Commit 53c87e84 authored by Petr Tesarik's avatar Petr Tesarik Committed by Christoph Hellwig
Browse files

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: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
Closes: https://lore.kernel.org/linux-iommu/104a8c8fedffd1ff8a2890983e2ec1c26bff6810.camel@linux.ibm.com/


Fixes: 79636caa ("swiotlb: if swiotlb is full, fall back to a transient memory pool")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPetr Tesarik <petr.tesarik1@huawei-partners.com>
Reviewed-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent a409d960

kernel/dma/swiotlb.c

+2 −1
Original line number Diff line number Diff line
@@ -283,7 +283,8 @@ static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t start, 
	}



	for (i = 0; i < mem->nslabs; i++) {

		mem->slots[i].list = IO_TLB_SEGSIZE - io_tlb_offset(i);

		mem->slots[i].list = min(IO_TLB_SEGSIZE - io_tlb_offset(i),

					 mem->nslabs - i);

		mem->slots[i].orig_addr = INVALID_PHYS_ADDR;

		mem->slots[i].alloc_size = 0;

	}