[PATCH AUTOSEL 4.4 46/77] hfsplus: fix BUG on bnode parent update

[PATCH AUTOSEL 4.4 46/77] hfsplus: fix BUG on bnode parent update

[Sasha Levin]

From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit 19a9d0f1acf75e8be8cfba19c1a34e941846fa2b ]

Creating, renaming or deleting a file may hit BUG_ON() if the first
record of both a leaf node and its parent are changed, and if this
forces the parent to be split.  This bug is triggered by xfstests
generic/027, somewhat rarely; here is a more reliable reproducer:

  truncate -s 50M fs.iso
  mkfs.hfsplus fs.iso
  mount fs.iso /mnt
  i=1000
  while [ $i -le 2400 ]; do
    touch /mnt/$i &>/dev/null
    ((++i))
  done
  i=2400
  while [ $i -ge 1000 ]; do
    mv /mnt/$i /mnt/$(perl -e "print $i x61") &>/dev/null
    ((--i))
  done

The issue is that a newly created bnode is being put twice.  Reset
new_node to NULL in hfs_brec_update_parent() before reaching goto again.

Link: http://lkml.kernel.org/r/5ee1db09b60373a15890f6a7c835d00e76bf601d.1535682461.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfsplus/brec.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/hfsplus/brec.c b/fs/hfsplus/brec.c
index 1002a0c08319b..20ce698251ad1 100644
--- a/fs/hfsplus/brec.c
+++ b/fs/hfsplus/brec.c
@@ -447,6 +447,7 @@ static int hfs_brec_update_parent(struct hfs_find_data *fd)
 			/* restore search_key */
 			hfs_bnode_read_key(node, fd->search_key, 14);
 		}
+		new_node = NULL;
 	}
 
 	if (!rec && node->parent)
-- 
2.20.1

[PATCH AUTOSEL 4.4 47/77] hfs: fix BUG on bnode parent update

[Sasha Levin]

From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit ef75bcc5763d130451a99825f247d301088b790b ]

hfs_brec_update_parent() may hit BUG_ON() if the first record of both a
leaf node and its parent are changed, and if this forces the parent to
be split.  It is not possible for this to happen on a valid hfs
filesystem because the index nodes have fixed length keys.

For reasons I ignore, the hfs module does have support for a number of
hfsplus features.  A corrupt btree header may report variable length
keys and trigger this BUG, so it's better to fix it.

Link: http://lkml.kernel.org/r/cf9b02d57f806217a2b1bf5db8c3e39730d8f603.1535682463.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/brec.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/hfs/brec.c b/fs/hfs/brec.c
index 2e713673df42f..85dab71bee74f 100644
--- a/fs/hfs/brec.c
+++ b/fs/hfs/brec.c
@@ -444,6 +444,7 @@ static int hfs_brec_update_parent(struct hfs_find_data *fd)
 			/* restore search_key */
 			hfs_bnode_read_key(node, fd->search_key, 14);
 		}
+		new_node = NULL;
 	}
 
 	if (!rec && node->parent)
-- 
2.20.1

[PATCH AUTOSEL 4.4 48/77] hfsplus: prevent btree data loss on ENOSPC

[Sasha Levin]

From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit d92915c35bfaf763d78bf1d5ac7f183420e3bd99 ]

Inserting or deleting a record in a btree may require splitting several of
its nodes.  If we hit ENOSPC halfway through, the new nodes will be left
orphaned and their records will be lost.  This could mean lost inodes,
extents or xattrs.

Henceforth, check the available disk space before making any changes.
This still leaves the potential problem of corruption on ENOMEM.

The patch can be tested with xfstests generic/027.

Link: http://lkml.kernel.org/r/4596eef22fbda137b4ffa0272d92f0da15364421.1536269129.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfsplus/attributes.c | 10 ++++++++++
 fs/hfsplus/btree.c      | 44 ++++++++++++++++++++++++++---------------
 fs/hfsplus/catalog.c    | 24 ++++++++++++++++++++++
 fs/hfsplus/extents.c    |  4 ++++
 fs/hfsplus/hfsplus_fs.h |  2 ++
 5 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/fs/hfsplus/attributes.c b/fs/hfsplus/attributes.c
index e5b221de7de63..d7455ea702878 100644
--- a/fs/hfsplus/attributes.c
+++ b/fs/hfsplus/attributes.c
@@ -216,6 +216,11 @@ int hfsplus_create_attr(struct inode *inode,
 	if (err)
 		goto failed_init_create_attr;
 
