In the Linux kernel, the following vulnerability has been resolved:
io_uring: prevent reg-wait speculations
With *ENTER_EXT_ARG_REG instead of passing a user pointer with arguments for the waiting loop the user can specify an offset into a pre-mapped region of memory, in which case the [offset, offset + sizeof(io_uring_reg_wait)) will be intepreted as the argument.
As we address a kernel array using a user given index, it'd be a subject to speculation type of exploits. Use array_index_nospec() to prevent that. Make sure to pass not the full region size but truncate by the maximum offset allowed considering the structure size.
CVSS Details
- CVSS 3.1 Base Score: 5.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
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