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.

Reported-by: Niklas Schnelle <[email protected]>
Closes: https://lore.kernel.org/linux-iommu/[email protected]/
Fixes: 79636caad361 ("swiotlb: if swiotlb is full, fall back to a transient memory pool")
Cc: [email protected]
Signed-off-by: Petr Tesarik <[email protected]>
Reviewed-by: Halil Pasic <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

0 files changed, 0 insertions, 0 deletions