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 <andreyknvl@google.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Eric Auger <eric.auger@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Jens Wiklander <jens.wiklander@linaro.org> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -157,6 +157,7 @@ static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
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static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
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struct videobuf_buffer *vb)
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{
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unsigned long untagged_baddr = untagged_addr(vb->baddr);
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long prev_pfn, this_pfn;
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@ -164,22 +165,22 @@ static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
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unsigned int offset;
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int ret;
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offset = vb->baddr & ~PAGE_MASK;
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offset = untagged_baddr & ~PAGE_MASK;
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mem->size = PAGE_ALIGN(vb->size + offset);
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ret = -EINVAL;
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down_read(&mm->mmap_sem);
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vma = find_vma(mm, vb->baddr);
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vma = find_vma(mm, untagged_baddr);
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if (!vma)
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goto out_up;
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if ((vb->baddr + mem->size) > vma->vm_end)
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if ((untagged_baddr + mem->size) > vma->vm_end)
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goto out_up;
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pages_done = 0;
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prev_pfn = 0; /* kill warning */
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user_address = vb->baddr;
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user_address = untagged_baddr;
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while (pages_done < (mem->size >> PAGE_SHIFT)) {
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ret = follow_pfn(vma, user_address, &this_pfn);
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