+	/* Fail early and avoid ENOSPC during the btree operation */
+	err = hfs_bmap_reserve(fd.tree, fd.tree->depth + 1);
+	if (err)
+		goto failed_create_attr;
+
 	if (name) {
 		err = hfsplus_attr_build_key(sb, fd.search_key,
 						inode->i_ino, name);
@@ -312,6 +317,11 @@ int hfsplus_delete_attr(struct inode *inode, const char *name)
 	if (err)
 		return err;
 
+	/* Fail early and avoid ENOSPC during the btree operation */
+	err = hfs_bmap_reserve(fd.tree, fd.tree->depth);
+	if (err)
+		goto out;
+
 	if (name) {
 		err = hfsplus_attr_build_key(sb, fd.search_key,
 						inode->i_ino, name);
diff --git a/fs/hfsplus/btree.c b/fs/hfsplus/btree.c
index 7adc8a327e03a..1ae3e187bc9d0 100644
--- a/fs/hfsplus/btree.c
+++ b/fs/hfsplus/btree.c
@@ -341,26 +341,21 @@ static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 	return node;
 }
 
-struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
+/* Make sure @tree has enough space for the @rsvd_nodes */
+int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
 {
-	struct hfs_bnode *node, *next_node;
-	struct page **pagep;
-	u32 nidx, idx;
-	unsigned off;
-	u16 off16;
-	u16 len;
-	u8 *data, byte, m;
-	int i;
+	struct inode *inode = tree->inode;
+	struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
+	u32 count;
+	int res;
 
-	while (!tree->free_nodes) {
-		struct inode *inode = tree->inode;
-		struct hfsplus_inode_info *hip = HFSPLUS_I(inode);
-		u32 count;
-		int res;
+	if (rsvd_nodes <= 0)
+		return 0;
 
+	while (tree->free_nodes < rsvd_nodes) {
 		res = hfsplus_file_extend(inode, hfs_bnode_need_zeroout(tree));
 		if (res)
-			return ERR_PTR(res);
+			return res;
 		hip->phys_size = inode->i_size =
 			(loff_t)hip->alloc_blocks <<
 				HFSPLUS_SB(tree->sb)->alloc_blksz_shift;
@@ -368,9 +363,26 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 			hip->alloc_blocks << HFSPLUS_SB(tree->sb)->fs_shift;
 		inode_set_bytes(inode, inode->i_size);
 		count = inode->i_size >> tree->node_size_shift;
-		tree->free_nodes = count - tree->node_count;
+		tree->free_nodes += count - tree->node_count;
 		tree->node_count = count;
 	}
+	return 0;
+}
+
+struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
+{
+	struct hfs_bnode *node, *next_node;
+	struct page **pagep;
+	u32 nidx, idx;
+	unsigned off;
+	u16 off16;
+	u16 len;
+	u8 *data, byte, m;
+	int i, res;
+
+	res = hfs_bmap_reserve(tree, 1);
+	if (res)
+		return ERR_PTR(res);
 
 	nidx = 0;
 	node = hfs_bnode_find(tree, nidx);
diff --git a/fs/hfsplus/catalog.c b/fs/hfsplus/catalog.c
index 022974ab6e3cc..e35df33583c4f 100644
--- a/fs/hfsplus/catalog.c
+++ b/fs/hfsplus/catalog.c
@@ -264,6 +264,14 @@ int hfsplus_create_cat(u32 cnid, struct inode *dir,
 	if (err)
 		return err;
 
+	/*
+	 * Fail early and avoid ENOSPC during the btree operations. We may
+	 * have to split the root node at most once.
+	 */
+	err = hfs_bmap_reserve(fd.tree, 2 * fd.tree->depth);
+	if (err)
+		goto err2;
+
 	hfsplus_cat_build_key_with_cnid(sb, fd.search_key, cnid);
 	entry_size = hfsplus_fill_cat_thread(sb, &entry,
 		S_ISDIR(inode->i_mode) ?
@@ -332,6 +340,14 @@ int hfsplus_delete_cat(u32 cnid, struct inode *dir, struct qstr *str)
 	if (err)
 		return err;
 
+	/*
+	 * Fail early and avoid ENOSPC during the btree operations. We may
+	 * have to split the root node at most once.
+	 */
+	err = hfs_bmap_reserve(fd.tree, 2 * (int)fd.tree->depth - 2);
+	if (err)
+		goto out;
+
 	if (!str) {
 		int len;
 
