From 66578b0b2f69659f00b6169e6fe7377c4b100d18 Mon Sep 17 00:00:00 2001 From: Yann Droneaud Date: Mon, 13 Apr 2015 14:56:23 +0200 Subject: [PATCH] IB/core: don't disallow registering region starting at 0x0 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: # 8494057ab5e4 ("IB/uverbs: Prevent integer overflow in ib_umem_get address arithmetic") Cc: Shachar Raindel Cc: Jack Morgenstein Cc: Or Gerlitz Signed-off-by: Yann Droneaud Reviewed-by: Sagi Grimberg Reviewed-by: Haggai Eran Signed-off-by: Doug Ledford --- 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 9ac4068d2088..38acb3cfc545 100644 --- a/drivers/infiniband/core/umem.c +++ b/drivers/infiniband/core/umem.c @@ -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()) -- 2.20.1