From b302ef2d3c73d8a07ed2f0679ce35f00b6dcacef Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Thu, 6 Jun 2013 11:14:31 -0400 Subject: [PATCH] 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: Jonathan Salwan Signed-off-by: "Theodore Ts'o" --- fs/ext4/resize.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index b27c96d01965..6ed4df27da8d 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -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)",