From: Mingming Cao Date: Sun, 25 Jun 2006 12:47:50 +0000 (-0700) Subject: [PATCH] Avoid disk sector_t overflow for >2TB ext3 filesystem X-Git-Tag: v2.6.18-rc1~988 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fcd5df35882b128ef3e160fab3074e6fe7ae501b;p=linux-2.6 [PATCH] Avoid disk sector_t overflow for >2TB ext3 filesystem If ext3 filesystem 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. Verified this patch on a 32 bit platform without CONFIG_LBD defined (sector_t is 32 bits long), mount refuse to mount a 10TB ext3. Signed-off-by: Mingming Cao Acked-by: Andreas Dilger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/ext3/resize.c b/fs/ext3/resize.c index 34b39e9a1e..a31dff81ed 100644 --- a/fs/ext3/resize.c +++ b/fs/ext3/resize.c @@ -925,6 +925,16 @@ int ext3_group_extend(struct super_block *sb, struct ext3_super_block *es, 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 --git a/fs/ext3/super.c b/fs/ext3/super.c index a60cc6ec13..df98a77092 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -1565,6 +1565,16 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) 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; + } + if (EXT3_BLOCKS_PER_GROUP(sb) == 0) goto cantfind_ext3; sbi->s_groups_count = (le32_to_cpu(es->s_blocks_count) -