In the Linux kernel, the following vulnerability has been resolved: erofs: preserve LZMA decoders on resize failure The pool-resize path frees each stream's old decoder before allocating its replacement

Overview

In the Linux kernel, the following vulnerability has been resolved:

erofs: preserve LZMA decoders on resize failure

The pool-resize path frees each stream's old decoder before allocating its replacement. If an allocation fails after some streams have already been replaced, the failed stream is put back on the list with state == NULL. z_erofs_lzma_max_dictsize is still advanced as if the whole pool had been resized.

An existing LZMA mount can select the broken stream and pass NULL to xz_dec_microlzma_reset(). A retry at the same size also skip another resize attempt. Since the global maximum was advanced, thus, the invalid state is left unrepaired.

Allocate each replacement before freeing the old decoder, temporarily retaining one old decoder during allocation. Stop at the first failure and advance z_erofs_lzma_max_dictsize only after all streams satisfy the request.

Record each stream's dictionary capacity so retries can skip streams already enlarged before a partial failure.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.