The restored FDT contains the physical address of the LUO FLB header, which LUO maps before using the restored FLB metadata. Check that the FLB header range is KHO-preserved before calling phys_to_virt(). Reject invalid page counts and counts above LUO_FLB_MAX before walking the restored FLB array. Signed-off-by: Cris Jacob Maamor --- kernel/liveupdate/luo_flb.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/kernel/liveupdate/luo_flb.c b/kernel/liveupdate/luo_flb.c index 00f5494812c4..e80032669cea 100644 --- a/kernel/liveupdate/luo_flb.c +++ b/kernel/liveupdate/luo_flb.c @@ -162,6 +162,7 @@ static int luo_flb_retrieve_one(struct liveupdate_flb *flb) struct luo_flb_header *fh = &luo_flb_global.incoming; struct liveupdate_flb_op_args args = {0}; bool found = false; + u64 count; int err; guard(mutex)(&private->incoming.lock); @@ -175,7 +176,14 @@ static int luo_flb_retrieve_one(struct liveupdate_flb *flb) if (!fh->active) return -ENODATA; - for (int i = 0; i < fh->header_ser->count; i++) { + count = fh->header_ser->count; + if (count > LUO_FLB_MAX) { + pr_err("Invalid FLB count: %llu\n", + (unsigned long long)count); + return -EINVAL; + } + + for (u64 i = 0; i < count; i++) { if (!strcmp(fh->ser[i].name, flb->compatible)) { private->incoming.data = fh->ser[i].data; private->incoming.count = fh->ser[i].count; @@ -620,7 +628,20 @@ int __init luo_flb_setup_incoming(void *fdt_in) } header_ser_pa = get_unaligned((u64 *)ptr); + if (!kho_is_preserved(header_ser_pa, LUO_FLB_PGCNT)) { + pr_err("FLB header is not KHO preserved: %#llx\n", + (unsigned long long)header_ser_pa); + return -EINVAL; + } + header_ser = phys_to_virt(header_ser_pa); + if (header_ser->pgcnt != LUO_FLB_PGCNT || + header_ser->count > LUO_FLB_MAX) { + pr_err("Invalid FLB header: pgcnt %llu count %llu\n", + (unsigned long long)header_ser->pgcnt, + (unsigned long long)header_ser->count); + return -EINVAL; + } luo_flb_global.incoming.header_ser = header_ser; luo_flb_global.incoming.ser = (void *)(header_ser + 1); -- 2.53.0