM_USER_PARTITION	1
> +#define MMC_NUM_PHY_PARTITION	(MMC_NUM_BOOT_PARTITION + \
> +                                 MMC_NUM_GP_PARTITION + \
> +                                 MMC_NUM_USER_PARTITION)
>  
>  struct mci_part {
>  	struct block_device	blk;		/**< the blockdevice for the card */
> -- 
> 2.39.2
> 
> 


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