On Sat, Mar 09, 2019 at 12:07:34AM +0800, Xin Long wrote:
> As does in __sctp_connect(), when checking addrs in a while loop, after
> get the addr len according to sa_family, it's necessary to do the check
> walk_size + af->sockaddr_len > addrs_size to make sure it won't access
> an out-of-bounds addr.
>
> The same thing is needed in selinux_sctp_bind_connect(), otherwise an
> out-of-bounds issue can be triggered:
>
> [14548.772313] BUG: KASAN: slab-out-of-bounds in
> selinux_sctp_bind_connect+0x1aa/0x1f0
> [14548.927083] Call Trace:
> [14548.938072] dump_stack+0x9a/0xe9
> [14548.953015] print_address_description+0x65/0x22e
> [14548.996524] kasan_report.cold.6+0x92/0x1a6
> [14549.015335] selinux_sctp_bind_connect+0x1aa/0x1f0
> [14549.036947] security_sctp_bind_connect+0x58/0x90
> [14549.058142] __sctp_setsockopt_connectx+0x5a/0x150 [sctp]
> [14549.081650] sctp_setsockopt.part.24+0x1322/0x3ce0 [sctp]
>
> Fixes: d452930fd3b9 ("selinux: Add SCTP support")
> Reported-by: Chunyu Hu <ch...@redhat.com>
> Signed-off-by: Xin Long <lucien....@gmail.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leit...@gmail.com>
Paul, how can we get this into -stable trees? SELinux process may be
different from -net trees.
> ---
> security/selinux/hooks.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index f0e36c3..dac9bdb 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -5120,6 +5120,9 @@ static int selinux_sctp_bind_connect(struct sock *sk,
> int optname,
> return -EINVAL;
> }
>
> + if (walk_size + len > addrlen)
> + return -EINVAL;
> +
> err = -EINVAL;
> switch (optname) {
> /* Bind checks */
> --
> 2.1.0
>
