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Subject[PATCH v3 0/4] Add overflow checks for several syscalls
Date
From: Ma Wupeng <mawupeng1@huawei.com>

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@linux-foundation.org/T/
[2]: https://lore.kernel.org/linux-mm/20230116115813.2956935-5-mawupeng1@huawei.com/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

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