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 v2[2]: - modified the way of checking overflows based on Andrew's comments 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/ [2]: https://lore.kernel.org/linux-mm/20230116115813.2956935-5-mawupeng1@xxxxxxxxxx/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 | 18 ++++++++++++------ mm/mlock.c | 14 ++++++++++++-- mm/msync.c | 9 ++++++--- 3 files changed, 30 insertions(+), 11 deletions(-) -- 2.25.1
