s390: fix initrd corruption in decompressor with new zstd version

[PATCH 0/1] s390: fix initrd corruption in decompressor with new zstd version

Vasily Gorbik posted 1 patch 2 years, 7 months ago

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arch/s390/boot/decompressor.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

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[PATCH 0/1] s390: fix initrd corruption in decompressor with new zstd version

Posted by Vasily Gorbik 2 years, 7 months ago

The new version of zstd library integrated in the kernel since v6.2-rc1
https://lore.kernel.org/all/20221024202606.404049-1-nickrterrell@gmail.com/
contains commit
https://github.com/facebook/zstd/commit/6a7ede3dfccb
which introduces a side effect for historical usage of __decompress() function,
i.e. not specifying "out_len" parameter and expecting that no writes beyond
uncompressed kernel image are performed. More details are in follow up fix.

From architectures which claim HAVE_KERNEL_ZSTD, s390 and MIPS use
__decompress() without specifying "out_len". On s390 this leads to
initrd corruption.
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2003348

I haven't looked in details for MIPS but I've added Thomas as the
maintainer and MIPS list in Cc.

The follow up fix addresses that for s390.

Vasily Gorbik (1):
  s390/decompressor: specify __decompress() buf len to avoid overflow

 arch/s390/boot/decompressor.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

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2.38.1