Fix these two error paths:

1. When set_memory_decrypted() fails, pages may be left fully or partially decrypted.

2. Decrypted pages may be freed if swiotlb_alloc_tlb() determines that the physical address is too high.

To fix the first issue, call set_memory_encrypted() on the allocated region after a failed decryption attempt. If that also fails, leak the pages.

To fix the second issue, check that the TLB physical address is below the requested limit before decrypting.

Let the caller differentiate between unsuitable physical address (=> retry from a lower zone) and allocation failures (=> no point in retrying).

Cc: stable@vger.kernel.org Cc: Rick Edgecombe rick.p.edgecombe@intel.com Fixes: 79636caad361 ("swiotlb: if swiotlb is full, fall back to a transient memory pool") Signed-off-by: Petr Tesarik petr.tesarik1@huawei-partners.com --- kernel/dma/swiotlb.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index dff067bd56b1..0e1632f75421 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -558,29 +558,40 @@ void __init swiotlb_exit(void) * alloc_dma_pages() - allocate pages to be used for DMA * @gfp: GFP flags for the allocation. * @bytes: Size of the buffer. + * @phys_limit: Maximum allowed physical address of the buffer. * * Allocate pages from the buddy allocator. If successful, make the allocated * pages decrypted that they can be used for DMA. * - * Return: Decrypted pages, or %NULL on failure. + * Return: Decrypted pages, %NULL on allocation failure, or ERR_PTR(-EAGAIN) + * if the allocated physical address was above @phys_limit. */ -static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes) +static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, u64 phys_limit) { unsigned int order = get_order(bytes); struct page *page; + phys_addr_t paddr; void *vaddr;

page = alloc_pages(gfp, order); if (!page) return NULL;

- vaddr = page_address(page); + paddr = page_to_phys(page); + if (paddr + bytes - 1 > phys_limit) { + __free_pages(page, order); + return ERR_PTR(-EAGAIN); + } + + vaddr = phys_to_virt(paddr); if (set_memory_decrypted((unsigned long)vaddr, PFN_UP(bytes))) goto error; return page;

error: - __free_pages(page, order); + /* Intentional leak if pages cannot be encrypted again. */ + if (!set_memory_encrypted((unsigned long)vaddr, PFN_UP(bytes))) + __free_pages(page, order); return NULL; }

@@ -618,11 +629,7 @@ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes, else if (phys_limit <= DMA_BIT_MASK(32)) gfp |= __GFP_DMA32;

- while ((page = alloc_dma_pages(gfp, bytes)) && - page_to_phys(page) + bytes - 1 > phys_limit) { - /* allocated, but too high */ - __free_pages(page, get_order(bytes)); - + while (IS_ERR(page = alloc_dma_pages(gfp, bytes, phys_limit))) { if (IS_ENABLED(CONFIG_ZONE_DMA32) && phys_limit < DMA_BIT_MASK(64) && !(gfp & (__GFP_DMA32 | __GFP_DMA)))