um: Fix potential integer overflow during physmem setup

[ Upstream commit a98b7761f697e590ed5d610d87fa12be66f23419 ]

This issue happens when the real map size is greater than LONG_MAX,
which can be easily triggered on UML/i386.

Fixes: fe205bdd13 ("um: Print minimum physical memory requirement")
Signed-off-by: Tiwei Bie <tiwei.btw@antgroup.com>
Link: https://patch.msgid.link/20240916045950.508910-3-tiwei.btw@antgroup.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Tiwei Bie 2024-09-16 12:59:48 +08:00 committed by Greg Kroah-Hartman
parent 5398de330c
commit 5c710f4581

View file

@ -80,10 +80,10 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
unsigned long len, unsigned long long highmem)
{
unsigned long reserve = reserve_end - start;
long map_size = len - reserve;
unsigned long map_size = len - reserve;
int err;
if(map_size <= 0) {
if (len <= reserve) {
os_warn("Too few physical memory! Needed=%lu, given=%lu\n",
reserve, len);
exit(1);
@ -94,7 +94,7 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
err = os_map_memory((void *) reserve_end, physmem_fd, reserve,
map_size, 1, 1, 1);
if (err < 0) {
os_warn("setup_physmem - mapping %ld bytes of memory at 0x%p "
os_warn("setup_physmem - mapping %lu bytes of memory at 0x%p "
"failed - errno = %d\n", map_size,
(void *) reserve_end, err);
exit(1);