From 111a87bbfd89bf6360c0d6b776c20171a11da7b1 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 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 Cc: Jack Morgenstein Cc: Or Gerlitz Signed-off-by: Yann Droneaud Reviewed-by: Sagi Grimberg Reviewed-by: Haggai Eran Signed-off-by: Doug Ledford Signed-off-by: Ben Hutchings --- Reading git-format-patch failed