Author: andre Date: Fri Jul 5 14:30:54 2013 New Revision: 252787 URL: http://svnweb.freebsd.org/changeset/base/252787
Log: MFC r249317: Fix a race condition on tcp listen socket teardown with pending connections in the accept queue and contiguous new incoming SYNs. Compared to the original submitters patch I've moved the test next to the SYN handling to have it together in a logical unit and reworded the comment explaining the issue. Submitted by: Matt Miller <[email protected]> Submitted by: Juan Mojica <[email protected]> Reviewed by: Matt Miller (changes) Tested by: pho Modified: stable/9/sys/netinet/tcp_input.c Directory Properties: stable/9/sys/ (props changed) Modified: stable/9/sys/netinet/tcp_input.c ============================================================================== --- stable/9/sys/netinet/tcp_input.c Fri Jul 5 14:24:37 2013 (r252786) +++ stable/9/sys/netinet/tcp_input.c Fri Jul 5 14:30:54 2013 (r252787) @@ -1375,6 +1375,15 @@ relocked: */ INP_INFO_UNLOCK_ASSERT(&V_tcbinfo); return; + } else if (tp->t_state == TCPS_LISTEN) { + /* + * When a listen socket is torn down the SO_ACCEPTCONN + * flag is removed first while connections are drained + * from the accept queue in a unlock/lock cycle of the + * ACCEPT_LOCK, opening a race condition allowing a SYN + * attempt go through unhandled. + */ + goto dropunlock; } #ifdef TCP_SIGNATURE _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-stable-9 To unsubscribe, send any mail to "[email protected]"
