CVE ID:	CVE-2023-52733
Description:	In the Linux kernel, the following vulnerability has been resolved: s390/decompressor: specify __decompress() buf len to avoid overflow Historically calls to __decompress() didn't specify "out_len" parameter on many architectures including s390, expecting that no writes beyond uncompressed kernel image are performed. This has changed since commit 2aa14b1ab2c4 ("zstd: import usptream v1.5.2") which includes zstd library commit 6a7ede3dfccb ("Reduce size of dctx by reutilizing dst buffer (#2751)"). Now zstd decompression code might store literal buffer in the unwritten portion of the destination buffer. Since "out_len" is not set, it is considered to be unlimited and hence free to use for optimization needs. On s390 this might corrupt initrd or ipl report which are often placed right after the decompressor buffer. Luckily the size of uncompressed kernel image is already known to the decompressor, so to avoid the problem simply specify it in the "out_len" parameter.
Test IDs:	None available
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2023-52733 https://git.kernel.org/stable/c/16409f7d9ca5bb8220e1049ea9aae0d3c94d2dfb https://git.kernel.org/stable/c/16409f7d9ca5bb8220e1049ea9aae0d3c94d2dfb https://git.kernel.org/stable/c/55dbd6f4ea954751340f4f73d5dcd7c8f12208b2 https://git.kernel.org/stable/c/55dbd6f4ea954751340f4f73d5dcd7c8f12208b2 https://git.kernel.org/stable/c/7ab41c2c08a32132ba8c14624910e2fe8ce4ba4b https://git.kernel.org/stable/c/7ab41c2c08a32132ba8c14624910e2fe8ce4ba4b https://git.kernel.org/stable/c/9ed522143f959630f8b7782ddc212900d8f609a9 https://git.kernel.org/stable/c/9ed522143f959630f8b7782ddc212900d8f609a9 https://git.kernel.org/stable/c/f1eb22d0ff064ad458b3b1a1eaa84ac3996206c2 https://git.kernel.org/stable/c/f1eb22d0ff064ad458b3b1a1eaa84ac3996206c2