Vulnerability CVE-2024-46794
Published: 2024-09-18

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

x86/tdx: Fix data leak in mmio_read()

The mmio_read() function makes a TDVMCALL to retrieve MMIO data for an
address from the VMM.

Sean noticed that mmio_read() unintentionally exposes the value of an
initialized variable (val) on the stack to the VMM.

This variable is only needed as an output value. It did not need to be
passed to the VMM in the first place.

Do not send the original value of *val to the VMM.

[ dhansen: clarify what 'val' is used for. ]

 References:
https://git.kernel.org/stable/c/26c6af49d26ffc377e392e30d4086db19eed0ef7
https://git.kernel.org/stable/c/ef00818c50cf55a3a56bd9a9fae867c92dfb84e7
https://git.kernel.org/stable/c/b55ce742afcb8e8189d82f2f1e635ba1b5a461fa
https://git.kernel.org/stable/c/b6fb565a2d15277896583d471b21bc14a0c99661
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