[PATCH 3.16 080/366] ext4: bubble errors from ext4_find_inline_data_nolock() up to ext4_iget()

Ben Hutchings
2018-11-12T05:56:23Z

From: Theodore Ts'o <tytso@mit.edu>

commit eb9b5f01c33adebc31cbc236c02695f605b0e417 upstream.

If ext4_find_inline_data_nolock() returns an error it needs to get
reflected up to ext4_iget(). In order to fix this,
ext4_iget_extra_inode() needs to return an error (and not return
void).

This is related to "ext4: do not allow external inodes for inline
data" (which fixes CVE-2018-11412) in that in the errors=continue
case, it would be useful to for userspace to receive an error
indicating that file system is corrupted.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/ext4/inode.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4159,19 +4159,21 @@ static blkcnt_t ext4_inode_blocks(struct
}
}

-static inline void ext4_iget_extra_inode(struct inode *inode,
+static inline int ext4_iget_extra_inode(struct inode *inode,
struct ext4_inode *raw_inode,
struct ext4_inode_info *ei)
{
__le32 *magic = (void *)raw_inode +
EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize;
+
if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize + sizeof(__le32) <=
EXT4_INODE_SIZE(inode->i_sb) &&
*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) {
ext4_set_inode_state(inode, EXT4_STATE_XATTR);
- ext4_find_inline_data_nolock(inode);
+ return ext4_find_inline_data_nolock(inode);
} else
EXT4_I(inode)->i_inline_off = 0;
+ return 0;
}

struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
@@ -4331,7 +4333,9 @@ struct inode *ext4_iget(struct super_blo
ei->i_extra_isize = sizeof(struct ext4_inode) -
EXT4_GOOD_OLD_INODE_SIZE;
} else {
- ext4_iget_extra_inode(inode, raw_inode, ei);
+ ret = ext4_iget_extra_inode(inode, raw_inode, ei);
+ if (ret)
+ goto bad_inode;
}
}