[PATCH stable 4.14.y 0/3] ext4: Avoid crash when journal inode extents are corrupted

[PATCH stable 4.14.y 0/3] ext4: Avoid crash when journal inode extents are corrupted

[Jan Kara]

Hello,

this is a backport of ext4 patches to avoid crashes when ext4 journal inode
extents are corrupted to 4.14.y kernel.

								Honza

[PATCH stable 4.14.y 1/3] ext4: handle error of ext4_setup_system_zone() on remount

[Jan Kara]

commit d176b1f62f242ab259ff665a26fbac69db1aecba upstream.

ext4_setup_system_zone() can fail. Handle the failure in ext4_remount().

Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200728130437.7804-2-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/super.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index eaa8bcd59b6a..8e6178dc0e6e 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5364,7 +5364,10 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
 		ext4_register_li_request(sb, first_not_zeroed);
 	}
 
-	ext4_setup_system_zone(sb);
+	err = ext4_setup_system_zone(sb);
+	if (err)
+		goto restore_opts;
+
 	if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY))
 		ext4_commit_super(sb, 1);
 
-- 
2.26.2

[PATCH stable 4.14.y 2/3] ext4: don't allow overlapping system zones

[Jan Kara]

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>
---
 fs/ext4/block_validity.c | 34 ++++++++++++----------------------
 1 file changed, 12 insertions(+), 22 deletions(-)

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index 3cbee832e796..dc2e3504bb06 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -58,7 +58,7 @@ 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;
 
@@ -69,30 +69,20 @@ 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);
-- 
2.26.2

[PATCH stable 4.14.y 3/3] ext4: check journal inode extents more carefully

[Jan Kara]

commit ce9f24cccdc019229b70a5c15e2b09ad9c0ab5d1 upstream.

Currently, system zones just track ranges of block, that are "important"
fs metadata (bitmaps, group descriptors, journal blocks, etc.). This
however complicates how extent tree (or indirect blocks) can be checked
for inodes that actually track such metadata - currently the journal
inode but arguably we should be treating quota files or resize inode
similarly. We cannot run __ext4_ext_check() on such metadata inodes when
loading their extents as that would immediately trigger the validity
checks and so we just hack around that and special-case the journal
inode. This however leads to a situation that a journal inode which has
extent tree of depth at least one can have invalid extent tree that gets
unnoticed until ext4_cache_extents() crashes.

To overcome this limitation, track inode number each system zone belongs
to (0 is used for zones not belonging to any inode). We can then verify
inode number matches the expected one when verifying extent tree and
thus avoid the false errors. With this there's no need to to
special-case journal inode during extent tree checking anymore so remove
it.

Fixes: 0a944e8a6c66 ("ext4: don't perform block validity checks on the journal inode")
Reported-by: Wolfgang Frisch <wolfgang.frisch@suse.com>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200728130437.7804-4-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---
 fs/ext4/block_validity.c | 37 +++++++++++++++++++++----------------
 fs/ext4/ext4.h           |  6 +++---
 fs/ext4/extents.c        | 16 ++++++----------
 fs/ext4/indirect.c       |  6 ++----
 fs/ext4/inode.c          |  5 ++---
 fs/ext4/mballoc.c        |  4 ++--
 6 files changed, 36 insertions(+), 38 deletions(-)

diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c
index dc2e3504bb06..080410433110 100644
--- a/fs/ext4/block_validity.c
+++ b/fs/ext4/block_validity.c
@@ -24,6 +24,7 @@ struct ext4_system_zone {
 	struct rb_node	node;
 	ext4_fsblk_t	start_blk;
 	unsigned int	count;
+	u32		ino;
 };
 
 static struct kmem_cache *ext4_system_zone_cachep;
@@ -44,7 +45,8 @@ void ext4_exit_system_zone(void)
 static inline int can_merge(struct ext4_system_zone *entry1,
 		     struct ext4_system_zone *entry2)
 {
-	if ((entry1->start_blk + entry1->count) == entry2->start_blk)
+	if ((entry1->start_blk + entry1->count) == entry2->start_blk &&
+	    entry1->ino == entry2->ino)
 		return 1;
 	return 0;
 }
@@ -56,7 +58,7 @@ static inline int can_merge(struct ext4_system_zone *entry1,
  */
 static int add_system_zone(struct ext4_sb_info *sbi,
 			   ext4_fsblk_t start_blk,
-			   unsigned int count)
+			   unsigned int count, u32 ino)
 {
 	struct ext4_system_zone *new_entry, *entry;
 	struct rb_node **n = &sbi->system_blks.rb_node, *node;
@@ -79,6 +81,7 @@ static int add_system_zone(struct ext4_sb_info *sbi,
 		return -ENOMEM;
 	new_entry->start_blk = start_blk;
 	new_entry->count = count;
+	new_entry->ino = ino;
 	new_node = &new_entry->node;
 
