From eb13a42605ab8560b02fdeb117f119f327e4776d Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 17 Jun 2018 18:11:20 -0400 Subject: [PATCH] ext4: add more mount time checks of the superblock commit bfe0a5f47ada40d7984de67e59a7d3390b9b9ecc upstream. The kernel's ext4 mount-time checks were more permissive than e2fsprogs's libext2fs checks when opening a file system. The superblock is considered too insane for debugfs or e2fsck to operate on it, the kernel has no business trying to mount it. This will make file system fuzzing tools work harder, but the failure cases that they find will be more useful and be easier to evaluate. Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/super.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 25e078e..fff215a1 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -3656,6 +3656,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) le32_to_cpu(es->s_log_block_size)); goto failed_mount; } + if (le32_to_cpu(es->s_log_cluster_size) > + (EXT4_MAX_CLUSTER_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) { + ext4_msg(sb, KERN_ERR, + "Invalid log cluster size: %u", + le32_to_cpu(es->s_log_cluster_size)); + goto failed_mount; + } if (le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks) > (blocksize / 4)) { ext4_msg(sb, KERN_ERR, @@ -3794,13 +3801,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) "block size (%d)", clustersize, blocksize); goto failed_mount; } - if (le32_to_cpu(es->s_log_cluster_size) > - (EXT4_MAX_CLUSTER_LOG_SIZE - EXT4_MIN_BLOCK_LOG_SIZE)) { - ext4_msg(sb, KERN_ERR, - "Invalid log cluster size: %u", - le32_to_cpu(es->s_log_cluster_size)); - goto failed_mount; - } sbi->s_cluster_bits = le32_to_cpu(es->s_log_cluster_size) - le32_to_cpu(es->s_log_block_size); sbi->s_clusters_per_group = @@ -3821,10 +3821,10 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) } } else { if (clustersize != blocksize) { - ext4_warning(sb, "fragment/cluster size (%d) != " - "block size (%d)", clustersize, - blocksize); - clustersize = blocksize; + ext4_msg(sb, KERN_ERR, + "fragment/cluster size (%d) != " + "block size (%d)", clustersize, blocksize); + goto failed_mount; } if (sbi->s_blocks_per_group > blocksize * 8) { ext4_msg(sb, KERN_ERR, @@ -3878,6 +3878,13 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) ext4_blocks_count(es)); goto failed_mount; } + if ((es->s_first_data_block == 0) && (es->s_log_block_size == 0) && + (sbi->s_cluster_ratio == 1)) { + ext4_msg(sb, KERN_WARNING, "bad geometry: first data " + "block is 0 with a 1k block and cluster size"); + goto failed_mount; + } + blocks_count = (ext4_blocks_count(es) - le32_to_cpu(es->s_first_data_block) + EXT4_BLOCKS_PER_GROUP(sb) - 1); @@ -3913,6 +3920,14 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) ret = -ENOMEM; goto failed_mount; } + if (((u64)sbi->s_groups_count * sbi->s_inodes_per_group) != + le32_to_cpu(es->s_inodes_count)) { + ext4_msg(sb, KERN_ERR, "inodes count not valid: %u vs %llu", + le32_to_cpu(es->s_inodes_count), + ((u64)sbi->s_groups_count * sbi->s_inodes_per_group)); + ret = -EINVAL; + goto failed_mount; + } bgl_lock_init(sbi->s_blockgroup_lock); -- 2.7.4