Date: Fri, 28 Feb 2020 11:16:41 +0000 (UTC) From: "Bjoern A. Zeeb" <bz@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r358427 - head/sys/netinet6 Message-ID: <202002281116.01SBGf22003044@repo.freebsd.org>
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Author: bz Date: Fri Feb 28 11:16:41 2020 New Revision: 358427 URL: https://svnweb.freebsd.org/changeset/base/358427 Log: mld6: 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. MFC after: 3 days Sponsored by: Netflix Modified: head/sys/netinet6/mld6.c Modified: head/sys/netinet6/mld6.c ============================================================================== --- head/sys/netinet6/mld6.c Fri Feb 28 10:57:23 2020 (r358426) +++ head/sys/netinet6/mld6.c Fri Feb 28 11:16:41 2020 (r358427) @@ -3159,6 +3159,7 @@ 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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