@@ -429,6 +445,14 @@ int hfsplus_rename_cat(u32 cnid,
 		return err;
 	dst_fd = src_fd;
 
+	/*
+	 * Fail early and avoid ENOSPC during the btree operations. We may
+	 * have to split the root node at most twice.
+	 */
+	err = hfs_bmap_reserve(src_fd.tree, 4 * (int)src_fd.tree->depth - 1);
+	if (err)
+		goto out;
+
 	/* find the old dir entry and read the data */
 	err = hfsplus_cat_build_key(sb, src_fd.search_key,
 			src_dir->i_ino, src_name);
diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index feca524ce2a5c..ce0b8f8374081 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -99,6 +99,10 @@ static int __hfsplus_ext_write_extent(struct inode *inode,
 	if (hip->extent_state & HFSPLUS_EXT_NEW) {
 		if (res != -ENOENT)
 			return res;
+		/* Fail early and avoid ENOSPC during the btree operation */
+		res = hfs_bmap_reserve(fd->tree, fd->tree->depth + 1);
+		if (res)
+			return res;
 		hfs_brec_insert(fd, hip->cached_extents,
 				sizeof(hfsplus_extent_rec));
 		hip->extent_state &= ~(HFSPLUS_EXT_DIRTY | HFSPLUS_EXT_NEW);
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index f91a1faf819e9..0ab6541493405 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -310,6 +310,7 @@ static inline unsigned short hfsplus_min_io_size(struct super_block *sb)
 #define hfs_btree_open hfsplus_btree_open
 #define hfs_btree_close hfsplus_btree_close
 #define hfs_btree_write hfsplus_btree_write
+#define hfs_bmap_reserve hfsplus_bmap_reserve
 #define hfs_bmap_alloc hfsplus_bmap_alloc
 #define hfs_bmap_free hfsplus_bmap_free
 #define hfs_bnode_read hfsplus_bnode_read
@@ -394,6 +395,7 @@ u32 hfsplus_calc_btree_clump_size(u32 block_size, u32 node_size, u64 sectors,
 struct hfs_btree *hfs_btree_open(struct super_block *sb, u32 id);
 void hfs_btree_close(struct hfs_btree *tree);
 int hfs_btree_write(struct hfs_btree *tree);
+int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes);
 struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree);
 void hfs_bmap_free(struct hfs_bnode *node);
 
-- 
2.20.1

[PATCH AUTOSEL 4.4 49/77] hfs: prevent btree data loss on ENOSPC

[Sasha Levin]

From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit 54640c7502e5ed41fbf4eedd499e85f9acc9698f ]

Inserting a new record in a btree may require splitting several of its
nodes.  If we hit ENOSPC halfway through, the new nodes will be left
orphaned and their records will be lost.  This could mean lost inodes or
extents.

Henceforth, check the available disk space before making any changes.
This still leaves the potential problem of corruption on ENOMEM.

There is no need to reserve space before deleting a catalog record, as we
do for hfsplus.  This difference is because hfs index nodes have fixed
length keys.

Link: http://lkml.kernel.org/r/ab5fc8a7d5ffccfd5f27b1cf2cb4ceb6c110da74.1536269131.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/btree.c   | 41 +++++++++++++++++++++++++----------------
 fs/hfs/btree.h   |  1 +
 fs/hfs/catalog.c | 16 ++++++++++++++++
 fs/hfs/extent.c  |  4 ++++
 4 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/fs/hfs/btree.c b/fs/hfs/btree.c
index 1ff5774a5382a..9e9b02f5134b0 100644
--- a/fs/hfs/btree.c
+++ b/fs/hfs/btree.c
@@ -219,25 +219,17 @@ static struct hfs_bnode *hfs_bmap_new_bmap(struct hfs_bnode *prev, u32 idx)
 	return node;
 }
 
-struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
+/* Make sure @tree has enough space for the @rsvd_nodes */
+int hfs_bmap_reserve(struct hfs_btree *tree, int rsvd_nodes)
 {
-	struct hfs_bnode *node, *next_node;
-	struct page **pagep;
-	u32 nidx, idx;
-	unsigned off;
-	u16 off16;
-	u16 len;
-	u8 *data, byte, m;
-	int i;
-
-	while (!tree->free_nodes) {
-		struct inode *inode = tree->inode;
-		u32 count;
-		int res;
+	struct inode *inode = tree->inode;
+	u32 count;
+	int res;
 
