From: Pratyush Yadav Date: Mon, 3 Nov 2025 11:01:57 +0000 (+0100) Subject: kho: fix out-of-bounds access of vmalloc chunk X-Git-Tag: v6.18-rc6~40^2~2 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0b07092d09e54e49b85379a9c60f82d54a881514;p=thirdparty%2Flinux.git kho: fix out-of-bounds access of vmalloc chunk 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. Link: https://lkml.kernel.org/r/20251103110159.8399-1-pratyush@kernel.org Fixes: a667300bd53f ("kho: add support for preserving vmalloc allocations") Signed-off-by: Pratyush Yadav Reviewed-by: Mike Rapoport (Microsoft) Cc: Alexander Graf Cc: Baoquan He Cc: Pasha Tatashin Signed-off-by: Andrew Morton --- diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c index 2a8c20c238a8..36fdce2667c5 100644 --- a/kernel/kexec_handover.c +++ b/kernel/kexec_handover.c @@ -889,7 +889,7 @@ 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); } @@ -1012,7 +1012,7 @@ 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)