[PATCH v2 0/4] Add overflow checks for several syscalls
From: Wupeng Ma
Date: Mon Jan 16 2023 - 06:59:24 EST
From: Ma Wupeng <mawupeng1@xxxxxxxxxx>
While testing mlock, we have a problem if the len of mlock is ULONG_MAX.
The return value of mlock is zero. But nothing will be locked since the
len in do_mlock overflows to zero due to the following code in mlock:
len = PAGE_ALIGN(len + (offset_in_page(start)));
The same problem happens in munlock.
Add new check and return -EINVAL to fix this overflowing scenarios since
they are absolutely wrong.
Similar logic is used to fix problems with multiple syscalls.
Changelog since v1[1]:
- only check overflow rather than access_ok to keep backward-compatibility
[1]: https://lore.kernel.org/lkml/20221228141701.c64add46c4b09aa17f605baf@xxxxxxxxxxxxxxxxxxxx/T/
Ma Wupeng (4):
mm/mlock: return EINVAL if len overflows for mlock/munlock
mm/mempolicy: return EINVAL for if len overflows for
set_mempolicy_home_node
mm/mempolicy: return EINVAL if len overflows for mbind
mm/msync: return ENOMEM if len overflows for msync
mm/mempolicy.c | 6 ++++--
mm/mlock.c | 8 ++++++++
mm/msync.c | 3 ++-
3 files changed, 14 insertions(+), 3 deletions(-)
--
2.25.1