| Message ID | 20230128063229.989058-1-mawupeng1@huawei.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Add overflow checks for several syscalls | expand |
On 28.01.23 07:32, Wupeng Ma wrote: > 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 Do you have some test cases and could we add them to LTP, for example?
On 2023/2/4 1:10, David Hildenbrand wrote: > On 28.01.23 07:32, Wupeng Ma wrote: >> 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 > > Do you have some test cases and could we add them to LTP, for example? The basic idea is setting param len to ULONG_MAX. while will overflow if PAGE_ALIGN(len). Here are some simple examples: mlock(addr, ULONG_MAX); set_mempolicy_home_node(addr, ULONG_MAX, 0, 0); mbind(addr, ULONG_MAX, MPOL_BIND, &nodemask, max_node, MPOL_MF_MOVE_ALL); msync(addr, ULONG_MAX, MS_ASYNC); >
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(-)