If ib_umem_get() is called with a size equal to 0 and an
non-page aligned address, one page will be pinned and a
0-sized umem will be returned to the caller.
This should not be allowed: it's not expected for a memory
region to have a size equal to 0.
This patch adds a check to explicitly refuse to register
a 0-sized region.
Additionally, it updates check added in commit 8494057ab5e4
("IB/uverbs: Prevent integer overflow in ib_umem_get
address arithmetic") to not care about 0-sized region:
it would had catched 0-sized region only if address was
already page aligned.
Link: http://mid.gmane.org/cover.1428502843.git.ydroneaud@xxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx # 8494057ab5e4 ("IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic")
Cc: Shachar Raindel <raindel@xxxxxxxxxxxx>
Cc: Jack Morgenstein <jackm@xxxxxxxxxxxx>
Cc: Or Gerlitz <ogerlitz@xxxxxxxxxxxx>
Signed-off-by: Yann Droneaud <ydroneaud@xxxxxxxxxx>
---
drivers/infiniband/core/umem.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c
index 8c014b5dab4c..cbe361645c1b 100644
--- a/drivers/infiniband/core/umem.c
+++ b/drivers/infiniband/core/umem.c
@@ -99,12 +99,15 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
if (dmasync)
dma_set_attr(DMA_ATTR_WRITE_BARRIER, &attrs);
+ if (!size)
+ return ERR_PTR(-EINVAL);
+
/*
* 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))
+ (PAGE_ALIGN(addr + size) < addr))
return ERR_PTR(-EINVAL);
if (!can_do_mlock())
--
2.1.0
--
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