Re: [PATCH v2] fs: select/pselect buffer overrun with x32 abi

[Lance Richardson <lance.richardson.net@gmail.com>]

On Tue, Feb 27, 2018 at 10:31:44AM -0500, Lance Richardson wrote:
> The definition of fd_set in X32 user-space uses a 32-bit base
> data type for the fd array while the kernel uses a 64-bit base
> data type. For applications using the glibc implementation of
> select(2)/pselect(2), the size of fd_set is an integer multiple
> of both base types, so there is no issue.
> 
> For applications using fd_set sizes that are different from
> the glibc default size, an overrun of the user-space fd_set
> buffer will occur when the user-space buffer size is an odd
> multiple of 4 bytes (e.g. user-space can pass a 12-byte fd_set
> to the kernel and the kernel will copy 16 bytes to user-space
> before returning from select/pselect system calls). OpenSSH is
> one example of an application using fd_set sizes different from
> the default.
> 

Please let me know if there is a more appropriate list for patches
in this area, or if there is a better list for x32 ABI issues.

Thanks,

   Lance Richardson