Date: Mon, 2 Mar 2020 13:23:29 +0000 (UTC) From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-12@freebsd.org Subject: svn commit: r358542 - stable/12/sys/netinet6 Message-ID: <202003021323.022DNT7j011365@repo.freebsd.org>
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Author: bz Date: Mon Mar 2 13:23:28 2020 New Revision: 358542 URL: https://svnweb.freebsd.org/changeset/base/358542 Log: MFC r358427: initialize oifp to avoid bogus results/panics in edge cases In certain cases (probably not during normal operation but observed in the lab during development) ip6_ouput() could return without error and ifpp (&oifp) not updated. Given oifp was never initialized we would take the later branch as oifp was not NULL, and when calling icmp6_ifstat_inc() we would panic dereferencing a garbage pointer. For code stability initialize oifp to NULL before first use to always have a deterministic value and not rely on a called function to behave and always and for ever do the work for us as we hope for. Sponsored by: Netflix Modified: stable/12/sys/netinet6/mld6.c Directory Properties: stable/12/ (props changed) Modified: stable/12/sys/netinet6/mld6.c ============================================================================== --- stable/12/sys/netinet6/mld6.c Mon Mar 2 13:16:40 2020 (r358541) +++ stable/12/sys/netinet6/mld6.c Mon Mar 2 13:23:28 2020 (r358542) @@ -3155,6 +3155,7 @@ mld_dispatch_packet(struct mbuf *m) mld = (struct mld_hdr *)(mtod(md, uint8_t *) + off); type = mld->mld_type; + oifp = NULL; error = ip6_output(m0, &mld_po, NULL, IPV6_UNSPECSRC, &im6o, &oifp, NULL); if (error) {
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