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authorJan Kara <jack@suse.cz>2021-03-17 17:44:13 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2021-03-24 10:59:21 +0100
commitf175d63724fa0738c060a1e07f796f353e4e729f (patch)
treeadb8d2d2d1280ff01526ad1b0bdbafb464c451f2 /fs
parentd01b5fc061683e8fc28499b283fab39838730c9b (diff)
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ext4: don't allow overlapping system zones
commit bf9a379d0980e7413d94cb18dac73db2bfc5f470 upstream. Currently, add_system_zone() just silently merges two added system zones that overlap. However the overlap should not happen and it generally suggests that some unrelated metadata overlap which indicates the fs is corrupted. We should have caught such problems earlier (e.g. in ext4_check_descriptors()) but add this check as another line of defense. In later patch we also use this for stricter checking of journal inode extent tree. Reviewed-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20200728130437.7804-3-jack@suse.cz Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/block_validity.c34
1 files changed, 12 insertions, 22 deletions
diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index 45c7b0f9a8e3..bc15226518ff 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -57,7 +57,7 @@ static int add_system_zone(struct ext4_sb_info *sbi,
ext4_fsblk_t start_blk,
unsigned int count)
{
- struct ext4_system_zone *new_entry = NULL, *entry;
+ struct ext4_system_zone *new_entry, *entry;
struct rb_node **n = &sbi->system_blks.rb_node, *node;
struct rb_node *parent = NULL, *new_node = NULL;
@@ -68,30 +68,20 @@ static int add_system_zone(struct ext4_sb_info *sbi,
n = &(*n)->rb_left;
else if (start_blk >= (entry->start_blk + entry->count))
n = &(*n)->rb_right;
- else {
- if (start_blk + count > (entry->start_blk +
- entry->count))
- entry->count = (start_blk + count -
- entry->start_blk);
- new_node = *n;
- new_entry = rb_entry(new_node, struct ext4_system_zone,
- node);
- break;
- }
+ else /* Unexpected overlap of system zones. */
+ return -EFSCORRUPTED;
}
- if (!new_entry) {
- new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
- GFP_KERNEL);
- if (!new_entry)
- return -ENOMEM;
- new_entry->start_blk = start_blk;
- new_entry->count = count;
- new_node = &new_entry->node;
+ new_entry = kmem_cache_alloc(ext4_system_zone_cachep,
+ GFP_KERNEL);
+ if (!new_entry)
+ return -ENOMEM;
+ new_entry->start_blk = start_blk;
+ new_entry->count = count;
+ new_node = &new_entry->node;
- rb_link_node(new_node, parent, n);
- rb_insert_color(new_node, &sbi->system_blks);
- }
+ rb_link_node(new_node, parent, n);
+ rb_insert_color(new_node, &sbi->system_blks);
/* Can we merge to the left? */
node = rb_prev(new_node);