 	rb_link_node(new_node, parent, n);
@@ -154,16 +157,16 @@ static int ext4_protect_reserved_inode(struct super_block *sb, u32 ino)
 		if (n == 0) {
 			i++;
 		} else {
-			if (!ext4_data_block_valid(sbi, map.m_pblk, n)) {
-				ext4_error(sb, "blocks %llu-%llu from inode %u "
+			err = add_system_zone(sbi, map.m_pblk, n, ino);
+			if (err < 0) {
+				if (err == -EFSCORRUPTED) {
+					ext4_error(sb,
+					   "blocks %llu-%llu from inode %u "
 					   "overlap system zone", map.m_pblk,
 					   map.m_pblk + map.m_len - 1, ino);
-				err = -EFSCORRUPTED;
+				}
 				break;
 			}
-			err = add_system_zone(sbi, map.m_pblk, n);
-			if (err < 0)
-				break;
 			i += n;
 		}
 	}
@@ -192,16 +195,16 @@ int ext4_setup_system_zone(struct super_block *sb)
 		if (ext4_bg_has_super(sb, i) &&
 		    ((i < 5) || ((i % flex_size) == 0)))
 			add_system_zone(sbi, ext4_group_first_block_no(sb, i),
-					ext4_bg_num_gdb(sb, i) + 1);
+					ext4_bg_num_gdb(sb, i) + 1, 0);
 		gdp = ext4_get_group_desc(sb, i, NULL);
-		ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1);
+		ret = add_system_zone(sbi, ext4_block_bitmap(sb, gdp), 1, 0);
 		if (ret)
 			return ret;
-		ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1);
+		ret = add_system_zone(sbi, ext4_inode_bitmap(sb, gdp), 1, 0);
 		if (ret)
 			return ret;
 		ret = add_system_zone(sbi, ext4_inode_table(sb, gdp),
-				sbi->s_itb_per_group);
+				sbi->s_itb_per_group, 0);
 		if (ret)
 			return ret;
 	}
@@ -234,10 +237,11 @@ void ext4_release_system_zone(struct super_block *sb)
  * start_blk+count) is valid; 0 if some part of the block region
  * overlaps with filesystem metadata blocks.
  */
-int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
-			  unsigned int count)
+int ext4_inode_block_valid(struct inode *inode, ext4_fsblk_t start_blk,
+			   unsigned int count)
 {
 	struct ext4_system_zone *entry;
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 	struct rb_node *n = sbi->system_blks.rb_node;
 
 	if ((start_blk <= le32_to_cpu(sbi->s_es->s_first_data_block)) ||
@@ -253,6 +257,8 @@ int ext4_data_block_valid(struct ext4_sb_info *sbi, ext4_fsblk_t start_blk,
 		else if (start_blk >= (entry->start_blk + entry->count))
 			n = n->rb_right;
 		else {
+			if (entry->ino == inode->i_ino)
+				return 1;
 			sbi->s_es->s_last_error_block = cpu_to_le64(start_blk);
 			return 0;
 		}
@@ -275,8 +281,7 @@ int ext4_check_blockref(const char *function, unsigned int line,
 	while (bref < p+max) {
 		blk = le32_to_cpu(*bref++);
 		if (blk &&
-		    unlikely(!ext4_data_block_valid(EXT4_SB(inode->i_sb),
-						    blk, 1))) {
+		    unlikely(!ext4_inode_block_valid(inode, blk, 1))) {
 			es->s_last_error_block = cpu_to_le64(blk);
 			ext4_error_inode(inode, function, line, blk,
 					 "invalid block");
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index c5908f5eb075..5e9ff118977e 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3151,9 +3151,9 @@ extern void ext4_release_system_zone(struct super_block *sb);
 extern int ext4_setup_system_zone(struct super_block *sb);
 extern int __init ext4_init_system_zone(void);
 extern void ext4_exit_system_zone(void);
-extern int ext4_data_block_valid(struct ext4_sb_info *sbi,
-				 ext4_fsblk_t start_blk,
-				 unsigned int count);
+extern int ext4_inode_block_valid(struct inode *inode,
+				  ext4_fsblk_t start_blk,
+				  unsigned int count);
 extern int ext4_check_blockref(const char *, unsigned int,
 			       struct inode *, __le32 *, unsigned int);
 
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index fc6bc261f7ac..264332fb0e77 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -389,7 +389,7 @@ static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
 	 */
 	if (lblock + len <= lblock)
 		return 0;
-	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, len);
+	return ext4_inode_block_valid(inode, block, len);
 }
 
 static int ext4_valid_extent_idx(struct inode *inode,
@@ -397,7 +397,7 @@ static int ext4_valid_extent_idx(struct inode *inode,
 {
 	ext4_fsblk_t block = ext4_idx_pblock(ext_idx);
 
