Comment 9 for bug 1804542

The originally flagged patch was [2/2] of a 2-patch set (AIUI), and the second doesn't make much sense to include without the first. The two patches also had a tiny dependence on a one tiny piece of an earlier third patch that was a smorgasbord of valgrind memcheck fixes. Applying these three commits (and omitting their modifications to CHANGES or other files) goes cleanly:

trent:~/ubuntu/Bind9/sru.1804542/bind9-gu$ patch -p1 < ../bind9/A-memset-the-remainder-of-sendcmsgbuf-to-0-in-a-attemp.patch
patching file lib/isc/unix/socket.c
Hunk #1 succeeded at 1529 (offset 4 lines).
Hunk #2 succeeded at 1550 (offset 4 lines).
Hunk #3 succeeded at 1636 (offset 4 lines).
trent:~/ubuntu/Bind9/sru.1804542/bind9-gu$ patch -p1 < ../bind9/B-Fix-socket-cmsg-buffer-usage.patch
patching file lib/isc/unix/socket.c
Hunk #1 succeeded at 373 (offset -2 lines).
Hunk #2 succeeded at 483 (offset -2 lines).
Hunk #3 succeeded at 1434 (offset -7 lines).
Hunk #4 succeeded at 1447 (offset -7 lines).
Hunk #5 succeeded at 1528 (offset -7 lines).
Hunk #6 succeeded at 1547 (offset -7 lines).
Hunk #7 succeeded at 1576 (offset -8 lines).
Hunk #8 succeeded at 1607 (offset -8 lines).
Hunk #9 succeeded at 1638 (offset -8 lines).
Hunk #10 succeeded at 1665 (offset -9 lines).
Hunk #11 succeeded at 1768 (offset -4 lines).
Hunk #12 succeeded at 1872 (offset -4 lines).
Hunk #13 succeeded at 2068 (offset -4 lines).
Hunk #14 succeeded at 2309 (offset -4 lines).
Hunk #15 succeeded at 2323 (offset -4 lines).
Hunk #16 succeeded at 2339 (offset -4 lines).
Hunk #17 succeeded at 2386 (offset -4 lines).
Hunk #18 succeeded at 2414 (offset -4 lines).
trent:~/ubuntu/Bind9/sru.1804542/bind9-gu$ patch -p1 < ../bind9/C-Use-completely-static-sized-buffers.patch
patching file lib/isc/unix/socket.c
Hunk #1 succeeded at 317 (offset -2 lines).
Hunk #2 succeeded at 402 (offset -2 lines).
Hunk #3 succeeded at 1474 (offset -7 lines).
Hunk #4 succeeded at 1552 (offset -7 lines).
Hunk #5 succeeded at 1571 (offset -7 lines).
Hunk #6 succeeded at 1602 (offset -8 lines).
Hunk #7 succeeded at 1633 (offset -8 lines).
Hunk #8 succeeded at 1658 with fuzz 1 (offset -8 lines).
Hunk #9 succeeded at 1791 (offset -4 lines).
Hunk #10 succeeded at 1894 (offset -4 lines).
Hunk #11 succeeded at 2090 (offset -4 lines).
Hunk #12 succeeded at 2310 (offset -4 lines).
Hunk #13 succeeded at 2330 (offset -4 lines).
Hunk #14 succeeded at 2775 (offset -4 lines).

The attached patch is what we should land for bionic to resolve this issue.