| From | lizf@kernel ... | Subject | [PATCH 3.4 169/172] IB/core: don't disallow registering region starting at 0x0 | Date | Tue, 16 Jun 2015 16:37:03 +0800 |
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From: Yann Droneaud <ydroneaud@opteya.com>
3.4.108-rc1 review patch. If anyone has any objections, please let me know.
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commit 66578b0b2f69659f00b6169e6fe7377c4b100d18 upstream.
In a call to ib_umem_get(), if address is 0x0 and size is already page aligned, check added in commit 8494057ab5e4 ("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/cover.1428929103.git.ydroneaud@opteya.com Cc: Shachar Raindel <raindel@mellanox.com> Cc: Jack Morgenstein <jackm@mellanox.com> Cc: Or Gerlitz <ogerlitz@mellanox.com> Signed-off-by: Yann Droneaud <ydroneaud@opteya.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: Haggai Eran <haggaie@mellanox.com> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Zefan Li <lizefan@huawei.com> --- drivers/infiniband/core/umem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/infiniband/core/umem.c b/drivers/infiniband/core/umem.c index 055ebeb..d0254be 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -98,8 +98,8 @@ 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()) -- 1.9.1
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