Restored vmalloc regions are currently not properly marked for KASAN, causing KASAN to treat accesses to these regions as out-of-bounds. Fix this by properly unpoisoning the restored vmalloc area using kasan_unpoison_vmalloc(). This requires setting the VM_UNINITIALIZED flag during the initial area allocation and clearing it after the pages have been mapped and unpoisoned, using the clear_vm_uninitialized_flag() helper. Reported-by: Pratyush Yadav Fixes: a667300bd53f ("kho: add support for preserving vmalloc allocations") Signed-off-by: Pasha Tatashin --- kernel/liveupdate/kexec_handover.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c index 410098bae0bf..747a35107c84 100644 --- a/kernel/liveupdate/kexec_handover.c +++ b/kernel/liveupdate/kexec_handover.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -1077,6 +1078,7 @@ EXPORT_SYMBOL_GPL(kho_unpreserve_vmalloc); void *kho_restore_vmalloc(const struct kho_vmalloc *preservation) { struct kho_vmalloc_chunk *chunk = KHOSER_LOAD_PTR(preservation->first); + kasan_vmalloc_flags_t kasan_flags = KASAN_VMALLOC_PROT_NORMAL; unsigned int align, order, shift, vm_flags; unsigned long total_pages, contig_pages; unsigned long addr, size; @@ -1128,7 +1130,8 @@ void *kho_restore_vmalloc(const struct kho_vmalloc *preservation) goto err_free_pages_array; area = __get_vm_area_node(total_pages * PAGE_SIZE, align, shift, - vm_flags, VMALLOC_START, VMALLOC_END, + vm_flags | VM_UNINITIALIZED, + VMALLOC_START, VMALLOC_END, NUMA_NO_NODE, GFP_KERNEL, __builtin_return_address(0)); if (!area) @@ -1143,6 +1146,13 @@ void *kho_restore_vmalloc(const struct kho_vmalloc *preservation) area->nr_pages = total_pages; area->pages = pages; + if (vm_flags & VM_ALLOC) + kasan_flags |= KASAN_VMALLOC_VM_ALLOC; + + area->addr = kasan_unpoison_vmalloc(area->addr, total_pages * PAGE_SIZE, + kasan_flags); + clear_vm_uninitialized_flag(area); + return area->addr; err_free_vm_area: -- 2.53.0.414.gf7e9f6c205-goog