From 868c9ddc182bc6728bb380cbfb3170734f72c599 Mon Sep 17 00:00:00 2001 From: Dominique Martinet Date: Wed, 7 Jul 2021 14:12:54 +0900 Subject: [PATCH] swiotlb: add overflow checks to swiotlb_bounce This is a follow-up on 5f89468e2f06 ("swiotlb: manipulate orig_addr when tlb_addr has offset") which fixed unaligned dma mappings, making sure the following overflows are caught: - offset of the start of the slot within the device bigger than requested address' offset, in other words if the base address given in swiotlb_tbl_map_single to create the mapping (orig_addr) was after the requested address for the sync (tlb_offset) in the same block: |------------------------------------------| block <----------------------------> mapped part of the block ^ orig_addr ^ invalid tlb_addr for sync - if the resulting offset was bigger than the allocation size this one could happen if the mapping was not until the end. e.g. |------------------------------------------| block <---------------------> mapped part of the block ^ ^ orig_addr invalid tlb_addr Both should never happen so print a warning and bail out without trying to adjust the sizes/offsets: the first one could try to sync from orig_addr to whatever is left of the requested size, but the later really has nothing to sync there... Signed-off-by: Dominique Martinet Cc: Konrad Rzeszutek Wilk Reviewed-by: Bumyong Lee Cc: Christoph Hellwig Signed-off-by: Konrad Rzeszutek Wilk --- kernel/dma/swiotlb.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index b7f76bca89bf..f1a9ae7fad8f 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -365,13 +365,27 @@ static void swiotlb_bounce(struct device *dev, phys_addr_t tlb_addr, size_t size size_t alloc_size = mem->slots[index].alloc_size; unsigned long pfn = PFN_DOWN(orig_addr); unsigned char *vaddr = phys_to_virt(tlb_addr); - unsigned int tlb_offset; + unsigned int tlb_offset, orig_addr_offset; if (orig_addr == INVALID_PHYS_ADDR) return; - tlb_offset = (tlb_addr & (IO_TLB_SIZE - 1)) - - swiotlb_align_offset(dev, orig_addr); + tlb_offset = tlb_addr & (IO_TLB_SIZE - 1); + orig_addr_offset = swiotlb_align_offset(dev, orig_addr); + if (tlb_offset < orig_addr_offset) { + dev_WARN_ONCE(dev, 1, + "Access before mapping start detected. orig offset %u, requested offset %u.\n", + orig_addr_offset, tlb_offset); + return; + } + + tlb_offset -= orig_addr_offset; + if (tlb_offset > alloc_size) { + dev_WARN_ONCE(dev, 1, + "Buffer overflow detected. Allocation size: %zu. Mapping size: %zu+%u.\n", + alloc_size, size, tlb_offset); + return; + } orig_addr += tlb_offset; alloc_size -= tlb_offset;