Fix sctp privilege elevation (CVE-2006-3745)

sctp_make_abort_user() now takes the msg_len along with the msg
so that we don't have to recalculate the bytes in iovec.
It also uses memcpy_fromiovec() so that we don't go beyond the
length allocated.

It is good to have this fix even if verify_iovec() is fixed to
return error on overflow.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 1 deletions

diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 54722e622e6d..fde3f55bfd4b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1520,8 +1520,16 @@ SCTP_STATIC int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
                         goto out_unlock;
                 }
                 if (sinfo_flags & SCTP_ABORT) {
+                        struct sctp_chunk *chunk;
+
+                        chunk = sctp_make_abort_user(asoc, msg, msg_len);
+                        if (!chunk) {
+                                err = -ENOMEM;
+                                goto out_unlock;
+                        }
+
                         SCTP_DEBUG_PRINTK("Aborting association: %p\n", asoc);
-                        sctp_primitive_ABORT(asoc, msg);
+                        sctp_primitive_ABORT(asoc, chunk);
                         err = 0;
                         goto out_unlock;
                 }