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IB/core: don't disallow registering region starting at 0x0

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In a call to ib_umem_get(), if address is 0x0 and size is
already page aligned, check added in commit 8494057ab5
("IB/uverbs: Prevent integer overflow in ib_umem_get address
arithmetic") will refuse to register a memory region that
could otherwise be valid (provided vm.mmap_min_addr sysctl
and mmap_low_allowed SELinux knobs allow userspace to map
something at address 0x0).

This patch allows back such registration: ib_umem_get()
should probably don't care of the base address provided it
can be pinned with get_user_pages().

There's two possible overflows, in (addr + size) and in
PAGE_ALIGN(addr + size), this patch keep ensuring none
of them happen while allowing to pin memory at address
0x0. Anyway, the case of size equal 0 is no more (partially)
handled as 0-length memory region are disallowed by an
earlier check.

Link: http://mid.gmane.org/[email protected]
Cc: <[email protected]> # 8494057ab5 ("IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic")
Cc: Shachar Raindel <[email protected]>
Cc: Jack Morgenstein <[email protected]>
Cc: Or Gerlitz <[email protected]>
Signed-off-by: Yann Droneaud <[email protected]>
Reviewed-by: Sagi Grimberg <[email protected]>
Reviewed-by: Haggai Eran <[email protected]>
Signed-off-by: Doug Ledford <[email protected]>
This commit is contained in:
Yann Droneaud 2015-04-13 14:56:23 +02:00 • committed by Doug Ledford
commit 66578b0b2f
1 changed files with 2 additions and 2 deletions
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4
drivers/infiniband/core/umem.c
View file

@ -106,8 +106,8 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
* If the combination of the addr and size requested for this memory
* region causes an integer overflow, return error.
*/
if ((PAGE_ALIGN(addr + size) <= size) ||
(PAGE_ALIGN(addr + size) <= addr))
if (((addr + size) < addr) ||
PAGE_ALIGN(addr + size) < (addr + size))
return ERR_PTR(-EINVAL);
if (!can_do_mlock())