Messages in this thread | | | From | OGAWA Hirofumi <> | Subject | Re: [PATCH] fat: Relax checks for sector size and media type | Date | Mon, 03 Sep 2018 16:17:26 +0900 |
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Pali Rohár <pali.rohar@gmail.com> writes:
> Windows fastfat.sys driver accepts also media types 0x00 and 0x01 and > sector sizes 128 and 256 bytes. Linux mkfs.fat can format disk also to > larger FAT sector sizes then 4096 bytes, therefore relax also upper limit > restriction.
> - if (!is_power_of_2(bpb->fat_sector_size) > - || (bpb->fat_sector_size < 512) > - || (bpb->fat_sector_size > 4096)) { > + if (!is_power_of_2(bpb->fat_sector_size)) {
Just relaxing validation doesn't work. The block layer doesn't support smaller than 512, and lager than PAGE_SIZE. (And in specification, fat doesn't support lager than 4096.)
> static inline int fat_valid_media(u8 media) > { > - return 0xf8 <= media || media == 0xf0; > + return 0xf8 <= media || media == 0xf0 || media == 0x00 || media == 0x01; > } > #endif /* !_LINUX_MSDOS_FS_H */
This is ok though, this would be for ancient floppy media.
Thanks. -- OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
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