From: Iwona Winiarska iwona.winiarska@intel.com
stable inclusion from linux-4.19.207 commit 9c8891b638319ddba9cfa330247922cd960c95b0 CVE: CVE-2021-42252
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commit b49a0e69a7b1a68c8d3f64097d06dabb770fec96 upstream.
The check mixes pages (vm_pgoff) with bytes (vm_start, vm_end) on one side of the comparison, and uses resource address (rather than just the resource size) on the other side of the comparison. This can allow malicious userspace to easily bypass the boundary check and map pages that are located outside memory-region reserved by the driver.
Fixes: 6c4e97678501 ("drivers/misc: Add Aspeed LPC control driver") Cc: stable@vger.kernel.org Signed-off-by: Iwona Winiarska iwona.winiarska@intel.com Reviewed-by: Andrew Jeffery andrew@aj.id.au Tested-by: Andrew Jeffery andrew@aj.id.au Reviewed-by: Joel Stanley joel@aj.id.au Signed-off-by: Joel Stanley joel@jms.id.au Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com Reviewed-by: Xiu Jianfeng xiujianfeng@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/misc/aspeed-lpc-ctrl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/misc/aspeed-lpc-ctrl.c b/drivers/misc/aspeed-lpc-ctrl.c index a024f8042259a..870ab0dfcde06 100644 --- a/drivers/misc/aspeed-lpc-ctrl.c +++ b/drivers/misc/aspeed-lpc-ctrl.c @@ -50,7 +50,7 @@ static int aspeed_lpc_ctrl_mmap(struct file *file, struct vm_area_struct *vma) unsigned long vsize = vma->vm_end - vma->vm_start; pgprot_t prot = vma->vm_page_prot;
- if (vma->vm_pgoff + vsize > lpc_ctrl->mem_base + lpc_ctrl->mem_size) + if (vma->vm_pgoff + vma_pages(vma) > lpc_ctrl->mem_size >> PAGE_SHIFT) return -EINVAL;
/* ast2400/2500 AHB accesses are not cache coherent */