[PATCH mm v3 26/38] kasan, vmalloc: don't unpoison VM_ALLOC pages before mapping
From: <hidden>
Date: 2021-12-13 21:54:52
Also in:
linux-mm, lkml
Subsystem:
memory management, the rest, vmalloc · Maintainers:
Andrew Morton, Linus Torvalds, Uladzislau Rezki
From: Andrey Konovalov <redacted> Make KASAN unpoison vmalloc mappings after that have been mapped in when it's possible: for vmalloc() (indentified via VM_ALLOC) and vm_map_ram(). The reasons for this are: - For vmalloc() and vm_map_ram(): pages don't get unpoisoned in case mapping them fails. - For vmalloc(): HW_TAGS KASAN needs pages to be mapped to set tags via kasan_unpoison_vmalloc(). Signed-off-by: Andrey Konovalov <redacted> --- Changes v2->v3: - Update patch description. --- mm/vmalloc.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 58bd2f7f86d7..9a6862e274df 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c@@ -2208,14 +2208,15 @@ void *vm_map_ram(struct page **pages, unsigned int count, int node) mem = (void *)addr; } - mem = kasan_unpoison_vmalloc(mem, size); - if (vmap_pages_range(addr, addr + size, PAGE_KERNEL, pages, PAGE_SHIFT) < 0) { vm_unmap_ram(mem, count); return NULL; } + /* Mark the pages as accessible after they were mapped in. */ + mem = kasan_unpoison_vmalloc(mem, size); + return mem; } EXPORT_SYMBOL(vm_map_ram);
@@ -2443,7 +2444,14 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, setup_vmalloc_vm(area, va, flags, caller); - area->addr = kasan_unpoison_vmalloc(area->addr, requested_size); + /* + * For VM_ALLOC mappings, __vmalloc_node_range() mark the pages as + * accessible after they are mapped in. + * Otherwise, as the pages can be mapped outside of vmalloc code, + * mark them now as a best-effort approach. + */ + if (!(flags & VM_ALLOC)) + area->addr = kasan_unpoison_vmalloc(area->addr, requested_size); return area; }
@@ -3104,6 +3112,12 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, if (!addr) goto fail; + /* + * Mark the pages for VM_ALLOC mappings as accessible after they were + * mapped in. + */ + addr = kasan_unpoison_vmalloc(addr, real_size); + /* * In this function, newly allocated vm_struct has VM_UNINITIALIZED * flag. It means that vm_struct is not fully initialized.
@@ -3799,7 +3813,11 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets, } spin_unlock(&vmap_area_lock); - /* mark allocated areas as accessible */ + /* + * Mark allocated areas as accessible. + * As the pages are mapped outside of vmalloc code, + * mark them now as a best-effort approach. + */ for (area = 0; area < nr_vms; area++) vms[area]->addr = kasan_unpoison_vmalloc(vms[area]->addr, vms[area]->size);
--
2.25.1
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