From e275faf367e3a3b9db06a71924b199f429d3d508 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Wed, 25 Sep 2019 16:48:54 -0700 Subject: media/v4l2-core: untag user pointers in videobuf_dma_contig_user_get This patch is a part of a series that extends kernel ABI to allow to pass tagged user pointers (with the top byte set to something else other than 0x00) as syscall arguments. videobuf_dma_contig_user_get() uses provided user pointers for vma lookups, which can only by done with untagged pointers. Untag the pointers in this function. Link: http://lkml.kernel.org/r/100436d5f8e4349a78f27b0bbb27e4801fcb946b.1563904656.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Khalid Aziz Reviewed-by: Kees Cook Acked-by: Mauro Carvalho Chehab Cc: Al Viro Cc: Catalin Marinas Cc: Dave Hansen Cc: Eric Auger Cc: Felix Kuehling Cc: Jens Wiklander Cc: Mike Rapoport Cc: Vincenzo Frascino Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/media/v4l2-core/videobuf-dma-contig.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'drivers') diff --git a/drivers/media/v4l2-core/videobuf-dma-contig.c b/drivers/media/v4l2-core/videobuf-dma-contig.c index 76b4ac7b1678..aeb2f497c683 100644 --- a/drivers/media/v4l2-core/videobuf-dma-contig.c +++ b/drivers/media/v4l2-core/videobuf-dma-contig.c @@ -157,6 +157,7 @@ static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem) static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem, struct videobuf_buffer *vb) { + unsigned long untagged_baddr = untagged_addr(vb->baddr); struct mm_struct *mm = current->mm; struct vm_area_struct *vma; unsigned long prev_pfn, this_pfn; @@ -164,22 +165,22 @@ static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem, unsigned int offset; int ret; - offset = vb->baddr & ~PAGE_MASK; + offset = untagged_baddr & ~PAGE_MASK; mem->size = PAGE_ALIGN(vb->size + offset); ret = -EINVAL; down_read(&mm->mmap_sem); - vma = find_vma(mm, vb->baddr); + vma = find_vma(mm, untagged_baddr); if (!vma) goto out_up; - if ((vb->baddr + mem->size) > vma->vm_end) + if ((untagged_baddr + mem->size) > vma->vm_end) goto out_up; pages_done = 0; prev_pfn = 0; /* kill warning */ - user_address = vb->baddr; + user_address = untagged_baddr; while (pages_done < (mem->size >> PAGE_SHIFT)) { ret = follow_pfn(vma, user_address, &this_pfn); -- cgit v1.2.3