-	return ext4_data_block_valid(EXT4_SB(inode->i_sb), block, 1);
+	return ext4_inode_block_valid(inode, block, 1);
 }
 
 static int ext4_valid_extent_entries(struct inode *inode,
@@ -554,14 +554,10 @@ __read_extent_tree_block(const char *function, unsigned int line,
 	}
 	if (buffer_verified(bh) && !(flags & EXT4_EX_FORCE_CACHE))
 		return bh;
-	if (!ext4_has_feature_journal(inode->i_sb) ||
-	    (inode->i_ino !=
-	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum))) {
-		err = __ext4_ext_check(function, line, inode,
-				       ext_block_hdr(bh), depth, pblk);
-		if (err)
-			goto errout;
-	}
+	err = __ext4_ext_check(function, line, inode,
+			       ext_block_hdr(bh), depth, pblk);
+	if (err)
+		goto errout;
 	set_buffer_verified(bh);
 	/*
 	 * If this is a leaf block, cache all of its entries
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index e1801b288847..a5442528a60d 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -842,8 +842,7 @@ static int ext4_clear_blocks(handle_t *handle, struct inode *inode,
 	else if (ext4_should_journal_data(inode))
 		flags |= EXT4_FREE_BLOCKS_FORGET;
 
-	if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), block_to_free,
-				   count)) {
+	if (!ext4_inode_block_valid(inode, block_to_free, count)) {
 		EXT4_ERROR_INODE(inode, "attempt to clear invalid "
 				 "blocks %llu len %lu",
 				 (unsigned long long) block_to_free, count);
@@ -1005,8 +1004,7 @@ static void ext4_free_branches(handle_t *handle, struct inode *inode,
 			if (!nr)
 				continue;		/* A hole */
 
-			if (!ext4_data_block_valid(EXT4_SB(inode->i_sb),
-						   nr, 1)) {
+			if (!ext4_inode_block_valid(inode, nr, 1)) {
 				EXT4_ERROR_INODE(inode,
 						 "invalid indirect mapped "
 						 "block %lu (level %d)",
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index eb635eab304e..f631abb507c3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -420,8 +420,7 @@ static int __check_block_validity(struct inode *inode, const char *func,
 	    (inode->i_ino ==
 	     le32_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_journal_inum)))
 		return 0;
-	if (!ext4_data_block_valid(EXT4_SB(inode->i_sb), map->m_pblk,
-				   map->m_len)) {
+	if (!ext4_inode_block_valid(inode, map->m_pblk, map->m_len)) {
 		ext4_error_inode(inode, func, line, map->m_pblk,
 				 "lblock %lu mapped to illegal pblock %llu "
 				 "(length %d)", (unsigned long) map->m_lblk,
@@ -4940,7 +4939,7 @@ struct inode *__ext4_iget(struct super_block *sb, unsigned long ino,
 
 	ret = 0;
 	if (ei->i_file_acl &&
-	    !ext4_data_block_valid(EXT4_SB(sb), ei->i_file_acl, 1)) {
+	    !ext4_inode_block_valid(inode, ei->i_file_acl, 1)) {
 		ext4_error_inode(inode, function, line, 0,
 				 "iget: bad extended attribute block %llu",
 				 ei->i_file_acl);
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 4cafe41ab524..b4da63f24093 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3017,7 +3017,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 	block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
 
 	len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
-	if (!ext4_data_block_valid(sbi, block, len)) {
+	if (!ext4_inode_block_valid(ac->ac_inode, block, len)) {
 		ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
 			   "fs metadata", block, block+len);
 		/* File system mounted not to panic on error
@@ -4783,7 +4783,7 @@ void ext4_free_blocks(handle_t *handle, struct inode *inode,
 
 	sbi = EXT4_SB(sb);
 	if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
-	    !ext4_data_block_valid(sbi, block, count)) {
+	    !ext4_inode_block_valid(inode, block, count)) {
 		ext4_error(sb, "Freeing blocks not in datazone - "
 			   "block = %llu, count = %lu", block, count);
 		goto error_return;
-- 
2.26.2

Re: [PATCH stable 4.14.y 0/3] ext4: Avoid crash when journal inode extents are corrupted

[Jan Kara]

On Wed 17-03-21 17:44:11, Jan Kara wrote:
> Hello,
> 
> this is a backport of ext4 patches to avoid crashes when ext4 journal inode
> extents are corrupted to 4.14.y kernel.

BTW, these patches apply just fine to 4.9.y and 4.4.y stable kernels as well.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH stable 4.14.y 0/3] ext4: Avoid crash when journal inode extents are corrupted

[Greg Kroah-Hartman]

On Wed, Mar 17, 2021 at 05:55:33PM +0100, Jan Kara wrote:
> On Wed 17-03-21 17:44:11, Jan Kara wrote:
> > Hello,
> > 
> > this is a backport of ext4 patches to avoid crashes when ext4 journal inode
> > extents are corrupted to 4.14.y kernel.
> 
> BTW, these patches apply just fine to 4.9.y and 4.4.y stable kernels as well.

Many thanks for these backports, all now queued up to all 3 branches.

greg k-h