From b3f78e74986546a6da5d28c24e627d95d17f79ec Mon Sep 17 00:00:00 2001 From: Ryan Roberts Date: Fri, 2 Jun 2023 10:29:46 +0100 Subject: mm: vmalloc must set pte via arch code Patch series "Fixes for pte encapsulation bypasses", v3. A series to improve the encapsulation of pte entries by disallowing non-arch code from directly dereferencing pte_t pointers. This patch (of 4): It is bad practice to directly set pte entries within a pte table. Instead all modifications must go through arch-provided helpers such as set_pte_at() to give the arch code visibility and allow it to check (and potentially modify) the operation. Link: https://lkml.kernel.org/r/20230602092949.545577-1-ryan.roberts@arm.com Link: https://lkml.kernel.org/r/20230602092949.545577-2-ryan.roberts@arm.com Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function") Signed-off-by: Ryan Roberts Reviewed-by: Zi Yan Acked-by: Lorenzo Stoakes Reviewed-by: Christoph Hellwig Reviewed-by: Uladzislau Rezki (Sony) Reviewed-by: Mike Rapoport (IBM) Cc: Kirill A. Shutemov Cc: Matthew Wilcox (Oracle) Cc: SeongJae Park Cc: Yu Zhao Signed-off-by: Andrew Morton --- mm/vmalloc.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'mm/vmalloc.c') diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 7c32435219b1..9d64a4098c36 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2944,10 +2944,16 @@ struct vmap_pfn_data { static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private) { struct vmap_pfn_data *data = private; + unsigned long pfn = data->pfns[data->idx]; + pte_t ptent; - if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx]))) + if (WARN_ON_ONCE(pfn_valid(pfn))) return -EINVAL; - *pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot)); + + ptent = pte_mkspecial(pfn_pte(pfn, data->prot)); + set_pte_at(&init_mm, addr, pte, ptent); + + data->idx++; return 0; } -- cgit v1.2.3