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 <jonathan.salwan@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index b27c96d..6ed4df2 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -79,12 +79,20 @@
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 @@
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)",