From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anatolij Gustschin Date: Sat, 12 May 2012 17:41:13 +0200 Subject: [U-Boot] [PATCH 1/1] fat: FAT sector offsets overflow on large disks and/or FAT partitions In-Reply-To: <4FA1EAC5.8000003@cavium.com> References: <4FA1EAC5.8000003@cavium.com> Message-ID: <20120512174113.70f48f08@wker> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hello, On Wed, 02 May 2012 19:17:41 -0700 Aaron Williams wrote: > This patch fixes several issues where sector offsets can overflow due to > being limited to 16-bits. There are many cases which can cause an > overflow, including large FAT32 partitions and partitions that start at > a sufficiently large offset on the storage device. For large FAT32 partitions only changing of fatlength, rootdir_sect and data_begin is needed to avoid overflows. Changing of fat_sect shouldn't be needed. What do you mean exactly by "partitions starting at a sufficiently large offset on the storage device"? How do you create such partition? I've tested with a 210 GB FAT32 partition as the fourth primary partition on a 2 TB disk. This partition is the last partition on the disk, so its offset is sufficiently large. For this test only fatlength, rootdir_sect and data_begin was changed to __u32 and int and I do not see issues when listing or loading the files from this partition. > Numerous issues were observed and fixed when a 64GB FAT32 filesystem was > accessed due to truncation. > > Signed-off-by: Aaron Williams > --- > include/fat.h | 10 +++++----- > 1 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/include/fat.h b/include/fat.h > index 4c92442..7215628 100644 > --- a/include/fat.h > +++ b/include/fat.h > @@ -178,12 +178,12 @@ typedef struct dir_slot { > typedef struct { > __u8 *fatbuf; /* Current FAT buffer */ > int fatsize; /* Size of FAT in bits */ > - __u16 fatlength; /* Length of FAT in sectors */ > - __u16 fat_sect; /* Starting sector of the FAT */ > - __u16 rootdir_sect; /* Start sector of root directory */ > - __u16 sect_size; /* Size of sectors in bytes */ > + __u32 fat_sect; /* Starting sector of the FAT */ > + __u32 rootdir_sect; /* Start sector of root directory */ > + __u32 fatlength; /* Length of FAT in sectors */ > __u16 clust_size; /* Size of clusters in sectors */ > - short data_begin; /* The sector of the first cluster, can be negative */ > + __u16 sect_size; /* Size of sectors in bytes */ > + int data_begin; /* The sector of the first cluster, can be negative */ > int fatbufnum; /* Used by get_fatent, init to -1 */ > } fsdata; The patch is probably corrupted by your mailer, it doesn't apply. Thanks, Anatolij