Gitweb: http://git.kernel.org/linus/6da2d377bba06c29d0bc41c8dee014164dec82a7
Commit: 6da2d377bba06c29d0bc41c8dee014164dec82a7
Parent: 1bafeb378e915f39b1bf44ee0871823d6f402ea5
Author: Ian Abbott <abbotti@mev.co.uk>
AuthorDate: Tue Feb 24 17:22:59 2009 +0000
Committer: Greg Kroah-Hartman <gregkh@suse.de>
CommitDate: Tue Mar 24 16:38:25 2009 -0700
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>
---
drivers/uio/uio.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 68a4965..03efb06 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)
return -EINVAL;
requested_pages = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
- actual_pages = (idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
+ actual_pages = ((idev->info->mem[mi].addr & ~PAGE_MASK)
+ + idev->info->mem[mi].size + PAGE_SIZE -1) >> PAGE_SHIFT;
if (requested_pages > actual_pages)
return -EINVAL;
--
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