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
