diff options
| author | Julius Werner <jwerner@chromium.org> | 2017-06-02 15:36:39 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-06-14 13:16:26 +0200 |
| commit | 983c09ebdbc2c047b608021411d70d5c4404b1a6 (patch) | |
| tree | 9a7fb07831a01db6d8288804c740c7bc2c672c9b | |
| parent | 9a9388953bdcd416f94991f3bd19ea9bc2b31930 (diff) | |
drivers: char: mem: Fix wraparound check to allow mappings up to the end
commit 32829da54d9368103a2f03269a5120aa9ee4d5da upstream.
A recent fix to /dev/mem prevents mappings from wrapping around the end
of physical address space. However, the check was written in a way that
also prevents a mapping reaching just up to the end of physical address
space, which may be a valid use case (especially on 32-bit systems).
This patch fixes it by checking the last mapped address (instead of the
first address behind that) for overflow.
Fixes: b299cde245 ("drivers: char: mem: Check for address space wraparound with mmap()")
Reported-by: Nico Huber <nico.h@gmx.de>
Signed-off-by: Julius Werner <jwerner@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/mem.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 0975d23031ea..2898d19fadf5 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -346,7 +346,7 @@ static int mmap_mem(struct file *file, struct vm_area_struct *vma) phys_addr_t offset = (phys_addr_t)vma->vm_pgoff << PAGE_SHIFT; /* It's illegal to wrap around the end of the physical address space. */ - if (offset + (phys_addr_t)size < offset) + if (offset + (phys_addr_t)size - 1 < offset) return -EINVAL; if (!valid_mmap_phys_addr_range(vma->vm_pgoff, size)) |