+	while (tree->free_nodes < rsvd_nodes) {
 		res = hfs_extend_file(inode);
 		if (res)
-			return ERR_PTR(res);
+			return res;
 		HFS_I(inode)->phys_size = inode->i_size =
 				(loff_t)HFS_I(inode)->alloc_blocks *
 				HFS_SB(tree->sb)->alloc_blksz;
@@ -245,9 +237,26 @@ struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
 					  tree->sb->s_blocksize_bits;
 		inode_set_bytes(inode, inode->i_size);
 		count = inode->i_size >> tree->node_size_shift;
-		tree->free_nodes = count - tree->node_count;
+		tree->free_nodes += count - tree->node_count;
 		tree->node_count = count;
 	}
+	return 0;
+}
+
+struct hfs_bnode *hfs_bmap_alloc(struct hfs_btree *tree)
+{
+	struct hfs_bnode *node, *next_node;
+	struct page **pagep;
+	u32 nidx, idx;
+	unsigned off;
+	u16 off16;
+	u16 len;
+	u8 *data, byte, m;
+	int i, res;
+
+	res = hfs_bmap_reserve(tree, 1);
+	if (res)
+		return ERR_PTR(res);
 
 	nidx = 0;
 	node = hfs_bnode_find(tree, nidx);
diff --git a/fs/hfs/btree.h b/fs/hfs/btree.h
index f6bd266d70b55..2715f416b5a80 100644
--- a/fs/hfs/btree.h
+++ b/fs/hfs/btree.h
@@ -81,6 +81,7 @@ struct hfs_find_data {
 extern struct hfs_btree *hfs_btree_open(struct super_block *, u32, btree_keycmp);
 extern void hfs_btree_close(struct hfs_btree *);
 extern void hfs_btree_write(struct hfs_btree *);
+extern int hfs_bmap_reserve(struct hfs_btree *, int);
 extern struct hfs_bnode * hfs_bmap_alloc(struct hfs_btree *);
 extern void hfs_bmap_free(struct hfs_bnode *node);
 
diff --git a/fs/hfs/catalog.c b/fs/hfs/catalog.c
index db458ee3a5467..34158c276200e 100644
--- a/fs/hfs/catalog.c
+++ b/fs/hfs/catalog.c
@@ -97,6 +97,14 @@ int hfs_cat_create(u32 cnid, struct inode *dir, struct qstr *str, struct inode *
 	if (err)
 		return err;
 
+	/*
+	 * Fail early and avoid ENOSPC during the btree operations. We may
+	 * have to split the root node at most once.
+	 */
+	err = hfs_bmap_reserve(fd.tree, 2 * fd.tree->depth);
+	if (err)
+		goto err2;
+
 	hfs_cat_build_key(sb, fd.search_key, cnid, NULL);
 	entry_size = hfs_cat_build_thread(sb, &entry, S_ISDIR(inode->i_mode) ?
 			HFS_CDR_THD : HFS_CDR_FTH,
@@ -294,6 +302,14 @@ int hfs_cat_move(u32 cnid, struct inode *src_dir, struct qstr *src_name,
 		return err;
 	dst_fd = src_fd;
 
+	/*
+	 * Fail early and avoid ENOSPC during the btree operations. We may
+	 * have to split the root node at most once.
+	 */
+	err = hfs_bmap_reserve(src_fd.tree, 2 * src_fd.tree->depth);
+	if (err)
+		goto out;
+
 	/* find the old dir entry and read the data */
 	hfs_cat_build_key(sb, src_fd.search_key, src_dir->i_ino, src_name);
 	err = hfs_brec_find(&src_fd);
diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index e33a0d36a93eb..1bd1afefe2538 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -117,6 +117,10 @@ static int __hfs_ext_write_extent(struct inode *inode, struct hfs_find_data *fd)
 	if (HFS_I(inode)->flags & HFS_FLG_EXT_NEW) {
 		if (res != -ENOENT)
 			return res;
+		/* Fail early and avoid ENOSPC during the btree operation */
+		res = hfs_bmap_reserve(fd->tree, fd->tree->depth + 1);
+		if (res)
+			return res;
 		hfs_brec_insert(fd, HFS_I(inode)->cached_extents, sizeof(hfs_extent_rec));
 		HFS_I(inode)->flags &= ~(HFS_FLG_EXT_DIRTY|HFS_FLG_EXT_NEW);
 	} else {
-- 
2.20.1

[PATCH AUTOSEL 4.4 50/77] hfsplus: fix return value of hfsplus_get_block()

[Sasha Levin]

From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit 839c3a6a5e1fbc8542d581911b35b2cb5cd29304 ]

Direct writes to empty inodes fail with EIO.  The generic direct-io code
is in part to blame (a patch has been submitted as "direct-io: allow
direct writes to empty inodes"), but hfsplus is worse affected than the
other filesystems because the fallback to buffered I/O doesn't happen.

