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Commit b302ef2d authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: verify group number in verify_group_input() before using it 



Check the group number for sanity earilier, before calling routines
such as ext4_bg_has_super() or ext4_group_overhead_blocks().

Reported-by: default avatarJonathan Salwan <jonathan.salwan@gmail.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent a1d8d9a7

fs/ext4/resize.c

+11 −6
Original line number Diff line number Diff line
@@ -79,12 +79,20 @@ static int verify_group_input(struct super_block *sb, 
	ext4_fsblk_t end = start + input->blocks_count;

	ext4_group_t group = input->group;

	ext4_fsblk_t itend = input->inode_table + sbi->s_itb_per_group;

	unsigned overhead = ext4_group_overhead_blocks(sb, group);

	ext4_fsblk_t metaend = start + overhead;

	unsigned overhead;

	ext4_fsblk_t metaend;

	struct buffer_head *bh = NULL;

	ext4_grpblk_t free_blocks_count, offset;

	int err = -EINVAL;



	if (group != sbi->s_groups_count) {

		ext4_warning(sb, "Cannot add at group %u (only %u groups)",

			     input->group, sbi->s_groups_count);

		return -EINVAL;

	}



	overhead = ext4_group_overhead_blocks(sb, group);

	metaend = start + overhead;

	input->free_blocks_count = free_blocks_count =

		input->blocks_count - 2 - overhead - sbi->s_itb_per_group;
@@ -96,10 +104,7 @@ static int verify_group_input(struct super_block *sb, 
		       free_blocks_count, input->reserved_blocks);



	ext4_get_group_no_and_offset(sb, start, NULL, &offset);

	if (group != sbi->s_groups_count)

		ext4_warning(sb, "Cannot add at group %u (only %u groups)",

			     input->group, sbi->s_groups_count);

	else if (offset != 0)

	if (offset != 0)

			ext4_warning(sb, "Last group not full");

	else if (input->reserved_blocks > input->blocks_count / 5)

		ext4_warning(sb, "Reserved blocks too high (%u)",