Re: [PATCH v4 0/4] Add overflow checks for several syscalls

[mawupeng]

Sorry for wasting your time.

I send the wrong version of this patchset, this is the older version.

I will send the right one later.

On 2023/3/20 10:47, Wupeng Ma wrote:
> 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.
> 
> Here is the testcases:
> 
>   #include <stdio.h>
>   #define _GNU_SOURCE
>   #include <sys/mman.h>
>   #include <fcntl.h>
>   #include <errno.h>
>   #include <unistd.h>
>   #include <string.h>
>   #include <limits.h>
>   #include <numaif.h>
>   
>   extern int errno;
>   int main(void)
>   {
>       int fd;
>       int ret;
>       void *addr;
>       int size = getpagesize();
>   
>       fd = open("/tmp/testfile", O_RDWR | O_CREAT);
>       if (fd < 0) {
>           printf("open file error! errno: %d\n", errno);
>           return -1;
>       }
>       printf("open success\n");
>       addr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
>       if (addr == MAP_FAILED) {
>           printf("open file error! errno: %d\n", errno);
>           close(fd);
>           return -1;
>       }
>       printf("mmap success\n");
>       memset(addr, 0, size);
>   
>       printf("==== mlock ====\n");
>       ret = mlock(addr, ULONG_MAX);
>       if (ret == -1 && errno == EINVAL)
>           printf("mlock test passed\n");
>       else
>           printf("mlock test failed, ret: %d, errno: %d\n", ret, errno);
>   
>       printf("==== set_mempolicy_home_node ====\n");
>       ret = syscall(450, addr, ULONG_MAX, 0, 0);
>       if (ret == -1 && errno == EINVAL)
>           printf("set_mempolicy_home_node test passed\n");
>       else
>           printf("set_mempolicy_home_node test failed, ret: %d, errno: %d\n", ret, errno);
>   
>       printf("==== mbind ====\n");
>       unsigned long nodemask = 1Ul << 0;
>       long max_node = 8 * sizeof(nodemask);
>       ret = mbind(addr, ULONG_MAX, MPOL_BIND, &nodemask, max_node, MPOL_MF_MOVE_ALL);
>       if (ret == -1 && errno == EINVAL)
>           printf("mbind test passed\n");
>       else
>           printf("mbind test failed, ret: %d, errno: %d\n", ret, errno);
>   
>       printf("==== msync ====\n");
>       ret = msync(addr, ULONG_MAX, MS_ASYNC);
>       if (ret == -1 && errno == ENOMEM)
>           printf("mbind test passed\n");
>       else
>           printf("mbind test failed, ret: %d, errno: %d\n", ret, errno);
>   
>       munmap(mmap, size);
>   
>       return 0;
>   }
> 
> Changelog since v3[3]:
> - rebase to the latest master
> - add simple testcases
> 
> 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/
> [3]: https://lore.kernel.org/linux-mm/de4149c7-0e6e-2035-3fb8-2f9da9633704@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 | 6 ++++--
>  mm/mlock.c     | 8 ++++++++
>  mm/msync.c     | 3 ++-
>  3 files changed, 14 insertions(+), 3 deletions(-)
>