The list of pages in a vmalloc chunk is NULL-terminated. So when looping through the pages in a vmalloc chunk, both kho_restore_vmalloc() and kho_vmalloc_unpreserve_chunk() rightly make sure to stop when encountering a NULL page. But when the chunk is full, the loops do not stop and go past the bounds of chunk->phys, resulting in out-of-bounds memory access, and possibly the restoration or unpreservation of an invalid page. Fix this by making sure the processing of chunk stops at the end of the array. Fixes: a667300bd53f2 ("kho: add support for preserving vmalloc allocations") Signed-off-by: Pratyush Yadav --- Notes: Commit 89a3ecca49ee8 ("kho: make sure page being restored is actually from KHO") was quite helpful in catching this since kho_restore_page() errored out due to missing magic number, instead of "restoring" a random page and causing errors at other random places. kernel/kexec_handover.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c index 76f0940fb4856..cc5aaa738bc50 100644 --- a/kernel/kexec_handover.c +++ b/kernel/kexec_handover.c @@ -869,7 +869,7 @@ static void kho_vmalloc_unpreserve_chunk(struct kho_vmalloc_chunk *chunk) __kho_unpreserve(track, pfn, pfn + 1); - for (int i = 0; chunk->phys[i]; i++) { + for (int i = 0; i < ARRAY_SIZE(chunk->phys) && chunk->phys[i]; i++) { pfn = PHYS_PFN(chunk->phys[i]); __kho_unpreserve(track, pfn, pfn + 1); } @@ -992,7 +992,7 @@ void *kho_restore_vmalloc(const struct kho_vmalloc *preservation) while (chunk) { struct page *page; - for (int i = 0; chunk->phys[i]; i++) { + for (int i = 0; i < ARRAY_SIZE(chunk->phys) && chunk->phys[i]; i++) { phys_addr_t phys = chunk->phys[i]; if (idx + contig_pages > total_pages) base-commit: dcb6fa37fd7bc9c3d2b066329b0d27dedf8becaa -- 2.47.3