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authorRyan Roberts <ryan.roberts@arm.com>2023-06-02 12:29:46 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-06-10 02:25:55 +0300
commitb3f78e74986546a6da5d28c24e627d95d17f79ec (patch)
tree7ec12d72f26a0d6492db565b2997f8aa0dc28da9 /mm/vmalloc.c
parent501b26510ae3bbdf9333b83addcd4e5c4214346d (diff)
downloadlinux-b3f78e74986546a6da5d28c24e627d95d17f79ec.tar.xz
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 <ryan.roberts@arm.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: Lorenzo Stoakes <lstoakes@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: SeongJae Park <sj@kernel.org> Cc: Yu Zhao <yuzhao@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/vmalloc.c')
-rw-r--r--mm/vmalloc.c10
1 files changed, 8 insertions, 2 deletions
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;
}