In the Linux kernel, the following vulnerability has been resolved:
ext4: fix kernel BUG in ext4_write_inline_data_end
When the data=journal mount option is used, the ext4_journalled_write_end() function incorrectly calls ext4_write_inline_data_end() without checking if the EXT4_STATE_MAY_INLINE_DATA flag is still set on the inode.
If a previous attempt to convert the inline data to an extent failed (e.g. due to ENOSPC), the EXT4_STATE_MAY_INLINE_DATA flag is cleared, but the EXT4_INODE_INLINE_DATA flag remains set. In this scenario, the next call to ext4_write_begin() will not prepare the inline data xattr for writing, but ext4_journalled_write_end() will incorrectly attempt to write to it, triggering a BUG_ON(pos + len > EXT4_I(inode)->i_inline_size) in ext4_write_inline_data() since i_inline_size was not expanded.
Fix this by ensuring that ext4_journalled_write_end() only calls ext4_write_inline_data_end() if the EXT4_STATE_MAY_INLINE_DATA flag is set, mirroring the behavior of ext4_write_end() and ext4_da_write_end().
References
- https://git.kernel.org/stable/c/0ae42b51607240990614e0843f0d3529aaff62cc
- https://git.kernel.org/stable/c/260830a9a706f5d335398236fc788ce32f220de1
- https://git.kernel.org/stable/c/9808ae9fae996afa942bd963a39c9b1cdeebd0bd
- https://git.kernel.org/stable/c/ad09aa45965d3fafaf9963bc78109b73c0f9ac8d
- https://git.kernel.org/stable/c/f00f5c0dd55319bc33b76f72c853bda0e0a32eda