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authorIan Abbott <abbotti@mev.co.uk>2009-02-24 12:22:59 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2009-03-24 19:38:25 -0400
commit6da2d377bba06c29d0bc41c8dee014164dec82a7 (patch)
tree46bdf19836227b27c4548431ec7cea5eeb2a8a08 /drivers/uio
parent1bafeb378e915f39b1bf44ee0871823d6f402ea5 (diff)
UIO: Take offset into account when determining number of pages that can be mapped
If a UIO memory region does not start on a page boundary but straddles one, the number of actual pages that overlap the memory region may be calculated incorrectly because the offset isn't taken into account. If userspace sets the mmap length to offset+size, it may fail with -EINVAL if UIO thinks it's trying to allocate too many pages. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Cc: Hans J. Koch <hjk@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/uio')
-rw-r--r--drivers/uio/uio.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 68a496557788..03efb065455f 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -708,7 +708,8 @@ static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
708 return -EINVAL; 708 return -EINVAL;
709 709
710 requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; 710 requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
711 actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT; 711 actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
712 + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
712 if (requested_pages > actual_pages) 713 if (requested_pages > actual_pages)
713 return -EINVAL; 714 return -EINVAL;
714 715