[RFC 2/13] extents and 48bit ext3: sector_t overflow check
Mingming Cao <[email protected]>
| Newsgroups | gmane.comp.file-systems.ext2.devel,gmane.linux.kernel,gmane.linux.file-systems |
|---|---|
| Organization | IBM LTC |
| Message-ID | <[email protected]> |
If ext3 fs system is larger than 2TB, and sector_t is a u32 (i.e. CONFIG_LBD not defined in the kernel), the calculation of the disk sector will overflow. Add check at ext3_fill_super() and ext3_group_extend() to prevent mount/remount/resize >2TB ext3 filesystem if sector_t size is 4 bytes. Signed-Off-By: Mingming Cao<[email protected]> Acked-by: Andreas Dilger <[email protected]> --- linux-2.6.16-ming/fs/ext3/resize.c | 10 ++++++++++ linux-2.6.16-ming/fs/ext3/super.c | 10 ++++++++++ 2 files changed, 20 insertions(+) diff -puN fs/ext3/resize.c~ext3_check_sector_t_overflow fs/ext3/resize.c --- linux-2.6.16/fs/ext3/resize.c~ext3_check_sector_t_overflow 2006-06-07 15:42:26.000000000 -0700 +++ linux-2.6.16-ming/fs/ext3/resize.c 2006-06-08 16:50:07.390825336 -0700 @@ -925,6 +925,16 @@ int ext3_group_extend(struct super_block if (n_blocks_count == 0 || n_blocks_count == o_blocks_count) return 0; + if (n_blocks_count > (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { + printk(KERN_ERR "EXT3-fs: filesystem on %s" + " too large to resize to %lu blocks safely\n", + sb->s_id, n_blocks_count); + if (sizeof(sector_t) < 8) + ext3_warning(sb, __FUNCTION__, + "CONFIG_LBD not enabled\n"); + return -EINVAL; + } + if (n_blocks_count < o_blocks_count) { ext3_warning(sb, __FUNCTION__, "can't shrink FS - resize aborted"); diff -puN fs/ext3/super.c~ext3_check_sector_t_overflow fs/ext3/super.c --- linux-2.6.16/fs/ext3/super.c~ext3_check_sector_t_overflow 2006-06-07 15:42:26.000000000 -0700 +++ linux-2.6.16-ming/fs/ext3/super.c 2006-06-08 16:50:07.394824881 -0700 @@ -1579,6 +1579,16 @@ static int ext3_fill_super (struct super goto failed_mount; } + if (le32_to_cpu(es->s_blocks_count) > + (sector_t)(~0ULL) >> (sb->s_blocksize_bits - 9)) { + printk(KERN_ERR "EXT3-fs: filesystem on %s" + " too large to mount safely\n", sb->s_id); + if (sizeof(sector_t) < 8) + printk(KERN_WARNING + "EXT3-fs: CONFIG_LBD not enabled\n"); + goto failed_mount; + } + bgl_lock_init(&sbi->s_blockgroup_lock); for (i = 0; i < db_count; i++) { _