The problem is the return value of hfsplus_get_block() when called with
!create.  Change it to be more consistent with the other modules.

Link: http://lkml.kernel.org/r/2cd1301404ec7cf1e39c8f11a01a4302f1460ad6.1539195310.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfsplus/extents.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c
index ce0b8f8374081..d93c051559cb8 100644
--- a/fs/hfsplus/extents.c
+++ b/fs/hfsplus/extents.c
@@ -236,7 +236,9 @@ int hfsplus_get_block(struct inode *inode, sector_t iblock,
 	ablock = iblock >> sbi->fs_shift;
 
 	if (iblock >= hip->fs_blocks) {
-		if (iblock > hip->fs_blocks || !create)
+		if (!create)
+			return 0;
+		if (iblock > hip->fs_blocks)
 			return -EIO;
 		if (ablock >= hip->alloc_blocks) {
 			res = hfsplus_file_extend(inode, false);
-- 
2.20.1

[PATCH AUTOSEL 4.4 51/77] hfs: fix return value of hfs_get_block()

[Sasha Levin]

From: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>

[ Upstream commit 1267a07be5ebbff2d2739290f3d043ae137c15b4 ]

Direct writes to empty inodes fail with EIO.  The generic direct-io code
is in part to blame (a patch has been submitted as "direct-io: allow
direct writes to empty inodes"), but hfs is worse affected than the other
filesystems because the fallback to buffered I/O doesn't happen.

The problem is the return value of hfs_get_block() when called with
!create.  Change it to be more consistent with the other modules.

Link: http://lkml.kernel.org/r/4538ab8c35ea37338490525f0f24cbc37227528c.1539195310.git.ernesto.mnd.fernandez@gmail.com
Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Reviewed-by: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/extent.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index 1bd1afefe2538..16819d2a978b4 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -345,7 +345,9 @@ int hfs_get_block(struct inode *inode, sector_t block,
 	ablock = (u32)block / HFS_SB(sb)->fs_div;
 
 	if (block >= HFS_I(inode)->fs_blocks) {
-		if (block > HFS_I(inode)->fs_blocks || !create)
+		if (!create)
+			return 0;
+		if (block > HFS_I(inode)->fs_blocks)
 			return -EIO;
 		if (ablock >= HFS_I(inode)->alloc_blocks) {
 			res = hfs_extend_file(inode);
-- 
2.20.1

[PATCH AUTOSEL 4.4 52/77] fs/hfs/extent.c: fix array out of bounds read of array extent

[Sasha Levin]

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit 6c9a3f843a29d6894dfc40df338b91dbd78f0ae3 ]

Currently extent and index i are both being incremented causing an array
out of bounds read on extent[i].  Fix this by removing the extraneous
increment of extent.

Ernesto said:

: This is only triggered when deleting a file with a resource fork.  I
: may be wrong because the documentation isn't clear, but I don't think
: you can create those under linux.  So I guess nobody was testing them.
:
: > A disk space leak, perhaps?
:
: That's what it looks like in general.  hfs_free_extents() won't do
: anything if the block count doesn't add up, and the error will be
: ignored.  Now, if the block count randomly does add up, we could see
: some corruption.

Detected by CoverityScan, CID#711541 ("Out of bounds read")

Link: http://lkml.kernel.org/r/20180831140538.31566-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Ernesto A. Fernndez <ernesto.mnd.fernandez@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/hfs/extent.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/hfs/extent.c b/fs/hfs/extent.c
index 16819d2a978b4..cbe4fca96378a 100644
--- a/fs/hfs/extent.c
+++ b/fs/hfs/extent.c
@@ -304,7 +304,7 @@ int hfs_free_fork(struct super_block *sb, struct hfs_cat_file *file, int type)
 		return 0;
 
 	blocks = 0;
-	for (i = 0; i < 3; extent++, i++)
+	for (i = 0; i < 3; i++)
 		blocks += be16_to_cpu(extent[i].count);
 
 	res = hfs_free_extents(sb, extent, blocks, blocks);
-- 
2.20.1