概要

In the Linux kernel, the following vulnerability has been resolved:binder: fix async_free_space accounting for empty parcelsIn 4.13, commit 74310e06be4d ( android: binder: Move buffer out of area shared with user space )fixed a kernel structure visibility issue. As part of that patch,sizeof(void *) was used as the buffer size for 0-length data payloads sothe driver could detect abusive clients sending 0-length asynchronoustransactions to a server by enforcing limits on async_free_size.Unfortunately, on the free side, the accounting of async_free_spacedid not add the sizeof(void *) back. The result was that up to 8-bytes ofasync_free_space were leaked on every async transaction of 8-bytes orless. These small transactions are uncommon, so this accounting issuehas gone undetected for several years.The fix is to use buffer_size (the allocated buffer size) instead of size (the logical buffer size) when updating the async_free_spaceduring the free operation. These are the same except for thiscorner case of asynchronous transactions with payloads < 8 bytes.

CVSS v3 指标

安全公告

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