Date: Fri, 6 Apr 2018 17:20:37 +0000 (UTC) From: "Jonathan T. Looney" <jtl@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r332120 - head/sys/netinet Message-ID: <201804061720.w36HKb8A062208@repo.freebsd.org>
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Author: jtl Date: Fri Apr 6 17:20:37 2018 New Revision: 332120 URL: https://svnweb.freebsd.org/changeset/base/332120 Log: If a user closes the socket before we call tcp_usr_abort(), then tcp_drop() may unlock the INP. Currently, tcp_usr_abort() does not check for this case, which results in a panic while trying to unlock the already-unlocked INP (not to mention, a use-after-free violation). Make tcp_usr_abort() check the return value of tcp_drop(). In the case where tcp_drop() returns NULL, tcp_usr_abort() can skip further steps to abort the connection and simply unlock the INP_INFO lock prior to returning. Reviewed by: glebius MFC after: 2 weeks Sponsored by: Netflix, Inc. Modified: head/sys/netinet/tcp_usrreq.c Modified: head/sys/netinet/tcp_usrreq.c ============================================================================== --- head/sys/netinet/tcp_usrreq.c Fri Apr 6 17:17:34 2018 (r332119) +++ head/sys/netinet/tcp_usrreq.c Fri Apr 6 17:20:37 2018 (r332120) @@ -1095,7 +1095,9 @@ tcp_usr_abort(struct socket *so) !(inp->inp_flags & INP_DROPPED)) { tp = intotcpcb(inp); TCPDEBUG1(); - tcp_drop(tp, ECONNABORTED); + tp = tcp_drop(tp, ECONNABORTED); + if (tp == NULL) + goto dropped; TCPDEBUG2(PRU_ABORT); TCP_PROBE2(debug__user, tp, PRU_ABORT); } @@ -1106,6 +1108,7 @@ tcp_usr_abort(struct socket *so) inp->inp_flags |= INP_SOCKREF; } INP_WUNLOCK(inp); +dropped: INP_INFO_RUNLOCK(&V_tcbinfo); }
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