[U-Boot] [PATCH] part_dos: check status flags of partitions

[Daniel Mack]

ping?

On Mon, Sep 28, 2009 at 12:04:00PM +0200, Daniel Mack wrote:
> The current fatload code has a problem together with the way the DOS
> partition parser is implemented.
> 
> This hit me when I tried to load a file from a USB stick which had no
> partition table but a FAT16 directly written to the first sector.
> 
> With such an environment, get_partition_info_extended() still finds a
> valid partition at the first sector since the 0x55aa magic is valid for
> both the MBR and the FAT boot sector.
> 
> As a result, part_offset in fs/fat/fat.c is then set to some ridiculous
> value and the code searching for the directory entry gets lots in an
> endless loop.
> 
> The fix is quite simple though - we just need to check the status field
> of the partitions more stricly. According to the specs, it may only
> contain 0x00 and 0x80. If get_partition_info() fails for this case, the
> fatload code falls back to the assumption that there is no partition
> table and does the right thing then.
> 
> Please consider applying the following patch.
> 
> Daniel
> 
> 
> From 381a85bf04adc228cc70e8fa7af899a6dbf07e42 Mon Sep 17 00:00:00 2001
> From: Daniel Mack <daniel at caiaq.de>
> Date: Mon, 28 Sep 2009 11:40:38 +0200
> Subject: [PATCH] part_dos: check status flags of partitions
> 
> Only read partitions which have 0x00 or 0x80 set in their status field.
> All others are invalid.
> 
> Signed-off-by: Daniel Mack <daniel at caiaq.de>
> ---
>  disk/part_dos.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/disk/part_dos.c b/disk/part_dos.c
> index 93bf3dd..e32d58e 100644
> --- a/disk/part_dos.c
> +++ b/disk/part_dos.c
> @@ -188,7 +188,8 @@ static int get_partition_info_extended (block_dev_desc_t *dev_desc, int ext_part
>  		 * fdisk does not show the extended partitions that
>  		 * are not in the MBR
>  		 */
> -		if ((pt->sys_ind != 0) &&
> +		if (((pt->boot_ind & ~0x80) == 0) &&
> +		    (pt->sys_ind != 0) &&
>  		    (part_num == which_part) &&
>  		    (is_extended(pt->sys_ind) == 0)) {
>  			info->blksz = 512;
> -- 
> 1.6.3.3
>