• Daniel Borkmann's avatar
    net: sctp: fix sctp_connectx abi for ia32 emulation/compat mode · ffd59393
    Daniel Borkmann authored
    SCTP's sctp_connectx() abi breaks for 64bit kernels compiled with 32bit
    emulation (e.g. ia32 emulation or x86_x32). Due to internal usage of
    'struct sctp_getaddrs_old' which includes a struct sockaddr pointer,
    sizeof(param) check will always fail in kernel as the structure in
    64bit kernel space is 4bytes larger than for user binaries compiled
    in 32bit mode. Thus, applications making use of sctp_connectx() won't
    be able to run under such circumstances.
    
    Introduce a compat interface in the kernel to deal with such
    situations by using a 'struct compat_sctp_getaddrs_old' structure
    where user data is copied into it, and then sucessively transformed
    into a 'struct sctp_getaddrs_old' structure with the help of
    compat_ptr(). That fixes sctp_connectx() abi without any changes
    needed in user space, and lets the SCTP test suite pass when compiled
    in 32bit and run on 64bit kernels.
    
    Fixes: f9c67811 ("sctp: Fix regression introduced by new sctp_connectx api")
    Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
    Acked-by: default avatarNeil Horman <nhorman@tuxdriver.com>
    Acked-by: default avatarVlad Yasevich <vyasevich@gmail.com>
    Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
    ffd59393
socket.c 200 KB