swiotlb: fix out-of-bounds TLB allocations with CONFIG_SWIOTLB_DYNAMIC

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: swiotlb: fix out-of-bounds TLB allocations with CONFIG_SWIOTLB_DYNAMIC Limit the free list length to the size of the IO TLB. Transient pool can be smaller than IO_TLB_SEGSIZE, but the free list is initialized with the assumption that the total number of slots is a multiple of IO_TLB_SEGSIZE. As a result, swiotlb_area_find_slots() may allocate slots past the end of a transient IO TLB buffer.

References

• https://git.kernel.org/stable/c/ce7612496a4ba6068bc68aa1fa9d947dadb4ad9b
• https://git.kernel.org/stable/c/53c87e846e335e3c18044c397cc35178163d7827